Prow & co.: inside the fluvial lenses of Gale's layered sulfate unit
Résumé
For three years, the Curiosity rover has been exploring the layered sulfate unit (LSu) of Gale crater, Mars. Not only interesting as a potential record of a monotonic environmental shift towards arid conditions at the Noachian-Hesperian transition, we now know that this interval evidences complex environmental parameters which are characterized by alternating wetter and drier conditions at various timescales [1-3]. Such changes in depositional setting are particularly apparent within the Contigo mbr. of the Mirador fm. There, the LSu strata is dominated by stacked, large-scale cross-stratified aeolian sandstones, tens of meters in thickness, that are punctuated by erosion-resistant, decameter-wide, darker-toned and mostly lens-shaped sandstone bodies that suggest a fluvial deposition [4]. Using image data acquired with Mastcam and ChemCam’s RMI, we detail a wealth of sedimentary structures distributed across these lenses, focusing at the Prow outcrop and neighboring buttes (Fig. 1). We also provide a first assessment of the chemical compositions seen by ChemCam’s LIBS at the Prow.
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