MAPPING THE TERRA SIRENUM REGION: WINDOW INTO PRE-THARSIS AND THARSIS PHASES OF MARS EVOLUTION

Detailed structural mapping is vital to unraveling the geologic and tectonic histories on Earth and Mars. For example, maps delineating tectonic structures of various ages can be used to characterize potential stress sources, strain magnitudes and fault histories, as well as pre-existing structural controls that may relate to episodes of local or regional tectonism. For western Mars, the formation of the Tharsis rise dominated the geologic and tectonic histories. The Terra Sirenum region is an area that was heavily affected by the formation of the Tharsis rise. This region is located on the southwestern flanks of the Tharsis and is centered at 39.7°S and 210°E. Due to its pronounced location, this region holds the key for understanding of the timing of the major fault systems associated with the formation of the Tharsis rise. Five major fault systems are linked with the southern region of Tharsis. Of these five major fault systems, three have been identified within the Terra Sirenum region: Memnonia Fossae, Sirenum Fossae, and Icaria Fossae. Detailed examination of these structures within this region provides an excellent window into identifying the tectonic processes that influenced the geologic evolution of the western hemisphere region. In this meeting, we plan on presenting our 1:5,000,000-scale geologic map of the Terra Sirenum region of Mars, displaying the complex, crosscutting relationship among several of the fault systems and provide a glimpse of the early history of Mars.