Grain size and hydrodynamic sorting controls on the composition of basaltic sediments: Implications for interpreting martian soils

摘要: Abstract Impact shattering of bedrock and wind-driven sorting have been identified as primary processes modifying the size, shape, roundness basalt-derived sediments at Spirit rover landing site in Gusev Crater, Mars. We experimentally explore how physical can cause significant compositional modification sediment relative to absence chemical weathering. Two basalt samples, chosen provide a range source rock compositions textures, were crushed sieved. quantify variations mineral proportions function grain well accompanying changes major- trace-element geochemistry. Redistribution phenocrysts imposes control on sediments, although minor fractionations affect concentrations. Olivine accumulation pairs with increasing MgO, Fe 2 O 3 (T), Ni, Co, Al depletion. The observed physically sorted our experiments mimic those measured martian soils. Aeolian transport models demonstrate that components basalts under conditions is likely. Given potential for by winds Mars we argue must be considered, addition weathering, when interpreting geochemical sediments.