Transient Hydrology in Amazonis Planitia (Mars) in the Aftermath of the Tooting Impact

Hydrological flows generated by meteoroid impact are still largely unexplored on Mars and may also have implications for Earth. We reconstructed the hydrological sequence initiated on Mars by a less than 3 Ma old meteoroid impact that formed the 28 km-wide Tooting crater on Amazonis Planitia, an ice-bearing region. Significant thermal and mechanical erosion were produced by the temporary rivers created by the impact on the icy terrain. Through analysis of CTX and HiRISE imagery supplemented with hydrological calculations, we inferred that the meltwater flowed approximately 80 km, eroding deeply the soil. Upon encountering an extensive (more than 100 km) impact-induced fracture line network, the water plummeted in vertical waterfalls, creating thermokarst caverns and ephemeral lakes. Secondary water springs are hypothesized to stem from the impact of ballistic ejecta blocks. Our analysis reveals that the initial hydrologic activity took a short time (hours to one day), while thermal effects were more durable but still geologically rapid. HiRISE imagery reveals slope streaks inside the emptied lacustrine basins. Lines, which emerge from a deep regolith layer, are potentially indicative of aquifer-fed water springs. The consistent origination of multiple lineae at the same stratigraphic level hints at significant subsurface re-mobilized water or ice, when heat was released from temporary warm lakes.