Depositional and Diagenetic Sulfates of Hogwallow Flats and Yori Pass, Jezero Crater: Evaluating Preservation Potential of Environmental Indicators and Possible Biosignatures From Past Martian Surface Waters and Groundwaters

Abstract

The Mars 2020 Perseverance rover has examined and sampled sulfate‐rich clastic rocks from the Hogwallow Flats member at Hawksbill Gap and the Yori Pass member at Cape Nukshak. Both strata are located on the Jezero crater western fan front, are lithologically and stratigraphically similar, and have been assigned to the Shenandoah formation. In situ analyses demonstrate that these are fine‐grained sandstones composed of phyllosilicates, hematite, Ca‐sulfates, Fe‐Mg‐sulfates, ferric sulfates, and possibly chloride salts. Sulfate minerals are found both as depositional grains and diagenetic features, including intergranular cement and vein‐ and vug‐cements. Here, we describe the possibility of various sulfate phases to preserve potential biosignatures and the record of paleoenvironmental conditions in fluid and solid inclusions, based on findings from analog sulfate‐rich rocks on Earth. The samples collected from these outcrops, Hazeltop and Bearwallow from Hogwallow Flats, and Kukaklek from Yori Pass, should be examined for such potential biosignatures and environmental indicators upon return to Earth.

Characterizing Hydrated Sulfates and Altered Phases in Jezero Crater Fan and Floor Geologic Units With SHERLOC on Mars 2020

“…Another possibility is that the Ca-sulfates in the upper fan were formed from the same Ca-, Mg-, and sulfatecontaining fluid that flowed across the fan front and crater floor but the Mg-sulfates in the upper fan were formed in a distinct event(s). This is based on the textural observations that Ca-sulfates in both the upper fan and fan front are often observed in mm-sized white veins, crystals or patches which are interpreted as late-stage diagenetic features (Benison et al, 2024) but the hydrated Mg-sulfates in the upper fan do not necessarily show clear textural associations (Table 3). This is unlike the hydrated Mg-sulfates in the crater floor which are localized to visible white crystals or patches rimmed by carbonates (Corpolongo et al, 2023;Siljeström et al, 2024;Wogsland et al, 2023), interpreted to have been precipitated by sulfate-containing fluids filling the voids (Tice et al, 2022).…”

“…These alteration minerals suggest that the western fan is composed of materials that experienced aqueous alteration by fluid with near-neutral pH in the source region and/or depositional environment. Image observations from the WATSON and ACI cameras on the rover indicate that the Shenandoah formation is a sedimentary unit dominated by sandstone, with siltstone grain sizes observed only in the abraded target Uganik Island (Benison et al, 2024;Stack et al, 2024; Figure 2).…”