The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.



Image:Mars pathfinder panorama large.jpg|View from Mars Pathfinder.

Image:Pathfinder01.jpg|The Sojourner Rover is taking its Alpha Proton X-ray Spectrometer measurement of the Yogi Rock

Yogi Rock

Yogi Rock is a rock on Mars that was discovered during the Mars Pathfinder mission in 1997, and named by Geoffrey A. Landis. The rocks found on the mission were named after famous icons and figures, and Yogi Rock was thought to resemble the head of a bear looking away from the spacecraft...

 (NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

). Note: Sojourner Rover was the rover part of the Mars Pathfinder. It rolled off of the lander. This picture was taken by the lander.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.



Image:Mars pathfinder panorama large.jpg|View from Mars Pathfinder.

Image:Pathfinder01.jpg|The Sojourner Rover is taking its Alpha Proton X-ray Spectrometer measurement of the Yogi Rock

Yogi Rock

Yogi Rock is a rock on Mars that was discovered during the Mars Pathfinder mission in 1997, and named by Geoffrey A. Landis. The rocks found on the mission were named after famous icons and figures, and Yogi Rock was thought to resemble the head of a bear looking away from the spacecraft...

 (NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

). Note: Sojourner Rover was the rover part of the Mars Pathfinder. It rolled off of the lander. This picture was taken by the lander.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.



Image:Mars pathfinder panorama large.jpg|View from Mars Pathfinder.

Image:Pathfinder01.jpg|The Sojourner Rover is taking its Alpha Proton X-ray Spectrometer measurement of the Yogi Rock

Yogi Rock

Yogi Rock is a rock on Mars that was discovered during the Mars Pathfinder mission in 1997, and named by Geoffrey A. Landis. The rocks found on the mission were named after famous icons and figures, and Yogi Rock was thought to resemble the head of a bear looking away from the spacecraft...

 (NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

). Note: Sojourner Rover was the rover part of the Mars Pathfinder. It rolled off of the lander. This picture was taken by the lander.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.
The Oxia Palus quadrangle

Quadrangle (geography)

In geology or geography, the word "quadrangle" usually refers to a United States Geological Survey 7.5-minute quadrangle map, which are usually named after a local physiographic feature. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas...

is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey

United States Geological Survey

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) Astrogeology Research Program

Astrogeology Research Program

The USGS Astrogeology Science Center has a rich history of participation in space exploration efforts and planetary mapping, starting in 1963 when the Flagstaff Science Center was established by Gene Shoemaker to provide lunar geologic mapping and assist in training astronauts destined for the...

. The Oxia Palus quadrangle is also referred to as MC-11 (Mars Chart-11).

The quadrangle covers the region of 0° to 45° west longitude and 0° to 30° north latitude on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Mars Pathfinder

Mars Pathfinder

Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 landed in the Oxia Palus quadrangle at 19.13° N and 33.22° W, on July 4, 1997. Crater names in Oxia Palus are a Who's Who for famous scientists. Besides Galilaei

Galilaei

Galilaei is the name of two craters named after the astronomer Galileo Galilei:*Galilaei , on the Moon*Galilaei , on Mars...

 and DaVinci, some of the people who discovered the atom and radiation are honored there: Curie

Marie Curie

Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

, Becquerel

Henri Becquerel

Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...

, and Rutherford

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

. Mawrth Vallis

Mawrth Vallis

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometres below datum. It is an ancient water outflow channel with light-colored clay-rich rocks.Mawrth Vallis is one of the oldest valleys on Mars...

 was strongly considered as a landing site for NASA's next Mars rover, the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. A variety of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals have been found in Oxia Palus. Clay is formed in water, and it is good for preserving microscopic evidence of ancient life. Recently, scientists have found strong evidence for a lake located in the Oxia Palus quadrangle that received drainage from Shalbatana Vallis. The study, carried out with HiRISE images, indicates that water formed a 30-mile-long canyon that opened up into a valley, deposited sediment, and created a delta. This delta and others around the basin imply the existence of a large, long-lived lake. Of special interest is evidence that the lake formed after the warm, wet period was thought to have ended. So, lakes may have been around much longer than previously thought.

