Phaethontis quadrangle
Map of Phaethontis quadrangle from Mars Orbiter Laser Altimeter (MOLA) data. The highest elevations are red and the lowest are blue.
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| Coordinates | 47°30′S 150°00′W / 47.5°S 150°WCoordinates: 47°30′S 150°00′W / 47.5°S 150°W |
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The Phaethontis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Phaethontis quadrangle is also referred to as MC-24 (Mars Chart-24).
The name comes from Phaethon, the son of Helios.
The Phaethontis quadrangle lies between 30° and 65 ° south latitude and 120° and 180 ° west longitude on Mars. This latitude range is where numerous gullies have been discovered. An old feature in this area, called Terra Sirenum lies in this quadrangle; Mars Reconnaissance Orbiter discovered iron/magnesium smectites there. Part of this quadrangle contains what is called the Electris deposits, a deposit that is 100–200 meters thick. It is light-toned and appears to be weak because of few boulders. Among a group of large craters is Mariner Crater, first observed by the Mariner IV spacecraft in the summer of 1965. It was named after that spacecraft. A low area in Terra Sirenum is believed to have once held a lake that eventually drained through Ma'adim Vallis. Russia's Mars 3 probe landed in the Phaethontis quadrangle at 44.9° S and 160.1° W in December 1971. It landed at a speed of 75 km per hour, but survived to radio back 20 seconds of signal, then it went dead. Its message just appeared as a blank screen.
The Phaethontis quadrangle is the location of many gullies that may be due to recent flowing water. Some are found in the Gorgonum Chaos and in many craters near the large craters Copernicus and Newton (Martian crater). Gullies occur on steep slopes, especially on the walls of craters. Gullies are believed to be relatively young because they have few, if any craters. Moreover, they lie on top of sand dunes which themselves are considered to be quite young. Usually, each gully has an alcove, channel, and apron. Some studies have found that gullies occur on slopes that face all directions, others have found that the greater number of gullies are found on poleward facing slopes, especially from 30-44 S.
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