Arabia quadrangle
Map of Arabia quadrangle from Mars Orbiter Laser Altimeter (MOLA) data. The highest elevations are red and the lowest are blue.
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| Coordinates | 15°00′N 337°30′W / 15°N 337.5°WCoordinates: 15°00′N 337°30′W / 15°N 337.5°W |
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The Arabia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Arabia quadrangle is also referred to as MC-12 (Mars Chart-12).
The quadrangle contains part of the classic area of Mars known as Arabia. It also contains a part of Terra Sabaea and a small part of Meridiani Planum. It lies on the boundary between the young northern plains and the old southern highlands. The quadrangle covers the area from 315° to 360° west longitude and 0° to 30° north latitude.
The surface of the Arabia quadrangle appears to be very old because it has a high density of craters, but it is not near as high in elevation as typical old surfaces. On Mars the oldest areas contain the most craters; the oldest period is called Noachian after the quadrangle Noachis. The Arabia area contains many buttes and ridges. Some believe that during certain climate changes an ice-dust layer was deposited; later, parts were eroded to form buttes. Some outflow channels are found in Arabia, namely Naktong Vallis, Locras Valles, Indus Vallis, Scamander Vallis, and Cusus Valles.
Many places in Arabia are shaped into layers. The layers can be a few meters thick or tens of meters thick. Recent research on these layers by scientists at California Institute of Technology (Caltech) suggest that ancient climate change on Mars caused by regular variation in the planet's tilt, or obliquity may have caused the patterns in the layers. On Earth, similar changes (astronomical forcing) of climate results in ice-age cycles.
A recent study of layers in craters in western Arabia revealed much about the history of the layers. Although the craters in this study are just outside the boundary for the Arabia quadrangle the findings would probably apply to the Arabia quadrangle as well. The thickness of each layer may average less than 4 meters in one crater, but 20 meters in another. The pattern of layers measured in Becquerel crater, suggests that each layer was formed over a period of about 100,000 years. Moreover, every 10 layers were bundled together into larger units. The 10-layer pattern is repeated at least 10 times. So every 10-layer pattern took one-million years to form.
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