Surface appearance

The Mars Pathfinder found its landing site to contain a great deal of rocks. Analysis shows the area to have a greater density of rocks than 90% of Mars. Some of the rocks leaned against each other in a manner geologists term imbricated. It is believed strong flood waters in the past pushed the rocks around to face away from the flow. Some pebbles were rounded, perhaps from being tumbled in a stream. Some rocks have holes on their surfaces that seem to have been fluted by wind action. Small sand dunes are present. Parts of the ground are crusty, maybe due to cementing by a fluid containing minerals. In general the rocks show a dark gray color with patches of red dust or weathered appearance on their surfaces. Dust covers the lower 5–7 cm of some rocks, so they may have once been buried, but have now become exhumed. Three knobs, one large crater, and two small craters were visible on the horizon.

Types of Rocks

Results of Mars Pathfinder's Alpha Proton X-ray Spectrometer

APXS

An Alpha Particle X-Ray Spectrometer is a device that analyses the chemical element composition of a sample from the scattered alpha particles, emitted protons , and fluorescent X-rays after the sample is irradiated with alpha particles and X-rays from radioactive sources...

indicated that some rocks in the Oxia Palus quadrangle are like Earth's andesite

Andesite

Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

s. The discovery of andesites shows that some Martian rocks have been remelted and reprocessed. On Earth, Andesite forms when magma sits in pockets of rock while some of the iron and magnesium settle out. Consequently, the final rock contains less iron and magnesium and more silica. Volcanic rocks are usually classified by comparing the relative amount of alkalis (Na₂O and K₂O) with the amount of silica (SiO₂). Andesite is different than the rocks found in meteorites that have come from Mars.

By the time that final results of the mission were described in a series of articles in the Journal Science (December 5, 1997), it was believed that the rock Yogi contained a coating of dust, but was similar to the rock Barnacle Bill. Calculations suggest that the two rocks contain mostly the minerals orthopyroxene (magnesium-iron silicate), feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s (aluminum silicates of potassium, sodium, and calcium), quartz (silicon dioxide), with smaller amounts of magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, ilmenite

Ilmenite

Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

, iron sulfide, and calcium phosphate.



Image:Mars pathfinder panorama large.jpg|View from Mars Pathfinder.

Image:Pathfinder01.jpg|The Sojourner Rover is taking its Alpha Proton X-ray Spectrometer measurement of the Yogi Rock

Yogi Rock

Yogi Rock is a rock on Mars that was discovered during the Mars Pathfinder mission in 1997, and named by Geoffrey A. Landis. The rocks found on the mission were named after famous icons and figures, and Yogi Rock was thought to resemble the head of a bear looking away from the spacecraft...

 (NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

). Note: Sojourner Rover was the rover part of the Mars Pathfinder. It rolled off of the lander. This picture was taken by the lander.

Other Results from Pathfinder

By taking multiple images of the sky at different distances form the sun, scientists were able to determine that size of the particles in the pink haze was about 1 micrometer in radius. The color of some soils was similar to that of an iron oxyhydroxide phase which would support a warmer and wetter climate in the past.
Pathfinder carried a series of magnets to examine the magnetic component of the dust. Eventually, all but one of the magnets developed a coating of dust. Since the weakest magnet did not attract any soil, it was concluded that the airborne dust did not contain pure magnetite or one type of maghemite. The dust probably was an aggregate possible cemented with ferric oxide (Fe₂O₃).

Winds were usually less than 10 m/s. Dust devils were detected in the early afternoon.
The sky had a pink color. There was evidence of clouds and maybe fog.

River valleys and chaos

Many large, ancient river valleys are found in this area; along with collapsed features, called Chaos. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice. Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. More information and more examples of chaos can be found at Chaos terrain

Chaos terrain

Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...

. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.

One generally accepted view for the formation of large outflow channels is that they were formed by catastrophic floods of water released from giant groundwater reservoirs. Perhaps, the water started to come out of the ground due to faulting or volcanic activity. Sometimes hot magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 just travels under the surface. If that is the case, the ground will be heated, but there may be no evidence of lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 at the surface. After water escapes, the surface collapses. Moving across the surface, the water would have simultaneously froze and evaporated. Chunks of ice that would have rapidly formed may have enhanced the erosive power of the flood. Furthermore, the water may have frozen over at the surface, but continuing to flow underneath, eroding the ground as it moved along. Rivers in cold climates on the Earth often become ice-covered, yet continue to flow.

