Reconstructing the infilling history within Robert Sharp crater, Mars: Insights from morphology and stratigraphy

Abstract

Recent mineralogical studies suggest past aqueous activities in the 150-km-wide Robert Sharp impact crater, the western neighbor of Gale crater on Mars. Despite their mineralogical similarities, Robert Sharp and Gale craters display very different morphologies. Using high-resolution orbital images, we made morphological and stratigraphical analyses, as well as age determinations showing that Robert Sharp has experienced a complex geological history. This includes the formation of fretted terrain and the deposition of airfall material during the early - middle Hesperian epoch. The presence of valleys, fan deltas, and numerous aqueous minerals indicates fluviolacustrine episodes during the Hesperian epoch that persisted episodically until the Amazonian epoch between 1.3 Ga and 500 Ma. Thus, Robert Sharp and Gale craters have experienced contemporaneous aqueous phases possibly up to two billions years after the lacustrine environment recorded by the Curiosity rover within Gale crater.