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Near Surface Stratigraphy and Regolith Production in Southwestern Elysium Planitia, Mars: Implications for Hesperian-Amazonian Terrains and the InSight Lander Mission
The presence of rocks in the ejecta of craters at the InSight landing site in southwestern Elysium Planitia indicates a strong, rock-producing unit at depth. A finer regolith above is inferred by the lack of rocks in the ejecta of 10-m-scale craters. This regolith should be penetrable by the mole of...
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Published in: | Space science reviews 2017-10, Vol.211 (1-4), p.147-190 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The presence of rocks in the ejecta of craters at the InSight landing site in southwestern Elysium Planitia indicates a strong, rock-producing unit at depth. A finer regolith above is inferred by the lack of rocks in the ejecta of 10-m-scale craters. This regolith should be penetrable by the mole of the Heat Flow and Physical Properties Package (HP
3
). An analysis of the size-frequency distribution (SFD) of 7988 rocky ejecta craters (RECs) across four candidate landing ellipses reveals that all craters >200 m in diameter and
<
750
±
30
Ma
in age have boulder-sized rocks in their ejecta. The frequency of RECs however decreases significantly below this diameter (
D
), represented by a roll-off in the SFD slope. At
30
m
<
D
<
200
m
, the slope of the cumulative SFD declines to near zero at
D
<
30
m
. Surface modification, resolution limits, or human counting error cannot account for the magnitude of this roll-off. Rather, a significant population of 3 m by the HP
3
however increases significantly due to the increase in boulder-size rocks in the lower regolith column, near the interface of the bedrock. |
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ISSN: | 0038-6308 1572-9672 |
DOI: | 10.1007/s11214-017-0352-x |