Great unconformity, Grand Canyon, AZ

sedimentary, Grand Canyon National Park, desert, stair-step topography, erosion

Angular Unconformity, Grand Canyon (Pan)

sedimentary, Grand Canyon National Park, desert, red beds

Angular Unconformity, Grand Canyon

sedimentary, Grand Canyon National Park, desert, red beds

Nonconformity. SW Montana

depositional contact, sedimentary, metamorphic, unconformity

Buttress Unconformity, northern Arizona

Buttress Unconformity

Buttress Unconformity, northern Arizona. In buttress unconformities, the younger material
is deposited against the older material, resulting in the apparent truncation of the younger rock. On
closer inspection, however, one can see erosional features along the contact to indicate its depositional
origin. (ID SrU-25)