Crustal Magmatism and Lithospheric Geothermal State of Western North America and Their Implications for a Magnetic Mantle

Crustal Magmatism and Lithospheric Geothermal State of Western North America and Their Implications for a Magnetic Mantle PDF Author: Jian Wang
Publisher:
ISBN:
Category : Magmatism
Languages : en
Pages : 14

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Book Description
The western North American lithosphere experienced extensive magmatism and large-scale crustal deformation due to the interactions between the Farallon and North American plates. To further understand such subduction-related dynamic processes, we characterize crustal structure, magmatism and lithospheric thermal state of western North America based on various data processing and interpretation of gravimetric, magnetic and surface heat flow data. A fractal exponent of 2.5 for the 3D magnetization model is used in the Curie-point depth inversion. Curie depths are mostly small to the north of the Yellowstone-Snake River Plain hotspot track, including the Steens Mountain and McDermitt caldera that are the incipient eruption locations of the Columbia River Basalts and Yellowstone hotspot track. To the south of the Yellowstone hotspot track, larger Curie depths are found in the Great Basin. The distinct Curie depths across the Yellowstone-Snake River Plain hotspot track can be attributed to subduction-related magmatism induced by edge flow around fractured slabs. Curie depths confirm that the Great Valley ophiolite is underlain by the Sierra Nevada batholith, which can extend further west to the California Coast Range. The Curie depths, thermal lithospheric thickness and surface heat flow together define the western edge of the North American craton near the Roberts Mountains Thrust (RMT). To the east of the RMT, large Curie depths, large thermal lithospheric thickness, and low thermal gradient are found. From the differences between Curie-point and Moho depth, we argue that the uppermost mantle in the oceanic region is serpentinized. The low temperature gradients beneath the eastern Great Basin, Montana and Wyoming permit magnetic uppermost mantle, either by serpentinization/metasomatism or in-situ magnetization, which can contribute to long-wavelength and low-amplitude magnetic anomalies and thereby large Curie-point depths.

Crustal Magmatism and Lithospheric Geothermal State of Western North America and Their Implications for a Magnetic Mantle

Crustal Magmatism and Lithospheric Geothermal State of Western North America and Their Implications for a Magnetic Mantle PDF Author: Jian Wang
Publisher:
ISBN:
Category : Magmatism
Languages : en
Pages : 14

Get Book Here

Book Description
The western North American lithosphere experienced extensive magmatism and large-scale crustal deformation due to the interactions between the Farallon and North American plates. To further understand such subduction-related dynamic processes, we characterize crustal structure, magmatism and lithospheric thermal state of western North America based on various data processing and interpretation of gravimetric, magnetic and surface heat flow data. A fractal exponent of 2.5 for the 3D magnetization model is used in the Curie-point depth inversion. Curie depths are mostly small to the north of the Yellowstone-Snake River Plain hotspot track, including the Steens Mountain and McDermitt caldera that are the incipient eruption locations of the Columbia River Basalts and Yellowstone hotspot track. To the south of the Yellowstone hotspot track, larger Curie depths are found in the Great Basin. The distinct Curie depths across the Yellowstone-Snake River Plain hotspot track can be attributed to subduction-related magmatism induced by edge flow around fractured slabs. Curie depths confirm that the Great Valley ophiolite is underlain by the Sierra Nevada batholith, which can extend further west to the California Coast Range. The Curie depths, thermal lithospheric thickness and surface heat flow together define the western edge of the North American craton near the Roberts Mountains Thrust (RMT). To the east of the RMT, large Curie depths, large thermal lithospheric thickness, and low thermal gradient are found. From the differences between Curie-point and Moho depth, we argue that the uppermost mantle in the oceanic region is serpentinized. The low temperature gradients beneath the eastern Great Basin, Montana and Wyoming permit magnetic uppermost mantle, either by serpentinization/metasomatism or in-situ magnetization, which can contribute to long-wavelength and low-amplitude magnetic anomalies and thereby large Curie-point depths.

Continental Basin and Orogenic Processes: Deep Structure, Tectonic Deformation, and Dynamics

Continental Basin and Orogenic Processes: Deep Structure, Tectonic Deformation, and Dynamics PDF Author: Hanlin Chen
Publisher: Frontiers Media SA
ISBN: 2832503969
Category : Science
Languages : en
Pages : 392

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Book Description


U.S. Geological Survey Professional Paper

U.S. Geological Survey Professional Paper PDF Author:
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 472

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Mantle to Magma

Mantle to Magma PDF Author: B. R. Edwards
Publisher:
ISBN:
Category :
Languages : en
Pages : 154

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Book Description


Treatise on Geophysics, Volume 6

Treatise on Geophysics, Volume 6 PDF Author: Anthony B Watts
Publisher: Elsevier
ISBN: 0444535721
Category : Science
Languages : en
Pages : 627

