We analyze Kodiak, an eroded delta remnant in Jezero Crater, Mars, using several hundred images from the Mastcam-Z and SuperCam instruments on the Mars 2020 Perseverance Rover. We create a high-accuracy digital terrain model to measure Kodiak’s stratigraphic layers, which we divide into three units and characterize individually. While each unit possesses geometries interpreted as consistent with a Gilbert-style delta formation, the older units exposed on Kodiak’s north to northeast sides include more complex layered structures with azimuthally varying foresets. We compare Kodiak’s northeast foresets with the clinoforms of Whale Mountain, an outcrop exposed in the Western Jezero Delta scarp, and show similar azimuthally varying foresets. The stratigraphic analysis presented herein (strike and dip, unit thickness, etc.) will help test and refine detailed sedimentological hypotheses for the formation and evolution of the Jezero delta. Our 3D reconstruction and measurements enable unprecedented precision to evaluate depositional models and advance geological interpretation.

Early observations from the Perseverance rover suggested a deltaic origin for the western fan of Jezero crater only from images of the Kodiak butte. Here, we use images from the SuperCam Remote Micro-Imager and the Mastcam-Z camera to analyze the western fan front along the rover traverse, and further assess its depositional origin. Outcrops in the middle to lower half of hillslopes are composed of planar, inclined beds of sandstone that are interpreted as foresets of deltaic deposits. Foresets are locally structured in ~20-25 m thick, ~80-100 m long, antiformal structures interpreted as deltaic mouth bars. Above these foresets are observed interbedded sandstones and boulder conglomerates, interpreted as fluvial topset beds. One well-preserved lens of boulder conglomerate displays rounded clasts within well-sorted sediment deposited in fining upward beds. We interpret these deposits as resulting from lateral accretion within fluvial channels. Estimations of peak discharge rates give a range between ~100 and ~500 m3.s-1 consistent with moderate to high floods. By contrast, boulder conglomerates exposed in the uppermost part of hillslopes are poorly sorted and truncate underlying beds. The presence of these boulder deposits suggests that intense, sediment-laden flood episodes occurred after the deltaic foreset and topset beds were deposited, although the origin, timing, and relationship of these boulder deposits to the ancient lake that once filled Jezero crater remains undetermined. Overall, these observations confirm the deltaic nature of the fan front, and suggest a highly variable fluvial input.