Detection of Copper by the ChemCam Instrument Along Curiosity's Traverse in Gale Crater, Mars: Elevated Abundances in Glen Torridon
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Laser-Induced Breakdown Spectroscopy, as utilized by the ChemCam instrument onboard the Curiosity rover, detected enhanced abundances of the element copper. Since landing in Gale crater (August 6, 2012) 10 enhancements in copper abundance were observed during 3007 Martian days (sols) of rover operations and 24 km of driving (as of January 20, 2021). The most prominent ones were found in the Kimberley area on the crater floor (Aeolis Palus) and in Glen Torridon on the lower flanks of Aeolis Mons (Mt. Sharp). Enhancements in copper record the former existence of modestly acidic and oxidizing fluids, which were more oxidizing in Kimberley than in Glen Torridon. Of the two main types of bedrock in the lowest part of Glen Torridon, Mg-rich ‘coherent’ and K-rich ‘rubbly’ (named based on their outcrop expression), copper was only detected in coherent, not in rubbly bedrock. The difference between these two types of bedrock may be due to difference in provenance. Alternatively, based on a recently developed lacustrine-groundwater mixing model, we suggest that rubbly bedrock was altered by modestly acidic, shallow-subsurface lake water that leached out both copper and manganese, while coherent bedrock was affected by dominantly alkaline fluids which would be consistent with its mineralogical composition (including siderite) as returned by the CheMin instrument onboard the rover. Higher up in Glen Torridon, ChemCam data indicated significant gradients in copper concentration in coherent bedrock on a local scale of only few meters, which suggests a different alteration style and possibly different types of diagenetic fluids.
|Journal||Journal of Geophysical Research: Planets|
|Number of pages||23|
|Publication status||Published - 2023|