The Antarctic Dry Valleys represent a unique analog for Mars as they are extremely cold and dry deserts. The chemistry of sediment and soil samples from Taylor and Wright Valleys were analyzed (e.g. Bishop et al. 2001; Englert et al. 2012) showing that elevated salt levels are present a few cm below the surface (e.g. Gibson et al. 1983). SO42-, Cl-, and NO32- anions were detected in these samples and gypsum was found by XRD. Salt concentrations are compared with SiO2 abundance for 4 samples collected at different depths in a soil pit from the Wright Valley (Figure 1). Reflectance spectra of these 4 samples (Figure 2) are compared with spectra of salt minerals (selected sulfates-gold,green; phosphates-brown, nitrates-pink and perchlorates-purple). Gypsum plus montmorillonite or hydrated silica appear to be present in most samples based on the spectral features. Additional hydrated salt components could be contributing to the 2.44 μm band and the 2.09 μm shoulder. The sulfur values for some surface and shallow depth samples are similar in magnitude to Mars Exploration Rover soil and rock sulfur abundances. Prospect Mesa pit #1 and Don Juan Pond area samples have concentrations as high as 2.2% and 6.2% S (15.5% SO3 equivalent). Figure 1. Figure 2: Reflectance spectra of 4 soil pit samples compared to spectra of Al/Si-OH species (montmorillonite and opal) and salts.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- 1039 GEOCHEMISTRY / Alteration and weathering processes;
- 5470 PLANETARY SCIENCES: SOLID SURFACE PLANETS / Surface materials and properties