Hellas Quadrangle - Lobate Debris Aprons

Lobate Debris Aprons

One very important feature common in east Hellas are piles of material surrounding cliffs. The formation is called a Lobate Debris Apron (LDA's). Recently, research with the Shallow Radar on the Mars Reconnaissance Orbiter has provided strong evidence that the LDA's are glaciers that are covered with a thin layer of rocks. Large amounts of water ice are believed to be in the LDA's. Available evidence strongly suggests that the eastern part of Hellas accumulated snow in the past. When the tilt (obliquity) of Mars increases the southern ice cap releases large amounts of water vapor. Climate models predict that when this occurs, water vapor condenses and falls where LDAs are located. The tilt of the earth changes little because our relatively large moon keeps it stable. The two tiny Martian moons do not stabilize their planet, so the rotational axis of Mars undergoes large variations. Lobate Debris Approns may be a major source of water for future Mars colonists. Their major advantage over other sources of Martian water are that they can easily mapped from orbit and they are closer to the equator where manned missions are more likely to land.

• Close-up of surface of a Lobate Debris Apron. Note the lines that are common in rock glaciers on the Earth. Image located in Hellas quadrangle.

• CTX Context image for next two images of debris apron around mound.

• Surface of Debris Apron. There is also a feature similar to features in Red Rocks Park Colorado. Feature seems to be composed of slanted rock layers. Image taken with HiRISE, under the HiWish program.

• Surface of debris apron in Terra Cimmeria, as seen by HiRISE, under the HiWish program. Colored parts may be frost deposits.