Lobate debris aprons

Lobate debris aprons (LDAs) are geological features on Mars, first seen by the Viking Orbiters, consisting of piles of rock debris below cliffs. These features have a convex topography and a gentle slope from cliffs or escarpments, which suggest flow away from the steep source cliff. In addition, lobate debris aprons can show surface lineations as do rock glaciers on the Earth.

Wide view of mesa with CTX showing Cliff face and location of lobate debris apron (LDA) Location is Ismenius Lacus quadrangle.

Enlargement of previous CTX image of mesa This image shows the cliff face and detail in the LDA. Image taken with HiRISE under HiWish program. Location is Ismenius Lacus quadrangle.

Lobate debris aprons (LDAs) around a mesa, as seen by CTX. Mesa and LDAs are labeled so one can see their relationship. Radar studies have determined that LDAs contain ice; therefore, these can be important for future colonists of Mars. Location is Ismenius Lacus quadrangle.

Close-up of lobate debris apron (LDA), as seen by HiRISE under HiWish program

Lobate debris apron in Phlegra Montes, as seen by HiRISE. The debris apron is probably mostly ice with a thin covering of rock debris, so it could be a useful source of water. Scale bar is 500 meters long.

Close-up of surface of a lobate debris apron in Hellas quadrangle. Note the lines that are common in rock glaciers on the Earth.

View of a lobate debris apron along a slope in Arcadia quadrangle.

Place where a lobate debris apron begins. Note stripes which indicate movement. Image located in Ismenius Lacus quadrangle.

The Mars Reconnaissance Orbiter's Shallow Radar gave a strong reflection from the top and base of LDAs, meaning that pure water ice made up the bulk of the formation (between the two reflections). This is evidence that the LDAs in Hellas Planitia are glaciers covered with a thin layer of rocks.

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