[PLS] Emmy Hughes (CU Boulder)

Since its arrival at Gale crater in 2012, the Curiosity rover has climbed hundreds of meters of stratigraphy representing the diverse environments of ancient Mars. Along its traverse, Curiosity has identified clay-rich lacustrine environments transitioning up-section to salt-rich aeolian environments. Such strata appear to represent a drying sequence, echoed by similar sequences across Mars, which might record information about how and why Mars lost its water. Curiosity has now been exploring the Mg sulfate-rich unit of Gale crater for multiple Earth years and has revealed a diverse set of salts—sulfates, carbonates, and halides—that suggest extensive and prolonged aqueous activity while the region appears to have dried out. The Chemistry and Camera (ChemCam) instrument on board Curiosity has the unique capability of resolving chemical variability within a single rock target as well as variability along the rover traverse. Here, we discuss ChemCam’s observations of salt-rich aeolian bedrock in the layered sulfate-bearing unit (LSU) of Gale crater, including signatures of mixed salts that suggest pore-space reactions in aeolian bedrock, in turn indicating multiple fluid sources, perhaps occurring close to the time of cementation of silicate grains. Ultimately, the LSU may represent numerous aeolian environments with changing water tables and extensive deposition of salts via multiple fluid events. Curiosity’s continued exploration of this intriguing region will no doubt continue to unveil its complicated aqueous history.

Planetary Lunch Seminar —

Colloquia topics span the range of research interests of the department’s planetary sciences research program, and the talks are intended to appeal to any graduate students, postdocs, research scientists, and faculty with a background in planetary science. Speakers include members of the MIT community and visitors.

Contact: planetary-org@mit.edu