Geologic map of the Thaumasia Quadrangle of Mars

The Thaumasia quadrangle lies on the south flank of the Tharsis dome (Hord and others, 1974), a large bulge in the crust of Mars extending more than 5,000 km northward from the center of the quadrangle. This major structure imposes a generally southward slope across the entire quadrangle. Topography along the east-central border of the Thaumasia quadrangle exhibits curved scarps and lowlands concentric with the Argyre basin.