EXPLORING THE SEDIMENTARY ROCK RECORD OF MARS: INSIGHTS GAINED FROM THE OPPORTUNITY AND CURIOSITY ROVERS

Our knowledge of the Martian sedimentary rock record has increased dramatically over the last decade. Observations from the Opportunity and Curiosity rovers have shown that Mars has a rich sedimentary history, preserving evidence for ancient eolian, fluvial, and lacustrine environments. These roving field geologists have been able to carry out investigations that rival the level of detail available in terrestrial sedimentology. For example, rover-scale observations enable scientists to log sedimentary sections, identify facies associations, perform grain-scale analyses, conduct clast surveys, characterize diagenetic features, reconstruct eolian and fluvial architecture, measure paleoflow directions, and make estimates of flow depth and velocity. Through these observations, our view of Mars as primarily a volcanic planet has shifted to Mars as a planet with a complex sedimentary history. The Opportunity rover has explored a variety of sedimentary deposits, including eolian sandstones and subaqueous interdune deposits across the Meridiani plains, and impact breccias and fine-grained layered rocks exposed along the rim of Endeavour crater. Meanwhile, the Curiosity rover has investigated fluvial conglomerates, cross-bedded fluvial sandstones, delta clinoforms, and lacustrine mudstones across Bradbury Rise and the lower reaches of Aeolis Mons. Presented here is an overview of sedimentary environments explored by the Opportunity and Curiosity rovers, and discussion of new advances in extraterrestrial sedimentology with an eye towards upcoming missions.