Author: Genevive R. Mathers
Publisher:
ISBN: 9781109765090
Category : Climatic changes
Languages : en
Pages : 140
Book Description
There are a number of distinctive, penecontemporaneous, regionally distributed conglomeratic units in the central and southern U.S. Rocky Mountains whose origin and relationship to regional tectonics, climate change and basin evolution are unclear. These units - the Dark Canyon sequence of the Wasatch Formation in the Book Cliffs of Utah, the Ohio Creek Member of the Mesaverde Group in the Piceance Creek Basin of Colorado, the Arapahoe Conglomerate of the Denver Formation (D1 sequence) in the Denver Basin, the Canaan Peak Formation in the Kaiparowits Plateau of southwestern Utah, and the Ojo Alamo Formation in the San Juan Basin of Colorado and New Mexico - are generally thin and widespread, and abruptly prograde out across underlying units. They are broadly similar in composition, containing dominantly chert and quartzite clasts reworked from local Mesozoic and Paleozoic sources; they were deposited by gravelly river systems; they are unconformity-bounded; and they were all deposited at or around the Cretaceous/Paleogene boundary. While these units have been broadly dated using palynology, interpretation of their origins has been difficult given the scarcity of sample material and the large age ranges for some recovered palynomorphs. Young peak ages of U-Pb detrital zircon spectra, interpreted to represent a maximum depositional age, are used in conjunction with traditional basin analysis techniques and published age data to determine the depositional history of these conglomeratic units. Subsidence analysis indicates that the latest Cretaceous and early Paleogene were times of reduced subsidence rates in these basins, and that the conglomerates were deposited after the initiation of Laramide-related subsidence in these basins, or late-stage Sevier thrusting in the case of the Canaan Peak Formation. While reported ages of deposition of these units cover a large time span, it is permissible that deposition was synchronous between ~66 and ~64 Ma, given the overlap between published ages and U-Pb dates of detrital zircons. The overall similarities in depositional style and timing suggest that gravel dispersal at the Cretaceous/Paleogene boundary could have been a result of regional climate change. Published Global Climate Models and stable isotope studies suggest that the Rocky Mountain monsoon had begun on the eastern flanks of the Sevier belt by the Campanian and had moved east to the broken Laramide foreland by the Paleogene. The depositional model proposed by this study concludes that a period of tectonic quiescence in the rising Laramide uplifts, evidenced by a reduction in subsidence rates and basin-wide unconformities, in latest Cretaceous and early Paleogene time led to overall reduced subsidence rates that, when coupled with an abrupt increase in seasonal precipitation during the Rocky Mountain monsoon, promoted a basinward shift in facies and created erosional surfaces in the proximal parts of basins. Renewed tectonism and subsidence in late Paleocene through Eocene time caused a subsequent retraction of lithofacies, leading to onlap of coarse-grained material (the conglomerates in this study) onto these erosional surfaces and subsequent deposition of finer-grained deposits. Thus, tectonics coupled with climate change lead to the deposition of the widespread conglomerates found around the Cretaceous/Paleogene boundary in the central and southern Rocky Mountains.
Tectonic and Climatic Forcing of Widespread U.S. Rocky Mountain Conglomerates at the Cretaceous/Paleogene Boundary
Author: Genevive R. Mathers
Publisher:
ISBN: 9781109765090
Category : Climatic changes
Languages : en
Pages : 140
Book Description
There are a number of distinctive, penecontemporaneous, regionally distributed conglomeratic units in the central and southern U.S. Rocky Mountains whose origin and relationship to regional tectonics, climate change and basin evolution are unclear. These units - the Dark Canyon sequence of the Wasatch Formation in the Book Cliffs of Utah, the Ohio Creek Member of the Mesaverde Group in the Piceance Creek Basin of Colorado, the Arapahoe Conglomerate of the Denver Formation (D1 sequence) in the Denver Basin, the Canaan Peak Formation in the Kaiparowits Plateau of southwestern Utah, and the Ojo Alamo Formation in the San Juan Basin of Colorado and New Mexico - are generally thin and widespread, and abruptly prograde out across underlying units. They are broadly similar in composition, containing dominantly chert and quartzite clasts reworked from local Mesozoic and Paleozoic sources; they were deposited by gravelly river systems; they are unconformity-bounded; and they were all deposited at or around the Cretaceous/Paleogene boundary. While these units have been broadly dated using palynology, interpretation of their origins has been difficult given the scarcity of sample material and the large age ranges for some recovered palynomorphs. Young peak ages of U-Pb detrital zircon spectra, interpreted to represent a maximum depositional age, are used in conjunction with traditional basin analysis techniques and published age data to determine the depositional history of these conglomeratic units. Subsidence analysis indicates that the latest Cretaceous and early