Protonilus Mensae
Encyclopedia
Protonilus Mensae is an area of Mars
in the Ismenius Lacus quadrangle
. It is centered on the coordinates of 43.86° N and 49.4° E. Its western and eastern longitudes are 37° E and 59.7° E. North and south latitudes are 47.06° N and 39.87° N. Protonilus Mensae is between Deuteronilus Mensae
and Nilosyrtis Mensae
; all lie along the Martian dichotomy
boundary. Its name was adapted by the IAU in 1973.
The surface is described as Fretted terrain
. This terrain contains cliffs, mesas, and wide flat valleys. Surface features are believed to have been caused by debris covered glaciers. These glaciers are termed Lobate debris apron
s (LDA) when surrounding mounds and mesas. When glaciers are in valleys, they are called Lineated valley fill
(LVF). Parts of the surface show flow patterns that start in numerous alcoves located within the walls of plateaus. Small flow lobes on top of main flows demonstrate that there was more than one glacial period, just as on Earth. It is strongly believed that beneath a thin layer of rock and dust lie vast reservoirs of ice. Radar data from the SHAllow RADar (SHARAD) on board MRO
have found pure ice under LDA and LVF. Some places in Protonilus Mensae display lines of pits. These pits may have formed when ground ice converted to a gas, thus leaving a void. When surface material collapses into voids, pits are created.
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...
in the Ismenius Lacus quadrangle
Ismenius Lacus quadrangle
The Ismenius Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The quadrangle is located in the northwestern portion of Mars’ eastern hemisphere and covers 0° to 60° east longitude and 30° to 65° north...
. It is centered on the coordinates of 43.86° N and 49.4° E. Its western and eastern longitudes are 37° E and 59.7° E. North and south latitudes are 47.06° N and 39.87° N. Protonilus Mensae is between Deuteronilus Mensae
Deuteronilus Mensae
Deuteronilus Mensae is a region on Mars 937 km across and centered at . It covers 344° -325° West and 40°-48° North. Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus quadrangle. It is along the dichotomy boundary, that is between the old,...
and Nilosyrtis Mensae
Nilosyrtis Mensae
Nilosyrtis Mensae is an area of Mars in the Casius quadrangle. It is centered on the coodinates of 36.87° N and 67.9° E. Its western and eastern longitudes are 51.1° E and 74.4° E. North and south latitudes are 36.87° N and 29.61° N. Nilosyrtis Mensae is just to the east of Protonilus Mensae...
; all lie along the Martian dichotomy
Martian dichotomy
The most conspicuous feature of Martian surface geology is a sharp contrast, known as the Martian dichotomy, between the rugged southern highlands and the relatively smooth northern basins. The two hemispheres differ in elevation by 1 to 3 km...
boundary. Its name was adapted by the IAU in 1973.
The surface is described as Fretted terrain
Fretted terrain
Fretted terrain is a type of surface feature common to certain areas of Mars and discovered in Mariner 9 images. It lies between two different types of terrain...
. This terrain contains cliffs, mesas, and wide flat valleys. Surface features are believed to have been caused by debris covered glaciers. These glaciers are termed Lobate debris apron
Lobate Debris Apron
Lobate debris aprons are geological features on Mars, first seen by the Viking Orbiters, consisting of piles of rock debris below cliffs. These features have a convex topography and a gentle slope from cliffs or escarpments, which suggest flow away from the steep source cliff...
s (LDA) when surrounding mounds and mesas. When glaciers are in valleys, they are called Lineated valley fill
Lineated valley fill
Lineated valley fill , also called lineated floor deposit, is a feature of the floors of some channels on Mars, exhibiting ridges and grooves that seem to flow around obstacles. Shadow measurements show that at least some of the ridges are several metres high. LVF is believed to be ice-rich. ...
(LVF). Parts of the surface show flow patterns that start in numerous alcoves located within the walls of plateaus. Small flow lobes on top of main flows demonstrate that there was more than one glacial period, just as on Earth. It is strongly believed that beneath a thin layer of rock and dust lie vast reservoirs of ice. Radar data from the SHAllow RADar (SHARAD) on board MRO
MRO
-Operations:* maintenance, repair, and operations -Companies:...
have found pure ice under LDA and LVF. Some places in Protonilus Mensae display lines of pits. These pits may have formed when ground ice converted to a gas, thus leaving a void. When surface material collapses into voids, pits are created.
See also
- 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...
- Deuteronilus MensaeDeuteronilus MensaeDeuteronilus Mensae is a region on Mars 937 km across and centered at . It covers 344° -325° West and 40°-48° North. Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus quadrangle. It is along the dichotomy boundary, that is between the old,...
- Martian dichotomyMartian dichotomyThe most conspicuous feature of Martian surface geology is a sharp contrast, known as the Martian dichotomy, between the rugged southern highlands and the relatively smooth northern basins. The two hemispheres differ in elevation by 1 to 3 km...
- Nilosyrtis MensaeNilosyrtis MensaeNilosyrtis Mensae is an area of Mars in the Casius quadrangle. It is centered on the coodinates of 36.87° N and 67.9° E. Its western and eastern longitudes are 51.1° E and 74.4° E. North and south latitudes are 36.87° N and 29.61° N. Nilosyrtis Mensae is just to the east of Protonilus Mensae...
- Ismenius Lacus quadrangleIsmenius Lacus quadrangleThe Ismenius Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The quadrangle is located in the northwestern portion of Mars’ eastern hemisphere and covers 0° to 60° east longitude and 30° to 65° north...
- GlacierGlacierA glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
- Glaciers on MarsGlaciers on MarsGlaciers formed much of the observable surface in large areas of Mars. Most of the area in high latitudes, especially the Ismenius Lacus quadrangle, is believed to still contain enormous amounts of water ice. Recent evidence has led many planetary scientists to believe that water ice still exists...