Planum Australe

As Planum Australe (Latin: " the southern level " ), the plane area of ​​southern Marspols is called. It extends from about the 75th degree of latitude south and has a length of 1600 km at a width of about 1200 km. Its center is located at 83.9 ° S and 160.0 ° E. The geology of this region was originally by NASA 's Mars Polar Lander are examined, this failed, however, because the contact with the probe when lost in the Mars atmosphere entry was.

Icecap

The Planum Australe is partly offset by a permanent, approximately 3 km thick polar ice cap, which consists of frozen water and carbon dioxide. During the Martian winter forms on this permanent addition, a seasonal ice cap that extends from 60 ° S to the south. At the height of winter it reaches a thickness of about one meter. It is possible that the range of this ice cap due to local climate changes temporarily shrinks but then re-expand.

In 1966, the scientists Leighton and Murray presented the assumption that the polar caps of Mars could constitute a reservoir of CO2, their capacity would be under circumstances substantially greater than the atmospheric reservoir. But in the meantime, it is assumed that both poles consist primarily of water ice and are only covered with a thin blanket from years of temporal CO2. Here, the southern pole retains a permanent rest of his CO2 blanket, which is about 8 to 10 feet thick and rests on a foundation of water ice. The assumption that the majority of the ice must be composed of water, is the fact that CO2 ice is not mechanically strong enough to hold a 3-km thick ice sheet over long periods of stable can ..

The data from the Mars Express ESA show that the ice cap can essentially be divided into three sections of different ice conditions. The most reflective part of the ice cap consists of about 85 % of dry ice and 15% water ice. The second section, on which the ice forms on the border surrounding plains, steep slopes, composed almost entirely of water ice. The ice cap is finally surrounded addition of permafrost fields that extend away from the cliffs over tens of kilometers to the north.

The center of the permanent ice cap is not located at 90 ° S, but about 150 kilometers north of the geographic South Pole. The presence of two massive impact basin in the Western Hemisphere - Hellas Planitia and Argyre Planitia - generate an immobile area deeper pressure on the permanent ice cap. The resulting weather patterns lead to the formation of soft white snow, which brings a high albedo with it. This is in contrast to the Schwarzeis that determines the eastern part, where there is little snow descends.

Characteristics

General characteristics

The Planum Australe basically consists of two areas - the Australe lingula (on the imaged relief map than the upper foothills to recognize ) and the Promethei lingula (seen on the map as the one pictured center right foothills, which is bounded from above and below canyons ). Both sections are each traversed by ravines called Promethei Chasma, Ultimum Chasma Chasma Australe and as Australe sulci. It is assumed that these canyons were formed by katabatic winds. The largest crater in the Planum Australe is the 20 km wide crater at McMurdo -84.5 ° S and 0.9 ° E on ( in the height image top ) edge of the plain.

Geysers on Mars

In the images from Mars Global Surveyor was discovered in the dune fields of the south polar region a few dark spots, which come up with the changing seasons and seem to disappear. This phenomenon, which is called the Dark Dune Spots, some scientists explained by a fruit are in season freezing and thawing of the southern ice cap results in the formation of spider-like radial channels that are in the one -meter-thick ice formed by the sunlight.

A group of researchers led by Hugh Kieffer, the United States Geological Survey in Flagstaff, Arizona, suggests that the stains and other unexplained properties of violent water jets are caused from carbon dioxide gas, break through the overlying layer of frozen CO2 and in up to 100 meters high fountain erupt. Due to the sublimation of CO2 - and possibly the water - increases the pressure inside the ice sheet, which could often come to geyser-like eruptions of cold liquid in conjunction with dark basalt, sand or mud. This process takes place rapidly and may a few days, weeks or months last long, one in geology unusually long period. The fact is that these spots seem to appear often on a spider-like groove pattern that is seen in the pictures of the south polar region of Mars. A more detailed exploration of this region is not provided in the current plans.