Arabia Terra
Encyclopedia
Arabia Terra is a large upland region in the north of Mars
in that lies mostly in the Arabia quadrangle
. It is densely cratered and heavily eroded. This battered topography indicates great age, and Arabia Terra is presumed to be one of the oldest terrains on the planet. It covers as much as 4500 kilometers at its longest extent, centered roughly at 19.79°N 30°E with its eastern and southern regions rising 4 kilometers above the north-west. Alongside its many craters, canyons wind through the Arabia Terra, many emptying into the large Northern lowlands of the planet, which borders Arabia Terra to the north.
Arabia contains many interesting features. There are some good examples of pedestal craters in the area. A pedestal crater has its ejecta above the surrounding terrain, often forming a steep cliff. The ejecta forms a resistant layer that protects the underlying material from erosion. Mounds and buttes on the floor of some craters display many layers. The layers may have formed by volcanic processes, by wind, or by underwater deposition. Dark slope streaks have been observed in Tikhonravov Basin, a large eroded crater. The streaks appear on steep slopes and change over time. At first they are dark, then turn a lighter color, probably by the deposition of fine, light colored dust from the atmosphere.These streaks are thought to form by dust moving downslope in a way similar to snow avalanches on Earth.
Arabia Terra was named in 1979 after a corresponding albedo feature
on a map by Giovanni Schiaparelli
, who named it in turn after the Arabian peninsula
.
Research on the region was undertaken in 1997 and the individuality of the province better defined. An equatorial belt was noted with a crater age distinctly younger than the northern part of the province and of Noachis Terra
to the south. This was interpreted as an "incipient back-arc system" provoked by the subduction
of Mars lowlands under Arabia Terra during Noachian times. Regional fracture patterns were also explained in this manner, and the rotational instability of the planet as a cause was not supported.
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 that lies mostly in the Arabia quadrangle
Arabia quadrangle
The Arabia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The Arabia quadrangle is also referred to as MC-12 ....
. It is densely cratered and heavily eroded. This battered topography indicates great age, and Arabia Terra is presumed to be one of the oldest terrains on the planet. It covers as much as 4500 kilometers at its longest extent, centered roughly at 19.79°N 30°E with its eastern and southern regions rising 4 kilometers above the north-west. Alongside its many craters, canyons wind through the Arabia Terra, many emptying into the large Northern lowlands of the planet, which borders Arabia Terra to the north.
Arabia contains many interesting features. There are some good examples of pedestal craters in the area. A pedestal crater has its ejecta above the surrounding terrain, often forming a steep cliff. The ejecta forms a resistant layer that protects the underlying material from erosion. Mounds and buttes on the floor of some craters display many layers. The layers may have formed by volcanic processes, by wind, or by underwater deposition. Dark slope streaks have been observed in Tikhonravov Basin, a large eroded crater. The streaks appear on steep slopes and change over time. At first they are dark, then turn a lighter color, probably by the deposition of fine, light colored dust from the atmosphere.These streaks are thought to form by dust moving downslope in a way similar to snow avalanches on Earth.
Arabia Terra was named in 1979 after a corresponding albedo feature
Albedo feature
An albedo feature is a large area on the surface of a planet which shows a contrast in brightness or darkness with adjacent areas....
on a map by Giovanni Schiaparelli
Giovanni Schiaparelli
Giovanni Virginio Schiaparelli was an Italian astronomer and science historian. He studied at the University of Turin and Berlin Observatory. In 1859-1860 he worked in Pulkovo Observatory and then worked for over forty years at Brera Observatory...
, who named it in turn after the Arabian peninsula
Arabian Peninsula
The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...
.
Research on the region was undertaken in 1997 and the individuality of the province better defined. An equatorial belt was noted with a crater age distinctly younger than the northern part of the province and of Noachis Terra
Noachis Terra
Noachis Terra is an extensive southern landmass of the planet Mars. It lies west of the giant Hellas impact basin, roughly between the latitudes −20° and −80° and longitudes 30° west and 30° east, centered on ....
to the south. This was interpreted as an "incipient back-arc system" provoked by the subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...
of Mars lowlands under Arabia Terra during Noachian times. Regional fracture patterns were also explained in this manner, and the rotational instability of the planet as a cause was not supported.