Flow Field Evolution in Southern Tharsis, Mars: Constraints from Mapping, Morphology, and Impact Crater Distributions

The current investigation of lava flow fields in the southern Tharsis region of Mars includes the generation of detailed flow field maps based on analyses of imaging, topographic, and compositional datasets. Mapping of the flow field is being used to assess flow field development and stratigraphy, to examine flow morphology as an indicator of emplacement processes, to evaluate thermophysical signature in order to interpret composition and degradational history, and to provide relative and absolute age constraints using populations of small, superposed impact craters. Mars Reconnaissance Orbiter CTX images (~5 m/pixel) and Mars Odyssey THEMIS data (100 m/pixel) both provide important insights into physical volcanic processes and allow reconstruction of complex volcanic surfaces, including recognition of a host of small-scale volcanic features and two main lava flow types. Darker, tube/channel fed flows are often younger than thicker, rugged leveed flows; however, the observed diversity and complexity of interactions suggests that lava sources with different eruptive styles and magnitudes were distributed throughout the current study region [22-25°S, 120-124°W] and active contemporaneously. General analogies to terrestrial basaltic volcanoes are evident, with comparable suites and diversity of volcanic features and similarities in flow morphology. The characteristics of the different flow types, their surface morphologies, and interactions with local topography, along with insights from terrestrial analogues, provide important clues for understanding flow rheology and interpreting emplacement styles in this region of Mars.