Such catastrophic floods have occurred on Earth. One commonly cited example is the Channeled Scabland of Washington State; it was formed by the breakout of water from the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 Lake Missoula. This region resembles the Martian outflow channels.

Lakes

Research, published in January 2010, suggests that Mars had lakes, each around 20 km wide, along parts of the equator, in the Oxia Palus quadrangle. Although earlier research showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much earlier period. Using detailed images from NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

, the researchers speculate that there may have been increased volcanic activity, meteorite impacts, or shifts in Mars' orbit during this period to warm Mars' atmosphere enough to melt the abundant ice present in the ground. Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist. In this new study, channels were discovered that connected lake basins near Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. When one lake filled up, its waters overflowed the banks and carved the channels to a lower area where another lake formed. These lakes would be another place to look for evidence of present or past life.

Aram Chaos

Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

 is an ancient impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 near the Martian equator, close to Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

. About 280 kilometres (174 mi) across, Aram lies in a region called Margaritifer Terra

Margaritifer Terra

Margaritifer Terra is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that are indicative of massive flooding. Wind erosion patterns are...

, where many water-carved channels show that floods poured out of the highlands onto the northern lowlands ages ago. The Thermal Emission Imaging System

Thermal Emission Imaging System

The Thermal Emission Imaging System is a camera on board the 2001 Mars Odyssey orbiter. It images Mars in the visible and infrared parts of the electromagnetic spectrum in order to determine the thermal properties of the surface and to refine the distribution of minerals on the surface of Mars as...

 (THEMIS) on the Mars Odyssey orbiter found gray crystalline hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 on the floor of Aram. Hematite

Hematite

Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 is an iron-oxide mineral that can precipitate when ground water circulates through iron-rich rocks, whether at normal temperatures or in hot springs. The floor of Aram contains huge blocks of collapsed, or chaotic, terrain that formed when water or ice was catastrophically removed. Elsewhere on Mars, the release of groundwater produced massive floods that eroded the large channels seen in Ares Vallis and similar outflow valleys. In Aram Chaos, however, the released water stayed mostly within the crater's ramparts, eroding only a small, shallow outlet channel in the eastern wall. Several minerals including hematite, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 minerals, and water-altered silicates in Aram suggests that a lake probably once existed within the crater. Because forming hematite requires liquid water, which could not long exist without a thick atmosphere, Mars must have had a much thicker atmosphere at some time in the past, when the hematite was formed.



Image:Erosion in Aram Chaos.JPG|Erosion in Aram Chaos

Aram Chaos

Aram Chaos, centered at 2.6°N, 21.5°W, comprises a heavily eroded impact crater on the planet Mars. It lies at the eastern end of the large canyon Valles Marineris and close to Ares Vallis. Various geological processes have reduced it to a circular area of chaotic terrain...

, as seen by THEMIS

Themis

Themis is an ancient Greek Titaness. She is described as "of good counsel", and is the embodiment of divine order, law, and custom. Themis means "divine law" rather than human ordinance, literally "that which is put in place", from the verb τίθημι, títhēmi, "to put"...

.


Image:Blocks in Aram.JPG|Blocks in Aram showing possible source of water, as seen by THEMIS

Themis

Themis is an ancient Greek Titaness. She is described as "of good counsel", and is the embodiment of divine order, law, and custom. Themis means "divine law" rather than human ordinance, literally "that which is put in place", from the verb τίθημι, títhēmi, "to put"...

.

Layered sediments

Oxia Palus is an interesting area with many craters showing layered sediments. Such sediments may have been deposited by water, wind, or volcanoes. The thickness of the layers is different in different craters. In Becquerel

Becquerel

The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...

 many layers are about 4 meters thick. In Crommelin crater the layers average 20 meters in thickness. At times, the top layer may be resistant to erosion and will form a feature called a Mensa

Mensa International

Mensa is the largest and oldest high-IQ society in the world. It is a non-profit organization open to people who score at the 98th percentile or higher on a standardised, supervised IQ or other approved intelligence test...

, the Latin word for table.

