Detailed geological mapping of the fluvial deposits in Magong crater, Xanthe Terra, Mars

Abstract

We present a detailed geological map of Magong Crater in Xanthe Terra, Mars. The ancient crater is situated at the terminus of Sabrina Vallis and hosts sedimentary deposits that were transported through this long and deeply incised valley. The sediments may represent a delta or, alternatively, an alluvial fan. Weak signatures of Fe/Mg-bearing phyllosilicates were detected in the central delta cliff section. A long and narrow, NE-trending topographic ridge is interpreted as a partially exhumed dyke. Numerous ~1 m-thick dark patches are distributed over the entire crater floor and may be remnants of a formerly continuous blanket of volcanic tephra or ash. The overall age of the aqueous sediments is dated to the Late Noachian/Early Hesperian epochs. This applies also to the surrounding highland materials. Highresolution images of the crater floor show a heterogeneous morphology, featuring a large variety of degraded craters and ejecta blankets, honeycomblike depressions and polygonal fractures similar to mud cracks. Apart from the sedimentary deposits, the crater floor is very flat and meets the geological and technical criteria for a future possible landing site.