Paper No. 236-1
Presentation Time: 1:35 PM
CHANGES IN LAKE WATER CHEMISTRY AND DIAGENESIS FROM MINERAL DETECTIONS IN ANCIENT LAKE SEDIMENTS IN GALE CRATER, MARS (Invited Presentation)
The Mars Science Laboratory Curiosity rover landed in Gale crater, Mars in August 2012 to study a portion of a kilometers-thick sedimentary sequence with evidence for Fe/Mg smectite and sulfate minerals from orbit to interpret past aqueous environments and habitability. Curiosity has investigated nearly 500 m of stratigraphy, and many of the rocks Curiosity has encountered have been laminated mudstones interpreted as lacustrine deposits that were deposited over millions to tens of millions of years. CheMin is an X-ray diffractometer on Curiosity and has analyzed drill powders from 27 ancient fluvio-lacustrine outcrops. CheMin analyses demonstrate changes in type and abundance of igneous silicates, SiO2 phases, phyllosilicates, sulfates, Fe-oxides/oxyhydroxides, and carbonates across Curiosity’s traverse. These changes in mineralogy through the stratigraphic section may be a result of changes in sediment source, lake water chemistry, and diagenetic processes spatially and through time. We will present the mineralogy of the fluvio-lacustrine rocks analyzed by CheMin and evaluate the different hypotheses proposed to explain mineralogical variability.