A SOURCE-TO-SINK SCENARIO FOR THE AEOLIS DORSA REGION (Invited Presentation)

Landscape evolution on solid and subaerial planetary surfaces is fundamentally controlled by atmospheric processes. The results of these processes in turn are encapsulated in planetary sedimentary records. On Mars, these records have been interrogated for decades from orbit and more recently by several landed missions. Analysis of these complementary orbital and in situ data has documented a substantial early history of fluvial transport and lacustrine deposition followed by gigayears of aeolian erosion. Together, these erosional, transport, and depositional processes provide the discrete elements necessary for source-to-sink transportation. However, discernment of a connected source-to-sink system – in which areas of sediment generation are linked to areas of sediment deposition by a transport process and pathway – has remained incomplete. One hypothesis for sedimentary sinks on Mars is as local or regional basins in contrast to the northern lowlands. The Aeolis Dorsa region provides a site to consider this hypothesis. The region is located adjacent to the northern plains and exhibits a substantial early history of fluvial transport, with subsequent volcaniclastic (pyroclastic) deposits identified as an origin of aeolian sand. In this putative source-to-sink scenario, the sediment source is these stratigraphically highest volcaniclastic units. The transport pathways are the exhumed inverted fluvial deposits, which show dark sand of similar mineralogy weathering out. The sink in this scenario is the basin within the volcaniclastic units, ringed by fluvial deposits and underlain by a unit with a fluviolacustrine planform discernible in nighttime infrared data. Uncertainties about this source-to-sink scenario include (i) whether the sand originating from the overlying volcaniclastic units is comparable in origin to the sand in the inverted fluvial deposits, and (ii) whether the nighttime infrared unit extends into the Cerberus plains or is confined within the Aeolis Dorsa region. This study illustrates an avenue for better understanding the extent of delivery of sediments to the northern plains, which in turn provides information on the composition and evolution both of the northern plains evolution and of the southern highlands.