Controlling factors of river water stable isotope compositions and middle to late Cenozoic deposition and surface uplift history of the southern Rocky Mountains, U.S.A.

Abstract

The Cenozoic topographic evolution of the Rocky Mountains (Rockies) and Great Plains in the western U.S.A. reflect a combination of mantle geodynamic, crustal deformation and surface erosional processes. This region was near sea-level during the Late Cretaceous and is characterized by high topography and high relief at present. Different hypotheses involving crustal shortening and thickening, mantle dynamic process, and enhanced erosion induced by climate change have been proposed to interpret the Cenozoic surface uplift. The timing and magnitude of surface uplift hold the key to test these different hypotheses. This dissertation identifies the controlling factors of modern river water isotopic lapse rate and latitudinal gradient in the southern Rockies in Wyoming and Colorado, and the Great Plains from south Texas to Nebraska; and examines the depositional processes and reconstructs the paleoelevations of the southern Rockies in Colorado and the adjacent Great Plains in Kansas.