CONSTRAINING MARTIAN SEDIMENTATION VIA ANALYSIS OF STRATAL PACKAGING, INTRACRATER LAYERED DEPOSITS, ARABIA TERRA, MARS

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.