Crater Morphometry on the Mafic Floor Unit at Jezero Crater, Mars: Comparisons to a Known Basaltic Lava Plain at the InSight Landing Site

A secondary objective for the Perseverance rover mission to Jezero crater, Mars, is to collect igneous rocks for analysis on Earth. The mafic crater floor unit (MFU) represents the best candidate. Ten-meter-scale craters on the MFU exhibit rocky ejecta, rims, and slopes that indicate resistant rock. The frequency distribution of these craters is, however, low. Comparisons of MFU craters to craters on a lava plain at the Interior Exploration using Seismic Investigation, Geodesy and Heat Transport mission (InSight) landing site reveal that the MFU lacks a granular regolith. Removal of regolith or exhumation of the MFU explains the rocky crater morphology and low density. Erosion rates, calculated using crater retention timescales of ~2.0 Ga for both locations, are 10⁻³ to 10⁻⁴ m/Myr. The rates derive from craters impacted into rocky materials on the MFU versus regolith at InSight. The difference in material strength, yet comparable erosion rates, requires more vigorous surface processes at Jezero relative to global averages on Mars.