Updated orbital perspective of the Mt. Sharp upper sulfates in preparation for in situ exploration

Mg sulfate (MGS) is one of the most common secondary minerals on Mars, with orbital detections spread across the planet and multiple occurrences and elevations within Gale crater. The mineralogy of MGS (including its crystallinity and hydration state) and its geologic setting can be used to place precise limits on aqueous conditions during formation and diagenesis. Both monohydrated Mg-sulfate and polyhydrated Mg-sulfate have been observed in Gale crater from orbit, and the MSL mission is now within the area where MGS-rich strata are identified from orbit, presenting an opportunity to examine these common martian minerals in situ. We map MGS-rich outcrops along the planned rover traverse route and similar stratigraphic range around all of Mt. Sharp. By comparing CRISM and HiRISE data in a restricted stratigraphic range, we identify small features of interest such as potential thin monohydrated MGS layers. As monohydrated MGS cannot have been exposed to liquid water or frost since formation, these are important outcrops for the rover to conduct contact science and gather high-resolution textural observations which can be used to test formation hypotheses.