The pattern of layers within layers measured in Becquerel crater, suggests that each layer was formed over a period of about 100,000 years. Moreover, every 10 layers can be grouped into larger bundles. So every 10-layer pattern took one-million years to form (100,000 yrs./layer X 10 layers). The 10-layer pattern is repeated at least 10 times that is there are least 10 bundles, each consisting of 10 layers. It is believed that the layers relate to the cycle of changing tilt of Mars.

The tilt of the Earth's axis changes by only a little more than 2 degrees. In contrast Mars's tilt varies by tens of degrees. Today, the tilt (or obliquity) of Mars is low, so the poles are the coldest places on the planet, while the equator is the warmest. This causes gases in the atmosphere, like water and carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

, to migrate poleward, where they turn into ice. When the obliquity is higher, the poles receive more sunlight, and those materials migrate away. When carbon dioxide moves from the poles, the atmospheric pressure increases, maybe causing a difference in the ability of winds to transport and deposit sand. With more water in the atmosphere, sand grains deposited on the surface may stick and cement together to form layers.

This study was done using stereo topographic maps obtained by processing data from the high-resolution camera onboard NASA's Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

.



Image:Becquerel Crater layers.JPG|Becquerel

Becquerel (Martian crater)

Becquerel is a 167 km-diameter crater at 22.1°N, 352.0°E on Mars, in Arabia Terra. It is named after Antoine H. Becquerel.Photographs by the Mars Global Surveyor revealed layered sedimentary rocks in the crater. The layers appear to be only a few meters thick and show little variations in...

 layers, as seen by HiRISE

HiRISE

High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....

. Click on image to see fault.

Image:Marscratermounds.jpg|Mounds in craters showing layers are formed by the erosion of layers that were deposited after the impact.

Image:Crommlin Crater.JPG|Crommlin Crater

Crommlin Crater

Crommlin Crater is an impact crater in the Oxia Palus quadrangle of Mars. It is located at5.1° north and 10.2° west. It was named after Andrew C. Crommlin, a British astronomer ....

 Layered Deposit, as seen by HiRISE. The color blue in the photo is a false color.

Image:Punsk Crater.JPG|Punsk Crater

Punsk Crater

Púnsk Crater is an impact crater in the Oxia Palus quadrangle of Mars, located at 20.8° N and 41.2° W. It is 11.6 km in diameter and was named after Puńsk, Poland....

, as seen by HiRISE. Scale bar is 500 meters long. Click on image to see possible fine layers on floor. Image on right is an enlargement of south (bottom) wall of crater.

Image:Hydraotes Chaos.JPG|Hydraotes Chaos

Hydraotes Chaos

Hydraotes Chaos is a broken up region in the Oxia Palus quadrangle of Mars, located at 0.8° North and 35.4° West. It is 417.5 km across and was named after a classical albedo feature name. More information and more examples of Chaos can be found at Chaos terrain....

, as seen by HiRISE. Click on image to seen channels and layers. Scale bar is 1000 meters long.

Image:Grindavik Crater.JPG|Grindavik Crater

Grindavik Crater

Grindavik Crater is a crater in the Oxia Palus quadrangle of Mars, located at 25.39° North and 39.07° West. It is 12 km in diameter and was named after a town in Iceland....

, as seen by HiRISE. Scale bar is 1000 meters long.

Image:Layers in Monument Valley.jpg|Layers in Monument Valley. These are accepted as being formed, at least in part, by water deposition. Since Mars contains similar layers, water remains as a major cause of layering on Mars.

Wrinkle ridges

Many areas of Mars show wrinkles on the surface, called wrinkle ridges. They are elongated and are often found on smooth area of Mars. Because they are wide, gentle topographic highs, they are sometimes hard to see. Although first thought to be caused by lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 flows, they are now generally thought to be more likely caused by compressional tectonic forces that cause folding

Folding

Fold or folding may refer to:* Paper folding, the art of folding paper* Book folding, in book production* Skin fold, an area of skin that folds* Fold , in the game of poker, to discard one's hand and forfeit interest in the current pot...

 and faulting. A wrinkle ridge is visible in the image to the right of Ares Vallis.

Faults

A picture below right, taken of layers in Becquerel Crater, shows a straight line that represents a fault. Faults are breaks in rocks where movement has taken place. The movement may be only inches or much more. Faults can be very significant, as the break in the rock is a focus for erosion and, more importantly, can allow fluids containing dissolved minerals to rise, then be deposited. Some of the major ore deposits on Earth are formed by this process.

