Garden of the Gods at Colorado Springs: Paleozoic and Mesozoic Sedimentation and Tectonics

摘要

Exposed along the southeast fl ank of the Colorado Front Range are rocks that beautifully illustrate the interplay of sedimentation and tectonics. Two major rangebounding faults, the Ute Pass fault and the Rampart Range fault, converge on the Garden of the Gods region west of Colorado Springs. Cambrian through Cretaceous strata upturned by these faults reveal in their grain compositions, textures, and bedforms radically different styles of sedimentation. The Cambrian/Ordovician marine transgressive deposits appear to have come to rest on a passive and tectonically inactive craton. In contrast, coarse-grained Pennsylvanian/Permian marine deposits of the Fountain Formation and Lyons Sandstone reveal deposition by suspension and tractive currents in a very dynamic tectonic setting. These styles are contrasted with the alternating eustatics of the Western Interior Seaway which led to the local Cretaceous section. Finally, the powerful imprint of the Laramide orogeny is evident in the sandstone dikes of Sawatch Sandstone which are found within the hanging wall of the Ute Pass fault.