Amazonian Hydrothermal Activity in Ladon Basin, Mars: Listwanitization of Serpentinized Lava Flows?

Kurzfassung

Listwanite, an assemblage of serpentine, carbonates, quartz and other minerals, is found in obducted oceanic crust, in the context of intense hydrothermal circulation (e.g., [1]). We analyzed CaSSIS, HiRISE, CRISM, and CTX data of the eastern Ladon basin, and found that serpentinization and carbonation of late Hesperian to Early Amazonian ultramafic lava flows is generally consistent with the presence of listwanite ridges. Study area: The Ladon basin hosts Late Noachian and Hesperian sediments from a multistage drainage system [2], though to have fed a relict groundwater system [3]. Floor-fractured craters (FFCs) formed later, and are filled by a unit that extends beyond them as a graben- and wrinkle-ridge-bearing unit. FFC fracturing has been attributed to magmatic inflation and deflation episodes, perhaps associated with groundwater migration [4, 5]. The study area is located in such a unit where three layers are exposed and provide a modelled age of upper Hesperian to lower Amazonian.