Bedrock Geochemistry and Alteration History of the Clay‐Bearing Glen Torridon Region of Gale Crater, Mars

Abstract

 The Curiosity rover explored Glen Torridon, a section of Aeolis Mons previously referred to as the "clay-bearing unit" of Gale crater  Bedrock compositions measured by ChemCam show variations correlated with changes in outcrop expression and with diagenetic overprint  The relatively strong clay mineral signatures detected from orbit over Glen Torridon are not caused by a greater intensity of alteration

Orbital and In‐Situ Investigation of Periodic Bedrock Ridges in Glen Torridon, Gale Crater, Mars

“…ChemCam results are consistent with the APXS analyses and show two compositionally distinct classes of bedrock and clast targets throughout Glen Torridon characterized primarily by high K/low Mg or low K/high Mg (Dehouck et al., 2022 ). Dehouck et al.…”

“…Dehouck et al. ( 2022 ) observe similar enrichments in K 2 O and SiO 2 for both “rubbly bedrock” within the Glen Torridon Jura and the abundant clasts throughout the area found in the troughs between ridges and on the flanks of the ridges themselves. This enrichment in K 2 O may be due to the presence of the clay mineral illite (Cousin et al., 2021 ).…”

“…This enrichment in K 2 O may be due to the presence of the clay mineral illite (Cousin et al., 2021 ). Coherent bedrock within the Glen Torridon Jura, likely what is represented in the “Aberlady” and “Kilmarie” drill samples, tends to show higher MgO and lower K 2 O (Dehouck et al., 2022 ).…”

From Lake to River: Documenting an Environmental Transition Across the Jura/Knockfarril Hill Members Boundary in the Glen Torridon Region of Gale Crater (Mars)

“…This difference could reflect a less pronounced aqueous alteration of facies B material. However, the values of the Chemical Index of Alteration are similar for the Types 1 and 2 endmembers (Dehouck et al., 2022). Alternatively, the difference in composition could be due to a difference in sediment provenance, with facies A material being derived from a more K‐rich source.…”

“…The “rubbly” endmember shows a K 2 O‐rich (>1.5 wt.%) and MgO‐poor (usually <6 wt.%) composition, defined as the regional Type 2 composition by Dehouck et al. (2022). The “coherent” endmember shows higher MgO content (∼6–11wt.%) and a lower K 2 O content (<1.5 wt.%) defined as the regional Type 1 composition by Dehouck et al.…”