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  • Elevation Anomalies of the ...
    Annex, A. M.; Ehlmann, B. L.

    Geophysical research letters, 28 March 2024, Letnik: 51, Številka: 6
    Journal Article

    We reassessed several orbital topographic data sets for the Perseverance rover landing site at Jezero Crater, Mars to better understand its floor units. Tens‐of‐meters deep topographic anomalies occur in the volcanic floor of Jezero crater and are not a result of impact cratering. Eight km‐scale steep escarpment‐bounded depressions may be locations of paleotopographic highs that were embayed by the volcanic floor lava flows, forming inverted topography from either contemporaneous upward inflation of embaying lavas or later deep scour due to differential erosion over 107−9 years. Five multi km‐scale shallow‐sloped depressions linked by channel‐like forms may record locations of buried paleolakes and channels that predate the volcanic floor units or a drained magma system. These results indicate Jezero experienced multiple closed‐basin or dry phases, allowing erosion of the crater floor and creation of topography, which provides new geologic context for the samples gathered by Perseverance. Plain Language Summary The Perseverance rover has been on Mars in Jezero Crater for over 2 years collecting rock samples. We reexamined elevation data to better understand the volcanic lava unit on the floor of the crater. We found that the floor is slightly tilted south‐southeast, possibly due to sediment, sourced from the north, beneath the volcanic floor. In the floor we found eight depressions bounded by cliffs, possibly formed by past lava flows around hills of weaker rocks that are now eroded away or by the lavas rising upward around the hills of rock. We also found five large, shallow depressions connected by channels. These might indicate old locations of lakes and rivers before the more recent volcanic activity or a drained magma system. This suggests Jezero Crater experienced alternating phases of being dry and being filled with water, providing key information to help interpret the collected samples. Key Points Tens‐of‐meters deep topographic anomalies occur in the volcanic floor of Jezero Crater Several multi‐km2 scale shallow‐sloped depressions and channels may record lower lake levels or a drained magma system Eight escarpment‐bounded depressions formed by lava embayment of preexisting topography followed by lava inflation or differential erosion