Colorado River Origin and Evolution

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