Amazonis quadrangle
Encyclopedia
The Amazonis quadrangle
is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey
(USGS) Astrogeology Research Program
. The Amazonis quadrangle is also referred to as MC-8 (Mars Chart-8).
The quadrangle covers the area from 135° to 180° west longitude and 0° to 30° north latitude on Mars
. This area is considered to be among the youngest parts of Mars because it has a very low density of craters. The Amazonia period is named after this area.
. It is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. The surface of the formation has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them and demonstrate the erosive power of Martian winds. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Another evidence for a fine-grained composition is that the area gives almost no radar return. For this reason it has been called a "stealth" region. Layers are seen in parts of the formation. Images from spacecraft show that they have different degrees of hardness probably because of significant variations in the physical properties, composition, particle size, and/or cementation. Very few impact craters are visible throughout the area so the surface is relatively young.
. It is called Lycus Sulci. Sulci is a Latin term that refers to the furrows on the surface of a brain, so Lycus Sulci has many furrows or grooves. The furrows are huge—up to a full kilometer deep. It would be extremely difficult to walk across it or to land a space ship there. A picture of this area is shown below.
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 protecting the immediate area from erosion. As a result of this hard covering, the crater and its ejecta become elevated, as erosion removes the softer material beyond the ejecta. Some pedestals have been accurately measured to be hundreds of meters above the surrounding area. This means that hundreds of meters of material were eroded away. Pedestal craters were first observed during the Mariner
missions.
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 Amazonis quadrangle is also referred to as MC-8 (Mars Chart-8).
The quadrangle covers the area from 135° to 180° 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...
. This area is considered to be among the youngest parts of Mars because it has a very low density of craters. The Amazonia period is named after this area.
Medusae Fossae Formation
The Amazonis quadrangle is of special interest to scientists because it contains a big part of a formation, called the Medusae Fossae FormationMedusae Fossae Formation
The Medusae Fossae Formation is a broad geological unit of uncertain origin on the planet Mars. It is named for the Medusa of Greek mythology. "Fossae" is Latin for "trenches"...
. It is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. The surface of the formation has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them and demonstrate the erosive power of Martian winds. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Another evidence for a fine-grained composition is that the area gives almost no radar return. For this reason it has been called a "stealth" region. Layers are seen in parts of the formation. Images from spacecraft show that they have different degrees of hardness probably because of significant variations in the physical properties, composition, particle size, and/or cementation. Very few impact craters are visible throughout the area so the surface is relatively young.
Sulci
A very rugged terrain extends from the base of Olympus MonsOlympus Mons
Olympus Mons is a large volcanic mountain on the planet Mars. At a height of almost , it is one of the tallest mountains in the Solar System, three times as tall as Mount Everest and more than twice the height of Mauna Kea the tallest mountain on Earth. Olympus Mons is the youngest of the large...
. It is called Lycus Sulci. Sulci is a Latin term that refers to the furrows on the surface of a brain, so Lycus Sulci has many furrows or grooves. The furrows are huge—up to a full kilometer deep. It would be extremely difficult to walk across it or to land a space ship there. A picture of this area is shown below.
Columnar Jointing
Lava flows sometimes cool to form large groups of more-or-less equally sized columns. The resolution of the HiRISE images is such that the columns were found in various locations in 2009.Craters
Impact craters generally have a rim 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 will 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 us what lies deep under the surface.A pedestal crater is a 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...
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 protecting the immediate area from erosion. As a result of this hard covering, the crater and its ejecta become elevated, as erosion removes the softer material beyond the ejecta. Some pedestals have been accurately measured to be hundreds of meters above the surrounding area. This means that hundreds of meters of material were eroded away. Pedestal craters were first observed during the Mariner
Mariner program
The Mariner program was a program conducted by the American space agency NASA that launched a series of robotic interplanetary probes designed to investigate Mars, Venus and Mercury from 1963 to 1973...
missions.
See also
- Amazonis PlanitiaAmazonis PlanitiaAmazonis Planitia is one of the smoothest plains on Mars. It is located between the Tharsis and Elysium volcanic provinces to the west of Olympus Mons in the Valles Marineris region of the Memnonia quadrangle, centered at...
- Water on MarsWater on MarsWater 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 MarsGeology of MarsThe 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 craterImpact craterIn 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...
- Pedestal craterPedestal craterIn 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...
- Medusae Fossae FormationMedusae Fossae FormationThe Medusae Fossae Formation is a broad geological unit of uncertain origin on the planet Mars. It is named for the Medusa of Greek mythology. "Fossae" is Latin for "trenches"...
- VallisVallisVallis is the Latin word for valley. It is used in planetary geology for the naming of landform features on other planets....