The Mars 2020 Perseverance Rover’s Exploration of the Sedimentary Rock Record in Jezero Crater, Mars

NASA’s Mars 2020 Perseverance rover has explored and sampled sedimentary and igneous rocks deposited within the 45 km Jezero impact crater, located in a compositionally diverse, ancient region of Mars. This open-system paleolake was selected as Perseverance’s landing site because of its diverse intracrater record, including a well-preserved sedimentary fan and carbonate-bearing deposits along the inner crater margin.

The basal sequence of the western fan, informally named the “Shenandoah” formation, is comprised of mudstones, sandstones, and granule-pebble conglomerates unconformably overlying igneous rocks. This formation records the transition from a likely distal alluvial fan setting to a laterally extensive (~km scale) lake. The overlying “Tenby” formation is comprised of sets up to ~25 meters thick of carbonate-bearing, sand-dominated, steeply dipping beds overlain by coarse-grained, cross-stratified lenses of sandstone and boulder conglomerates. The Tenby formation is interpreted as a fluvio-deltaic sequence of downstream accreting bars and deltaic foresets. A dense accumulation of pyroxene- and olivine-bearing boulders cover the upper surface of the Tenby formation. In plan-view, boulder accumulations occur as a series of cross-cutting channel bodies that likely represent transport by late-stage high energy floods into the crater.

Perseverance has sampled seven unique aqueously deposited sedimentary rocks for potential future return to Earth as part of the Mars Sample Return Campaign. These samples will constrain the timing and duration of aqueous activity on Mars, its climate and habitable paleoenvironments, and enable the search for past martian life.