Springs

A study of images taken with the High Resolution Imaging Science Experiment (HiRISE

HiRISE

High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....

) on the Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter

Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

 strongly suggests that hot springs

Hot Springs

Hot Springs may refer to:* Hot Springs, Arkansas** Hot Springs National Park, Arkansas*Hot Springs, California**Hot Springs, Lassen County, California**Hot Springs, Modoc County, California**Hot Springs, Placer County, California...

 once existed in Vernal Crater

Vernal Crater

Vernal Crater is a crater on Mars, located at 6° north latitude and 355.5° west longitude in the Oxia Palus quadrangle. It is 57 km in diameter and was named after Vernal, Utah, USA...

, in the Oxia Palus quadrangle. These springs may have provided a long-time location for life. Furthermore, mineral deposits associated with these springs may have preserved traces of Martian life. In Vernal Crater on a dark part of the floor, two light-toned, elliptical structures closely resemble hot springs on the Earth. They have inner and outer halos, with roughly circular depressions. A large number of hills are lined up close to the springs. These are thought to have formed by the movement of fluids along the boundaries of dipping beds. A picture below shows these springs. One of the depressions is visible. The discovery of opaline silica by the Mars Rovers, on the surface also suggests the presence of hot springs. Opaline silica is often deposited in hot springs. Scientists proposed this area should be visited by the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

.



Image:Springs in Vernal Crater.jpg|Springs in Vernal Crater

Vernal Crater

Vernal Crater is a crater on Mars, located at 6° north latitude and 355.5° west longitude in the Oxia Palus quadrangle. It is 57 km in diameter and was named after Vernal, Utah, USA...

, as seen by HIRISE

HiRISE

High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....

Mojave Crater

Mojave Crater, in the Xanthe Terra

Xanthe Terra

Xanthe Terra is a large area on Mars, centered just north of the Martian equator. Its coordinates are and it covers 2465 km at its broadest extent. Its name means "golden-yellow land." It is in the Lunae Palus quadrangle and the Oxia Palus quadrangle....

 region, has alluvial fans that look remarkably similar to landforms in the Mojave Desert in the American southwest. Fans inside and around the outside of Mojave crater on Mars are a perfect match to Earth's alluvial fans. As on Earth, the largest rocks are near the mouths of the fans. Because channels start at the top of ridges, it is believed they were formed by heavy downpours. Researchers have suggested that rain may have initiated by impacts.

Mojave Crater is approximately 2,604 meters (1.63 miles) deep. Based on its diameter and depth, researchers believe it is very young. It has not been around long enough to accumulate material and start to fill. It is giving scientists great insight into impact processes on Mars since it is so fresh.



Image:Alluvial Fans in Mojave Crater.jpg|Alluvial Fans in Mojave Crater, as seen by HiRISE. High ground is on the right. Branched network of channels runs from higher ground (crater rim) to lower ground.

Image:Mojave Crater.jpg|Another view of Mojave Crater, as seen by HiRISE. North is at the bottom to aid in understanding image.

Other craters

Impact craters generally have rims with ejecta around them; in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10 km in diameter) they usually have a central peak. The peak is caused by a rebound of the crater floor following the impact. Sometimes craters display layers. Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed onto the surface. Hence, craters can show what lies deep under the surface.



Image:Trouvelot crater floor.JPG|Trouvelot Crater

Trouvelot Crater

Trouvelot Crater is a crater on Mars, located in the Oxia Palus quadrangle at 16.2° north latitude and 13.1° west longitude. It 154.7 km in diameter and was named after Étienne Léopold Trouvelot, a French astronomer ....

 floor, as seen by HiRISE

HiRISE

High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....

Image:Radau Crater.jpg|Central peak of Radau Crater

Radau Crater

Radau Crater is an impact crater in the Oxia Palus quadrangle of Mars,located 17.1° N and 4.8° W. It is 114.5 km in diameter and was named for Rodolphe Radau, a French astronomer ....

, as seen by HiRISE

Image:Kipini Crater.JPG|Kipini Crater

Kipini Crater

Kipini Crater is an impact crater in the Oxia Palus quadrangle of Mars. It is located at26.1° N and 31.6° W It is named after a Town in Kenya....

 south rim, as seen by HiRISE. Scale bar is 500 meters long.

