Home / Node / Deanne Rogers Colloquium Abstract (Mar 27, 2019)

Deanne Rogers Colloquium Abstract (Mar 27, 2019)

Interpreting the Rock Record of Early Mars

Hundreds of areally extensive, flat-lying rock exposures, or “rock plains”, are preserved in the ancient terrains of Mars, potentially providing a record of surface processes operating during the first billion years of Martian history. These rock plains had previously been interpreted as degraded lava plains, perhaps similar to flood basaltic provinces on Earth or the lunar mare. But more recent work suggests that these rocks are easily erodible and fine-grained, indicating formation via explosive volcanism, impact processes and/or aeolian/fluvial sediment transport. Deducing a more specific origin beyond that (e.g. airfall ash, fluvial sediments) is ongoing through detailed studies, but the discovery has highlighted the important role of rock physical properties in influencing their exposure, and in influencing orbital-based interpretations of surface age and mineral enrichments. The present-day distribution and characteristics of ancient rock exposures likely arise from a complex interplay of rock physical properties, impact cratering, and wind activity in addition to primary depositional processes, and thus have far-reaching implications for interpreting the rock record of early Mars.