Pacing Early Mars Sedimentary Rock Formation

Abstract Mars' sedimentary rock record documents past surface and/or near‐surface liquid water. However, paleoclimate models struggle to explain conditions warm enough for past liquid water. One hypothesis is transient warming by ‐ collision‐induced absorption (CIA) (‐ CIA). This model predicts 5–100 warm climate events, each lasting 100 kyr, however, current constraints on sedimentary rock accumulation timescales are too coarse to test these predictions. We refine depositional timescales at Meridiani Planum and Gale crater using chronology from syndepositional craters, which form from impacts during deposition. We estimate the deposition timespan of Meridiani Planum to range from 114 to 170 Myrs (with uncertainties ranging from 30 to 800 Myrs), compared to previous estimates of 300 Myrs. The distribution of craters within stratigraphy indicate that 4–12 warming episodes occurred. These results are consistent with ‐ CIA and in combination with estimated accumulation rates highlight that sedimentary‐rock‐forming episodes were brief, sporadic, and punctuated by long periods of non‐deposition.