Image:Sagan Crater.JPG|Sagan Crater

Sagan Crater

Sagan Crater is an impact crater in the Oxia Palus quadrangle of Mars. It is located at10.8° N and 30.7° W. It is named after Carl E. Sagan, an American astronomer . Dr. Sagan was a founder of the Planetary Society....

 Central Peak Ring, as seen by HiRISE. Scale bar is 500 meters long.

Image:Curie Crater.jpg|Curie Crater

Curie Crater

Curie Crater is an impact crater in the Oxia Palus quadrangle of Mars, located at 29.1° N and 4.8° W. It is 114.1 km in diameter and was named after Pierre Curie, a French physicist-chemist ....

, as seen by HiRISE

Image:Curie Crater Close-up .JPG|Close-up of layers in central mound of Curie Crater, as seen by HiRISE

Image:Taytay Crater.jpg|Tayray Crater

Tayray Crater

Taytay Crater is an impact crater in the Oxia Palus quadrangle of Mars, located at .37° N and 19.65° W. It is 18.4km in diameter and was named after Taytay Philippines....

, as seen by HiRISE

Image:23659largecells.jpg|Light toned rocks surrounded by dark material along wall of a crater, as seen by HiRISE under HiWish program

HiWish program

HiWish is a program created by NASA the so that anyone can suggest a place for the HiRISE camera on the Mars Reconnaissance Orbiter to photograph. It was started in January 2010. The first images were released in April 2010...

. Click on image for a better view.

Image:Pedestal Crater and ridge.JPG|Pedestal Crater and ridge in Oxia Palus quadrangle

Oxia Palus quadrangle

The Oxia Palus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The Oxia Palus quadrangle is also referred to as MC-11 ....

, as seen by HiRISE

HiRISE

High Resolution Imaging Science Experiment is a camera on board the Mars Reconnaissance Orbiter. The 65 kg , $40 million instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp....

. Click on image to see detail of the edge of the pedestal crater. The flat-topped ridge near the top of the image was once a river that became inverted. The pedestal crater superposes the ridge, so it is younger.

Image:Pedestal crater3.jpg|Pedestal craters form when the ejecta from impacts protect the underlying material from erosion. As a result of this process, craters appear perched above their surroundings.

Valli

Valli

Valli is a Goddess and the divine consort of the prominent Hindu God Murugan, according to Hindu mythology. She represents the "Ichha Shakti" , and Goddess Deivayanai depicts "Kriya Shakthi" , and the Vel embodies "Gnana Shakthi" .Valli in Tamil language means a creeper and is also used as a title...

s

Vallis (plural valles) is the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 word for valley

Valley

In geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...

. It is used in planetary geology

Planetary geology

Planetary geology, alternatively known as astrogeology or exogeology, is a planetary science discipline concerned with the geology of the celestial bodies such as the planets and their moons, asteroids, comets, and meteorites...

 for the naming of landform

Landform

A landform or physical feature in the earth sciences and geology sub-fields, comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography...

 features on other planets.

Vallis was used for old river valleys that were discovered on Mars, when probes were first sent to Mars. The Viking Orbiters caused a revolution in our ideas about water on Mars; huge river valleys were found in many areas. Spacecraft cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.



Image:Shalbatana Vallis.JPG|Shalbatana Vallis

Shalbatana Vallis

Shalbatana Vallis is an ancient water-worn channel on Mars, located in the Oxia Palus quadrangle at 7.8° north latitude and 42.1° west longitude. It is the westernmost of the southern Chryse outflow channels...

, as seen by HiRISE. The scale bar is 500 meters long.

Image:Shalbatana Vallis Floor.JPG|Shalbatana Vallis

Shalbatana Vallis

Shalbatana Vallis is an ancient water-worn channel on Mars, located in the Oxia Palus quadrangle at 7.8° north latitude and 42.1° west longitude. It is the westernmost of the southern Chryse outflow channels...

 Floor, as seen by HiRISE. Scale bar is 1000 meters long.

Image:Simud Valles close-up.JPG|Close-up of Simud Valles

Simud Valles

Simud Valles is an ancient outflow channel in the Oxia Palus quadrangle of Mars, located at 19.8° N and 37.8° W. It is 945.0 km long and was named for the word for "Mars" in Sumerian. Note: Descriptor term changed to the plural , and coordinates redefined 3/31/2008....

