| The Soda-Avawatz fault zone (S-AFZ), a dextral shear zone in the Soda Mountains, northwest of Baker, California, lies between the Mojave Desert and Basin and Range structural provinces. Facies analyses of Tertiary fanglomerates of the Avawatz Formation, exposed along the S-AFZ, constrain slip along the S-AFZ and suggest offset across the S-AFZ to be at least 20 km. This model is compared to previously proposed structural models.; Provenance, paleocurrent directions, depositional environments and faulting history indicate that the lower member of the Avawatz Formation was derived from a source area to the south and east. Right-lateral slip along the S-AFZ displaced this source to the south during deposition of the middle member. By contrast, the upper member of the Avawatz Formation was derived from a western source. Transpression within the S-AFZ uplifted a sliver of bedrock of the Soda Mountains through the Avawatz Formation during the Neogene period. |