Paleogene were times of reduced subsidence rates in these basins, and that the conglomerates were deposited after the initiation of Laramide-related subsidence in these basins, or late-stage Sevier thrusting in the case of the Canaan Peak Formation. While reported ages of deposition of these units cover a large time span, it is permissible that deposition was synchronous between ~66 and ~64 Ma, given the overlap between published ages and U-Pb dates of detrital zircons. The overall similarities in depositional style and timing suggest that gravel dispersal at the Cretaceous/Paleogene boundary could have been a result of regional climate change. Published Global Climate Models and stable isotope studies suggest that the Rocky Mountain monsoon had begun on the eastern flanks of the Sevier belt by the Campanian and had moved east to the broken Laramide foreland by the Paleogene. The depositional model proposed by this study concludes that a period of tectonic quiescence in the rising Laramide uplifts, evidenced by a reduction in subsidence rates and basin-wide unconformities, in latest Cretaceous and early Paleogene time led to overall reduced subsidence rates that, when coupled with an abrupt increase in seasonal precipitation during the Rocky Mountain monsoon, promoted a basinward shift in facies and created erosional surfaces in the proximal parts of basins. Renewed tectonism and subsidence in late Paleocene through Eocene time caused a subsequent retraction of lithofacies, leading to onlap of coarse-grained material (the conglomerates in this study) onto these erosional surfaces and subsequent deposition of finer-grained deposits. Thus, tectonics coupled with climate change lead to the deposition of the widespread conglomerates found around the Cretaceous/Paleogene boundary in the central and southern Rocky Mountains.
Publisher:
ISBN: 9781109765090
Category : Climatic changes
Languages : en
Pages : 140
Book Description
There are a number of distinctive, penecontemporaneous, regionally distributed conglomeratic units in the central and southern U.S. Rocky Mountains whose origin and relationship to regional tectonics, climate change and basin evolution are unclear. These units - the Dark Canyon sequence of the Wasatch Formation in the Book Cliffs of Utah, the Ohio Creek Member of the Mesaverde Group in the Piceance Creek Basin of Colorado, the Arapahoe Conglomerate of the Denver Formation (D1 sequence) in the Denver Basin, the Canaan Peak Formation in the Kaiparowits Plateau of southwestern Utah, and the Ojo Alamo Formation in the San Juan Basin of Colorado and New Mexico - are generally thin and widespread, and abruptly prograde out across underlying units. They are broadly similar in composition, containing dominantly chert and quartzite clasts reworked from local Mesozoic and Paleozoic sources; they were deposited by gravelly river systems; they are unconformity-bounded; and they were all deposited at or around the Cretaceous/Paleogene boundary. While these units have been broadly dated using palynology, interpretation of their origins has been difficult given the scarcity of sample material and the large age ranges for some recovered palynomorphs. Young peak ages of U-Pb detrital zircon spectra, interpreted to represent a maximum depositional age, are used in conjunction with traditional basin analysis techniques and published age data to determine the depositional history of these conglomeratic units. Subsidence analysis indicates that the latest Cretaceous and early Paleogene were times of reduced subsidence rates in these basins, and that the conglomerates were deposited after the initiation of Laramide-related subsidence in these basins, or late-stage Sevier thrusting in the case of the Canaan Peak Formation. While reported ages of deposition of these units cover a large time span, it is permissible that deposition was synchronous between ~66 and ~64 Ma, given the overlap between published ages and U-Pb dates of detrital zircons. The overall similarities in depositional style and timing suggest that gravel dispersal at the Cretaceous/Paleogene boundary could have been a result of regional climate change. Published Global Climate Models and stable isotope studies suggest that the Rocky Mountain monsoon had begun on the eastern flanks of the Sevier belt by the Campanian and had moved east to the broken Laramide foreland by the Paleogene. The depositional model proposed by this study concludes that a period of tectonic quiescence in the rising Laramide uplifts, evidenced by a reduction in subsidence rates and basin-wide unconformities, in latest Cretaceous and early Paleogene time led to overall reduced subsidence rates that, when coupled with an abrupt increase in seasonal precipitation during the Rocky Mountain monsoon, promoted a basinward shift in facies and created erosional surfaces in the proximal parts of basins. Renewed tectonism and subsidence in late Paleocene through Eocene time caused a subsequent retraction of lithofacies, leading to onlap of coarse-grained material (the conglomerates in this study) onto these erosional surfaces and subsequent deposition of finer-grained deposits. Thus, tectonics coupled with climate change lead to the deposition of the widespread conglomerates found around the Cretaceous/Paleogene boundary in the central and southern Rocky Mountains.