, as seen by HiRISE.

Image:Ares Vallis from Viking.jpg|Ares Vallis

Ares Vallis

Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water...

, as seen by Viking. The channel is 25 km wide and about 1 km deep.

Image:Channels in Ares Vallis Region.jpg|Channels in Ares Vallis Region, as seen by HiRISE.

Image:Ares Valles.JPG|Ares Valles, as seen by HiRISE

Image:Tiu Valles Ridges.JPG|Tiu Valles

Tiu Valles

Tiu Valles is an outflow channel in the Oxia Palus quadrangle of Mars, located at 15.9° North and 35.7° West.It is 1,720 km long and was named after the word for "Mars" in old English ....

 Ridges, as seen by HiRISE. Ridges were probably formed by running water. Scale bar is 1 km long.

Image:Viking Teardrop Islands.jpg|Teardrop-shaped islands caused by flood waters from Maja Valles

Maja Valles

Maja Valles is a large, ancient outflow channel in the Lunae Palus quadrangle on Mars. Its location is 12.6° north latitude and 58.3° west longitude. The name is a Nepali word for "Mars". Maja Valles begins at Juventae Chasma. Parts of the system have been partially buried by thin volcanic debris...

, as seen by Viking Orbiter. Image is located in Oxia Palus quadrangle. The islands are formed in the ejecta of Lod Crater, Bok Crater, and Gold Crater.

Other close-ups in Oxia Palus quadrangle

Image:Oxia Palus erosion.JPG|Erosion

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 has created huge pits with steep walls. Picture from Mars Odyssey THEMIS

Themis

Themis is an ancient Greek Titaness. She is described as "of good counsel", and is the embodiment of divine order, law, and custom. Themis means "divine law" rather than human ordinance, literally "that which is put in place", from the verb τίθημι, títhēmi, "to put"...

.

Image:Eos Chasma.JPG|Eos Chasma

Eos Chasma

Eos Chasma is a chasma in the southern part of the Valles Marineris canyon system of Mars.Eos Chasma’s western floor is mainly composed of an etched massive material composed of either volcanic or eolian deposits later eroded by the Martian wind. The eastern end of the Eos chasma has a large area...

 with a Mensa, a flat topped prominence with cliff-like edges, as seen by THEMIS. In many places rock layers are visible.

Image:Hydaspis Chaos.JPG|Hydaspis Chaos

Hydaspis Chaos

Hydaspis Chaos is a region in the Oxia Palus quadrangle of Mars, located at3.2° north latitude and 27.1° west longitude. The region is about 355 km across. It was named after a classical albedo feature.- River Valleys and Chaos :...

, as seen by HiRISE.

Image:Arabia Layers from HiRISE.jpg|Cyclic Bedding in Arabia Terra, as seen by HiRISE.

Image:Cliffs and canyons in Arabia.jpg|Cliffs and canyons in Arabia, as seen by HiRISE.

See also

• Climate of Mars
  Climate of Mars
  The climate of Mars has been an issue of scientific curiosity for centuries, not least because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth....
  
  
• Water on Mars
  Water on Mars
  Water on Mars is a psychedelic rock and electronic music group from Quebec City, Québec, Canada. The music trio is led by Philippe Navarro, guitarist, vocalist, arranger, producer, principal lyricist, and music composer....
  
  
• Geology of Mars
  Geology of Mars
  The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is fully analogous to the field of terrestrial geology. In planetary science, the term geology is...
  
  
• Impact crater
  Impact crater
  In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
  
  
• Vallis
  Vallis
  Vallis is the Latin word for valley. It is used in planetary geology for the naming of landform features on other planets....
  
  
• Chaos terrain
  Chaos terrain
  Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars and Jupiter's moon Europa...
  
  
• Pedestal crater
  Pedestal crater
  In planetary geology,a pedestal crater is a crater with its ejecta sitting above the surrounding terrain and thereby forming a raised platform. They form when an impact crater ejects material which forms an erosion-resistant layer, thus causing the immediate area to erode more slowly than the rest...
  
  

External links

• Accurate animations of flights over Mars in at 100 meter altitude

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