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Brine-driven destruction of clay minerals in Gale crater, Mars
Ist Teil von
Science (American Association for the Advancement of Science), 2021-07, Vol.373 (6551), p.198-204
Ort / Verlag
Washington: The American Association for the Advancement of Science
Erscheinungsjahr
2021
Quelle
American Association for the Advancement of Science
Beschreibungen/Notizen
Modified clay minerals on Mars
Sedimentary rocks exposed in Gale crater on Mars contain extensive clay minerals. Bristow
et al.
analyzed drill samples collected by the Curiosity rover as it climbed up sedimentary layers in the crater. They found evidence of past reactions with liquid water and sulfate brines, which could have percolated through the clay from an overlying sulfate deposit. Similar sulfate deposits are widespread across the planet and represent some of the last sedimentary rocks to form before the planet lost its surface liquid water, so the results inform our understanding of the geologic processes that occurred as Mars dried out.
Science, abg5449, this issue p.
198
Clay minerals examined by the Curiosity rover contain evidence of reactions with sulfate brines as Mars dried out.
Mars’ sedimentary rock record preserves information on geological (and potential astrobiological) processes that occurred on the planet billions of years ago. The
Curiosity
rover is exploring the lower reaches of Mount Sharp, in Gale crater on Mars. A traverse from Vera Rubin ridge to Glen Torridon has allowed
Curiosity
to examine a lateral transect of rock strata laid down in a martian lake ~3.5 billion years ago. We report spatial differences in the mineralogy of time-equivalent sedimentary rocks <400 meters apart. These differences indicate localized infiltration of silica-poor brines, generated during deposition of overlying magnesium sulfate–bearing strata. We propose that destabilization of silicate minerals driven by silica-poor brines (rarely observed on Earth) was widespread on ancient Mars, because sulfate deposits are globally distributed.