Cenozoic History of the Southern Rocky Mountains
Author: Bruce Franklin Curtis
Publisher: Geological Society of America
ISBN: 0813711444
Category : Geology
Languages : en
Pages : 290
Book Description
Publisher: Geological Society of America
ISBN: 0813711444
Category : Geology
Languages : en
Pages : 290
Book Description
Cenozoic Systems of the Rocky Mountain Region
Author: SEPM (Society for Sedimentary Geology). Rocky Mountain Section
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 520
Book Description
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 520
Book Description
Cenozoic Paleogeography of the West-central United States
Author: Romeo M. Flores
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 476
Book Description
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 476
Book Description
Paleocene Flora of the Rocky Mountains and Great Plains
Author: Roland Wilbur Brown
Publisher:
ISBN:
Category : Paleobotany
Languages : en
Pages : 266
Book Description
A study of 170 kinds of plants and the strata that yield them, showing how they apply in the delimination of the Paleocene series.
Publisher:
ISBN:
Category : Paleobotany
Languages : en
Pages : 266
Book Description
A study of 170 kinds of plants and the strata that yield them, showing how they apply in the delimination of the Paleocene series.
Cenozoic History of the Southern Rocky Mountains
Author: Bruce Franklin Curtis
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 279
Book Description
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 279
Book Description
The Sedimentary Basins of the United States and Canada
Author: Andrew Miall
Publisher: Elsevier
ISBN: 0444638962
Category : Science
Languages : en
Pages : 826
Book Description
The Sedimentary Basins of the United States and Canada, Second Edition, focuses on the large, regional, sedimentary accumulations in Canada and the United States. Each chapter provides a succinct summary of the tectonic setting and structural and paleogeographic evolution of the basin it covers, with details on structure and stratigraphy. The book features four new chapters that cover the sedimentary basins of Alaska and the Canadian Arctic. In addition to sedimentary geologists, this updated reference is relevant for basin analysis, regional geology, stratigraphy, and for those working in the hydrocarbon exploration industry. - Features updates to existing chapters, along with new chapters on sedimentary basins in Alaska and Arctic Canada - Includes nearly 300 detailed, full-color paleogeographic maps - Written for general geological audiences and individuals working in the resources sector, particularly those in the fossil fuel industry
Publisher: Elsevier
ISBN: 0444638962
Category : Science
Languages : en
Pages : 826
Book Description
The Sedimentary Basins of the United States and Canada, Second Edition, focuses on the large, regional, sedimentary accumulations in Canada and the United States. Each chapter provides a succinct summary of the tectonic setting and structural and paleogeographic evolution of the basin it covers, with details on structure and stratigraphy. The book features four new chapters that cover the sedimentary basins of Alaska and the Canadian Arctic. In addition to sedimentary geologists, this updated reference is relevant for basin analysis, regional geology, stratigraphy, and for those working in the hydrocarbon exploration industry. - Features updates to existing chapters, along with new chapters on sedimentary basins in Alaska and Arctic Canada - Includes nearly 300 detailed, full-color paleogeographic maps - Written for general geological audiences and individuals working in the resources sector, particularly those in the fossil fuel industry
Geology of the American Southwest
Author: W. Scott Baldridge
Publisher: Cambridge University Press
ISBN: 9780521016667
Category : Science
Languages : en
Pages : 316
Book Description
This 2004 book provides a concise, accessible account of the geology and landscape of Southwest USA, for students and amateurs.
Publisher: Cambridge University Press
ISBN: 9780521016667
Category : Science
Languages : en
Pages : 316
Book Description
This 2004 book provides a concise, accessible account of the geology and landscape of Southwest USA, for students and amateurs.
Mountains, Glaciers, and Mines
Author: Karl S. Kellogg
Publisher:
ISBN:
Category : Blue River (Colo. : River)
Languages : en
Pages : 44
Book Description
Publisher:
ISBN:
Category : Blue River (Colo. : River)
Languages : en
Pages : 44
Book Description
The Gulf of Mexico Sedimentary Basin
Author: John W. Snedden
Publisher: Cambridge University Press
ISBN: 110841902X
Category : Business & Economics
Languages : en
Pages : 343
Book Description
A comprehensive and richly illustrated overview of the Gulf of Mexico Basin, including its reservoirs, source rocks, tectonics and evolution.
Publisher: Cambridge University Press
ISBN: 110841902X
Category : Business & Economics
Languages : en
Pages : 343
Book Description
A comprehensive and richly illustrated overview of the Gulf of Mexico Basin, including its reservoirs, source rocks, tectonics and evolution.