Ground penetrating radar observations of the contact between the western delta and the crater floor of Jezero Crater, Mars

Jezero Crater contains a record of the aqueous history and potential habitable conditions on Mars in its preserved delta deposits. NASA's Perseverance Rover is exploring the Jezero Western Delta with a suite of instruments including the RIMFAX ground penetrating radar, which provides continuous subsurface images that probe up to 20 meters below the rover. As Perseverance traversed across the contact between Jezero Crater floor and the delta, RIMFAX detected a distinct discontinuity in the subsurface layer structure. Below the contact boundary are older crater floor units that exhibit discontinuous inclined layering. Above the contact boundary are younger lower delta units that exhibit regular horizontal layering. At one location, there is a clear unconformity between the crater floor and delta layers, which implies that the crater floor experienced a period of erosion prior to the deposition of the overlying delta strata. The regularity and horizontality of the basal delta sediments observed in the radar cross sections indicates that they were deposited in a low-energy lake environment.