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Book Description
Treatise on Geophysics: Crust and Lithosphere Dynamics, Volume 6, provides a comprehensive review of the state of knowledge on crust and lithosphere dynamics, which is defined as the study of how the outermost layers of the Earth respond to loads that are emplaced on, within, and below it and its implications for plate mechanics and mantle flow. The book begins with a chapter on plate kinematics, which shows how new observations and methodologies have improved the resolution of relative and absolute plate motions. This is followed by studies of plate mechanics, focusing on the long-term rheology of the plates and response of the plates to both relatively short-term and long-term loads. The book also includes chapters that examine the evidence from surface heat flow, borehole breakouts, and magma models for the thermal and mechanical structure of the lithosphere; the deformation of the lithosphere in extensional and compressional settings. The final two chapters deal with the structural styles of faulting in the shallow brittle part of the lithosphere, the brittle-ductile transition, and the shear zone in the ductile part of the lithosphere; and how developments in plate mechanics have impacted our understanding of geological processes. Self-contained volume starts with an overview of the subject then explores each topic with in depth detail Extensive reference lists and cross references with other volumes to facilitate further research Full-color figures and tables support the text and aid in understanding Content suited for both the expert and non-expert

Quaternary Magmatism in the Cascades

Quaternary Magmatism in the Cascades PDF Author: Wes Hildreth
Publisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 140

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Treatise on Geophysics

Treatise on Geophysics PDF Author:
Publisher: Elsevier
ISBN: 0444538038
Category : Science
Languages : en
Pages : 5604

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Book Description
Treatise on Geophysics, Second Edition, is a comprehensive and in-depth study of the physics of the Earth beyond what any geophysics text has provided previously. Thoroughly revised and updated, it provides fundamental and state-of-the-art discussion of all aspects of geophysics. A highlight of the second edition is a new volume on Near Surface Geophysics that discusses the role of geophysics in the exploitation and conservation of natural resources and the assessment of degradation of natural systems by pollution. Additional features include new material in the Planets and Moon, Mantle Dynamics, Core Dynamics, Crustal and Lithosphere Dynamics, Evolution of the Earth, and Geodesy volumes. New material is also presented on the uses of Earth gravity measurements. This title is essential for professionals, researchers, professors, and advanced undergraduate and graduate students in the fields of Geophysics and Earth system science. Comprehensive and detailed coverage of all aspects of geophysics Fundamental and state-of-the-art discussions of all research topics Integration of topics into a coherent whole

Geoinformatics

Geoinformatics PDF Author: A. Krishna Sinha
Publisher: Geological Society of America
ISBN: 0813723973
Category : Science
Languages : en
Pages : 292

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Book Description
"The science of informatics in the broadest sense has been several thousands of years in the making. With the recent emergence of large storage devices and high-speed processing of data, it has become possible to organize vast amounts of data as digital products with ontologic tags and concepts for smart queries. Coupling this computational capability with earth science data defines the emerging field of geoinformatics. Since the science of geology was established several centuries ago, observations led to conclusions that were integrative in concept and clearly had profound implications for the birth of geology. As disciplinary information about Earth becomes more voluminous, the use of geoinformatics will lead to integrative, science-based discoveries of new knowledge about planetary systems. Twenty one research papers, co-authored by 96 researchers from both earth and computer sciences, provide the first-ever organized presentation of the science of informatics as it relates to geology. Readers will readily recognize the vast intellectual content represented by these papers as they seek to address the core research goals of geoinformatics."--Publisher's website.

Publications of the Geological Survey

Publications of the Geological Survey PDF Author: Geological Survey (U.S.)
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 456

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Book Description


The Tectonic Setting and Origin of Cretaceous Batholiths within the North American Cordillera

The Tectonic Setting and Origin of Cretaceous Batholiths within the North American Cordillera PDF Author: Robert S. Hildebrand
Publisher: Geological Society of America
ISBN: 0813725321
Category : Nature
Languages : en
Pages : 123

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Book Description
In this Special Paper, Hildebrand and Whalen present a big-picture, paradigm-busting synthesis that examines the tectonic setting, temporal relations, and geochemistry of many plutons within Cretaceous batholithic terranes of the North American Cordillera. In addition to their compelling tectonic synthesis, they argue that most of the batholiths are not products of arc magmatism as commonly believed, but instead were formed by slab failure during and after collision. They show that slab window and Precambrian TTG suites share many geochemical similarities with Cretaceous slab failure rocks. Geochemical and isotopic data indicate that the slab failure magmas were derived dominantly from the mantle and thus have been one of the largest contributors to growth of continental crust. The authors also note that slab failure plutons emplaced into the epizone are commonly associated with Cu-Au porphyries, as well as Li-Cs-Ta pegmatites.