Bedrock Geochemistry and Alteration History of the Clay‐Bearing Glen Torridon Region of Gale Crater, Mars
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Bedrock Geochemistry and Alteration History of the Clay‐Bearing Glen Torridon Region of Gale Crater, Mars. / Dehouck, Erwin; Cousin, Agnès; Mangold, Nicolas; Frydenvang, Jens; Gasnault, Olivier; Forni, Olivier; Rapin, William; Gasda, Patrick J.; Caravaca, Gwénaël; David, Gaël; Bedford, Candice C.; Lasue, Jérémie; Meslin, Pierre-Yves; Rammelkamp, Kristin; Desjardins, Marine; Le Mouélic, Stéphane; Thorpe, Michael T.; Fox, Valerie K.; Bennett, Kristen A.; Bryk, Alexander B.; Lanza, Nina L.; Maurice, Sylvestre; Wiens, Roger C.
In: Journal of Geophysical Research: Planets, Vol. 127, No. 12, e2021JE007103, 2022.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Bedrock Geochemistry and Alteration History of the Clay‐Bearing Glen Torridon Region of Gale Crater, Mars
AU - Dehouck, Erwin
AU - Cousin, Agnès
AU - Mangold, Nicolas
AU - Frydenvang, Jens
AU - Gasnault, Olivier
AU - Forni, Olivier
AU - Rapin, William
AU - Gasda, Patrick J.
AU - Caravaca, Gwénaël
AU - David, Gaël
AU - Bedford, Candice C.
AU - Lasue, Jérémie
AU - Meslin, Pierre-Yves
AU - Rammelkamp, Kristin
AU - Desjardins, Marine
AU - Le Mouélic, Stéphane
AU - Thorpe, Michael T.
AU - Fox, Valerie K.
AU - Bennett, Kristen A.
AU - Bryk, Alexander B.
AU - Lanza, Nina L.
AU - Maurice, Sylvestre
AU - Wiens, Roger C.
PY - 2022
Y1 - 2022
N2 - Glen Torridon is a topographic trough located on the slope of Aeolis Mons, Gale crater, Mars. It corresponds to what was previously referred to as the “clay-bearing unit,” due to the relatively strong spectral signatures of clay minerals (mainly ferric smectites) detected from orbit. Starting in January 2019, the Curiosity rover explored Glen Torridon for more than 700 sols (Martian days). The objectives of this campaign included acquiring a detailed understanding of the geologic context in which the clay minerals were formed, and determining the intensity of aqueous alteration experienced by the sediments. Here, we present the major-element geochemistry of the bedrock as analyzed by the ChemCam instrument. Our results reveal that the two main types of bedrock exposures identified in the lower part of Glen Torridon are associated with distinct chemical compositions (K-rich and Mg-rich), for which we are able to propose mineralogical interpretations. Moreover, the topmost stratigraphic member exposed in the region displays a stronger diagenetic overprint, especially at two locations close to the unconformable contact with the overlying Stimson formation, where the bedrock composition significantly deviates from the rest of Glen Torridon. Overall, the values of the Chemical Index of Alteration determined with ChemCam are elevated by Martian standards, suggesting the formation of clay minerals through open-system weathering. However, there is no indication that the alteration was stronger than in some terrains previously visited by Curiosity, which in turn implies that the enhanced orbital signatures are mostly controlled by non-compositional factors.
AB - Glen Torridon is a topographic trough located on the slope of Aeolis Mons, Gale crater, Mars. It corresponds to what was previously referred to as the “clay-bearing unit,” due to the relatively strong spectral signatures of clay minerals (mainly ferric smectites) detected from orbit. Starting in January 2019, the Curiosity rover explored Glen Torridon for more than 700 sols (Martian days). The objectives of this campaign included acquiring a detailed understanding of the geologic context in which the clay minerals were formed, and determining the intensity of aqueous alteration experienced by the sediments. Here, we present the major-element geochemistry of the bedrock as analyzed by the ChemCam instrument. Our results reveal that the two main types of bedrock exposures identified in the lower part of Glen Torridon are associated with distinct chemical compositions (K-rich and Mg-rich), for which we are able to propose mineralogical interpretations. Moreover, the topmost stratigraphic member exposed in the region displays a stronger diagenetic overprint, especially at two locations close to the unconformable contact with the overlying Stimson formation, where the bedrock composition significantly deviates from the rest of Glen Torridon. Overall, the values of the Chemical Index of Alteration determined with ChemCam are elevated by Martian standards, suggesting the formation of clay minerals through open-system weathering. However, there is no indication that the alteration was stronger than in some terrains previously visited by Curiosity, which in turn implies that the enhanced orbital signatures are mostly controlled by non-compositional factors.
U2 - 10.1029/2021JE007103
DO - 10.1029/2021JE007103
M3 - Journal article
VL - 127
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
SN - 0148-0227
IS - 12
M1 - e2021JE007103
ER -
ID: 330736006