Abstract

Up to 2400 meters of Upper Cretaceous and early Tertiary coarse fluvial and fine-grained paludal Laramide synorogenic sediments are preserved on the east and west sides of the Front Range in central Colorado. On the east side of the Front Range, strata are preserved in the Denver Basin; to the west of the Front Range they occur in the South Park Basin. These strata preserve evidence of the paleo-landscapes present in the region during the uplift of the Front Range, a mountain range defined by the Laramide orogeny. The rock record suggests that the Front Range rose episodically, starting in the latest Cretaceous and continuing through the Eocene. Widespread volcanism characterized the early phase of uplift. After the final pulse of differential uplift, erosion beveled the Front Range basement uplifts and filled in the peripheral basins. Later, regional epirogenic uplift caused streams to incise and exhume physiographic features initially established by Laramide deformation.