Post-Paleozoic alluvial gravel transport as evidence of continental tilting in the U.S. Cordillera

Abstract

Research Article| September 01, 2003 Post-Paleozoic alluvial gravel transport as evidence of continental tilting in the U.S. Cordillera Paul L. Heller; Paul L. Heller 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Kenneth Dueker; Kenneth Dueker 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Margaret E. McMillan Margaret E. McMillan 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Paul L. Heller 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Kenneth Dueker 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Margaret E. McMillan 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Publisher: Geological Society of America Received: 20 Jul 2002 Revision Received: 24 Feb 2003 Accepted: 18 Mar 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2003) 115 (9): 1122–1132. https://doi.org/10.1130/B25219.1 Article history Received: 20 Jul 2002 Revision Received: 24 Feb 2003 Accepted: 18 Mar 2003 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Paul L. Heller, Kenneth Dueker, Margaret E. McMillan; Post-Paleozoic alluvial gravel transport as evidence of continental tilting in the U.S. Cordillera. GSA Bulletin 2003;; 115 (9): 1122–1132. doi: https://doi.org/10.1130/B25219.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The western United States contains three thin but remarkably widespread alluvial conglomeratic units that record episodes of large-scale tilting across the U.S. Cordilleran orogen in post-Paleozoic time. These units are: (1) the Shinarump Conglomerate of Late Triassic age exposed in northern Arizona and adjacent parts of Utah, Nevada, and New Mexico; (2) Lower Cretaceous gravel deposits that overlie the Morrison Formation throughout the Rocky Mountain region; and (3) the gravel-rich parts of the Miocene-Pliocene age Ogallala Group in western Nebraska and adjacent southeastern Wyoming. Paleoslopes of the rivers depositing these units were in the range of 10−4 to 10−3, based on paleohydraulic calculations. However, depositional thickness trends of these units are not sufficient to have generated such steep paleoslopes. Thus, long wavelength tilting of the Earth's surface must have occurred for these gravels to be transported. Although these units were deposited adjacent to large tectonic features, including an evolving and migrating continental arc, and, for the Ogallala Group, the northward-propagating Rio Grande Rift, the tilting occurred over wavelengths too broad to be directly generated by these features. These widespread gravel units attest to the interplay between the creation of subduction-related isostatic and dynamic topography and continental sedimentation. Hence, paleotopography, as determined from calculated transport gradients of sedimentary deposits, provides a means of relating constructional landforms to mantle-driven processes. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.