Trends In Mineralogy and Grain Size Distribution Across Paleolake Basins on Earth and Mars

Abstract:

Basins on Mars and Earth are geologically important because they serve as sinks for fluids and sediments over areas much larger than themselves. Due to this characteristic, basins show significant material diversity, with deposits that span long periods of time and layered sediments that may hold clues to conditions of ancient Martian environments. Paleolake basins have, in fact, been the focus of most Martian rover missions due to their importance. Here we aim to characterize the fundamental material properties and trends of paleolake basins through several different means. To achieve this, we use remote sensing spectroscopy (VNIR/IR) and thermophysical modeling along transects of select Martian and terrestrial basins. Additionally, laboratory analysis is being conducted on the terrestrial basins to allow for a better understanding of the factors that could lead to misinterpretation or distortion of data. These results can be extended to remote sensing data collected from Martian paleolake basins. Through this work, significant progress toward three questions is being made: (1) How does mineralogy and grain size distribution change across a paleolake basin? (2) How does post-aqueous sediment deposition and alteration affect analyses of these properties in remote sensing data? (3) How can knowledge of obscuring materials contribute to interpretation and error quantification of remote sensing basin studies on Mars? The joint mineralogical and thermophysical characteristics of basins, and the consistent trends observed provide important constraints on addressing the aforementioned questions. For example, we observe that at Gale crater phyllosilicates can be found throughout the basin, whereas at Jezero crater phyllosilicates are predominantly in the fan deposits. Furthermore, Jezero crater shows carbonates throughout the basin, which is expected because carbonates may also be present as a component of the ubiquitous Martian dust. Clays, olivine, and smectites are also found within fan deposits of Jezero, but are found within the sedimentary sequence of Gale’s inner Aeolis Mons. Additional research pertaining to the differences between these craters will unlock further clues of early Martian climates and advance knowledge of Mars’ past habitability.