| Summary: | Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata
showing systematic alternation between slope- and cliff-forming units, suggesting either
rhythmic deposition of distinct lithologies or lithologies that experienced differential
cementation. Hypothesized origins of these intercrater layered deposits include
lacustrine, aeolian, volcanic airfall, and impact surge deposition. On Earth, rhythmically
deposited strata can be examined in terms of stratal packaging, wherein the interplay of
tectonics, sediment deposition, and change in base level results in predictable patterns
with respect to changes in the amount of space available for sediment accumulation.
Fundamental differences between tectonic regimes of Earth and Mars demand that
packaging of layered strata primarily reflects changes in sediment influx and base level.
Analysis of stratal packaging may therefore help us understand the relative roles of these
parameters, and provide crucial constraint on martian depositional models.
Rhythmic stratal patterns in Becquerel Crater (7°W 22°N) have been attributed to
astronomical forcing of regional climate. A clear depositional model, however, has yet to
be presented. Here, we reanalyze strata of Becquerel Crater and compare results with
two additional crater successions. Results indicate that, by contrast with Becquerel
Crater, strata within Danielson Crater (7°W 8°N) and an unnamed crater (Crater X;
1.2°W 9°N) do not record hierarchical packaging readily attributable to astronomical
effects, and suggest that regional climate forcing may not be readily applied as a
paradigm for all intracrater deposition. Similarities in depositional style in these three
craters, however, may be linked by a model for sediment accumulation—with potential
links to regional climate—wherein episodic melting of ground ice raised local base level,
stabilized aeolian sedimentation, and resulted in differential cementation of accumulated
strata.
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