This past week on Mars, Perseverance made a pit stop near Overlook Mountain to abrade a rock called Old Faithful Geyser. This target is situated within the Western side of the Margin Unit, an area around the upper edge of Jezero Crater that is astrobiologically-interesting due to its abundant carbonate. Carbonate-bearing rocks have been a major scientific focus throughout this campaign, which began with Perseverance entering the Eastern side of the Margin Unit on Sol 915 of the mission (1 sol = 1 day on Mars) in September of 2023, about 240 sols ago, then roving steadily Westward. So far, Perseverance has collected 3 cores from this Unit, including Pelican Point on Sol 923, Lefroy Bay on Sol 942, and Comet Geyser on Sol 1088. Proximity and remote science observations associated with each of these targets have all confirmed the presence of carbonate, but the grains and mineral assemblages in each rock are unique, which may indicate that carbonates in the Eastern and Western parts of the Margin have experienced different formation mechanisms and/or alteration histories. In particular, the team is interested in understanding whether the carbonate-bearing rocks in the West formed through sedimentary, igneous, or volcaniclastic processes.
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