Colorado River: Origin and Evolution; Proceedings of a Symposium Held at Grand Canyon National Park in June, 2000 (Monograph)

Cover......Page 1 Colorado River: Origin and Evolution......Page 3 ©......Page 4 DEDICATION......Page 5 CONTENTS......Page 6 Introduction......Page 10 Section A: Early Tertiary Events and Regional Geologic Setting......Page 13 The Laramide-Paleogene History of the Western Grand Canyon Region: Setting the Stage......Page 14 Paleogeomorphic Evolution of the Salt River Region: Implications for Cretaceous-Laramide Inheritance for Ancestral Colorado River Drainage......Page 24 Paleocene to Early Oligocene Basin Evolution, Southwestern Utah......Page 31 Fission-track Analysis of Apatite and Zircon from Grand Canyon, Arizona......Page 37 Laramide Cooling Histories of Grand Canyon, Arizona, and the Front Range, Colorado, Determined from Apatite Fission-track Thermochronology......Page 43 Section B: Areal Geologic Studies......Page 50 Age and Depositional Basin Morphology of the Bidahochi Formation and Imphcations for the Ancestral Upper Colorado River......Page 51 K-Ar Geochronologic Survey of the Hopi Buttes Volcanic Field......Page 56 Pliocene-Pleistocene Incision on the MogoUon Slope, Northern Arizona: Response to the Developing Grand Canyon......Page 61 Geomorphic Features and Processes of the Shivwits Plateau, Arizona, and Their Constraints on the Age of Western Grand Canyon......Page 67 Post-6 Ma Limestone Along the Southeastern Part of the Las Vegas Valley Shear Zone, Southern Nevada......Page 79 Depositional Environment and Paleogeographic Implications of the Late Miocene Hualapai Limestone, Northwestern Arizona and Southern Nevada......Page 83 40Ar/39Ar Geochronology of the Hualapai Limestone and Bouse Formation and Implications for the Age of the Lower Colorado River......Page 91 Pre-Colorado River Paleogeography and Extension Along the Colorado Plateau-Basin and Range Boundary, Northwestern Arizona......Page 95 Lower Colorado River :Upper Cenozoic Deposits, Incision, and Evolution......Page 103 Proposed Lower Colorado River Courses Prior to 4.3 Ma, Sonora, Mexico......Page 109 Section C: Estimating Rates of Incision......Page 112 Constraints on Timing and Rates of Late Cenozoic Incision by the Colorado River in Glenwood Canyon, Colorado: A Preliminary Synopsis......Page 113 Quaternary Incision Rates of the Colorado River and Major Tributaries in the Colorado Plateau, Utah......Page 118 Bedrock Incision Rates for the Fremont River, Tributary of the Colorado River......Page 124 The Colorado River and the Age of Glen Canyon......Page 128 Erosional History of the Colorado River through Glen and Grand Canyons......Page 134 Preliminary Evidence from Grand Canyon Caves and Mines for the Evolution of Grand Canyon and the Colorado River System......Page 140 Cosmogenic 3He Dating of Western Grand Canyon Basalts: Implications for Quaternary Incision of the Colorado River......Page 146 Rates of Downcutting of the Colorado River in the Grand Canyon Region......Page 153 Relating Differential Incision of Grand Canyon to Slip along the Hurricane/Toroweap Fault System......Page 157 Section D: Geochemistry and Uplift......Page 163 Application of Sr Isotopes to the Hydrology of the Colorado River System Waters and Potentially Related Neogene Sedimentary Formations......Page 164 The Bouse Formation and Post-Miocene Uplift of the Colorado Plateau......Page 170 Section E: Geologic Processes......Page 177 Debris Flows and Rapids in Grand Canyon: Implications for Erosion Rates and Evacuation of Sediment from Tributary Canyons......Page 178 Climate Change and the Evolution of Grand Canyon and the Colorado River Delta......Page 185 Section F: Selected Theories and Speculation......Page 190 Lake Overflow: An Alternative Hypothesis for Grand Canyon Incision and Development of the Colorado River......Page 191 Neogene Development of Little Colorado River Valley and Eastern Grand Canyon: Field Evidence for an Overtopping Hypothesis......Page 198 Headward Erosion Versus Closed-basin Spillover as Alternative Causes of Neogene Capture of the Ancestral Colorado River by the Gulf of Cahfornia......Page 205 Section G: Important Extrusive and Intrusive Igneous Rock Units......Page 211 Volcanic Rocks of the Grand Canyon Area......Page 212 Appendices......Page 220 A: Geochron Database......Page 221 B: Authors and Contact Information......Page 238 C: Roster of Symposium Attendees......Page 240 Index......Page 262 References Cited......Page 242