DEPOSITION AND DEFORMATION WITHIN EASTERN CANDOR CHASMA, MARS

The Valles Marineris canyon system of Mars contains an extensive sequence of stratified deposits that exceeds 8 km in thickness. Due to their inferred sedimentary provenance, many of these deposits are attractive resources for investigating past depositional, potentially habitable, environments. In this presentation, I report on the results of an investigation into the depositional environments and deformational history of a section of stratified deposits in the eastern Candor Chasma region of Valles Marineris, with the intent of improving current understanding of the region’s geologic history. The following results are based on analyses of digital elevation models (1-m post spacings) and orthorectified image data (0.25 m/pixel) collected by the High Resolution Imaging Science Experiment (HiRISE) camera on board the Mars Reconnaissance Orbiter. The study area lies within the basin formed by Candor Chasma, and encompasses massive rocks that comprise most of Nia Mensa (a large mesa within the basin) and stratified rocks and mass-wasting deposits exposed between Nia Mensa and the northern wall of the basin. These rocks are divided into twelve massive to well-stratified allostratigraphic units. Paleoshorelines and evidence of shorezone reworking of sediments are identified, demonstrating that this part of the basin contained a lacustrine system at least once during its geologic history. Additionally, mud flows, clastic injectites, and contorted bedding are identified in the study area, indicating subsurface mobilization of poorly consolidated to unconsolidated, water-saturated, sediments. These interpretations point to a depositional environment where water played a role in the deposition of at least some sediments. Future work will focus on better constraining the timing of extant surface water in the study area, the role of water in the deposition of other units, and understanding the implications for the potential preservation of biomarkers within these sediments.