Biosignature Preservation Potential of Sulfate-Rich Rocks From Hogwallow Flats, Jezero Crater, Mars

The Mars 2020 Perseverance Rover discovered fine grained sedimentary rocks in the Hogwallow Flats member of the Shenandoah Formation at the ~3.6- to 3.8-billion-year-old Jezero crater, Mars. Mudstones and sandstones at the 3-meter-thick Hogwallow Flats (HWF) outcrop, and a laterally equivalent outcrop known as “Yori Pass”, show extensive evidence of diagenesis (alteration after deposition). Enhanced preservation of organic matter and other biosignatures can occur in early diagenetic environments associated with aqueous alteration in a lake, floodplain or pro-deltaic setting, as envisaged for HWF and Yori Pass [1]. Three drilled rock cores were collected from HWF-type bedrock as part of the Mars Sample Return Program. They are considered to be the samples with the highest potential to preserve organic compounds and biosignatures out of all samples collected so far by Perseverance (as of mission Sol 1000) [2]. This work outlines the implications of diagenesis for biosignature preservation in rock samples for possible return to Earth.