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

• Main Author: Cadieux, Sarah Beth
• Format: Others
• Published: Trace: Tennessee Research and Creative Exchange 2011
• Subjects: Mars; Sedimentology; Stratigraphy; Arabia Terra; Layering; Geology; Physical Processes
• Online Access: http://trace.tennessee.edu/utk_gradthes/860

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.