Download or read book Advanced Geophysical Studies of Accretion of Oceanic Lithosphere in Mid ocean Ridges Characterized by Contrasting Tectono magmatic Settings written by Min Xu and published by . This book was released on 2012 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of the oceanic lithosphere results from magmatic and extensional processes taking place at mid-ocean ridges (MORs). The temporal and spatial scales of the variability of these two processes control the degree of heterogeneity of the oceanic lithosphere, represented by two end-member models: the classical Penrose Model exemplified by layered magmatic crust formed along fast-spreading MORs, e.g., East Pacific Rise (EPR); and the recently defined Chapman Model describing heterogeneous mafic and ultramafic lithosphere formed in settings of oceanic detachment faulting common along slow-spreading MORs, e.g., Mid-Atlantic Ridge (MAR). This thesis is using advanced marine geophysical methods (including finite-difference wave propagation modeling, 3D multi-channel seismic reflection imaging, waveform inversion, streamer tomography, and near-bottom magnetics) to study lithospheric accretion processes in MORs characterized by contrasting tectono-magmatic settings: the magmatically dominated EPR axis between 9°30'-10°00'N, and the Kane Oceanic Core Complex (KOCC), a section of MAR lithosphere (23°20'-23°38'N) formed by detachment faulting. At the EPR study area, I found that the axial magma chamber (AMC) melt sill is segmented into four prominent 2-4-km-long sections spaced every ~5- 10 km along the ridge axis characterized by high melt content (>95%). In contrast, within the intervening sections, the AMC sill has a lower melt content (41-46%). The total magma volume extracted from the AMC sill was estimated of ~46 × 106 m3, with ~24 × 106 m3 left unerupted in the upper crust as dikes after 2005-06 eruption. At the KOCC, I used streamer tomography to constrain the shallow seismic velocity structure. Lithological interpretation of the seismic tomographic models provides insights into the temporal and spatial evolution of the melt supply at the spreading axis as the KOCC formed and evolved. Investigation of a magnetic polarity reversal boundary in crosssection at the northern boundary of KOCC suggests that the boundary (representing both a frozen isotherm and an isochron) dips away from the ridge axis along the Kane transform fault scarp, with a west-dipping angle of ~45° in the shallow (
Download or read book Advanced Geophysical Studies of Accretion of Oceanic Lithosphere in Mid Ocean Ridges Characterized by Contrasting Tectono magmatic Settings written by Min Xu (Ph.D.) and published by . This book was released on 2012 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of the oceanic lithosphere results from magmatic and extensional processes taking place at mid-ocean ridges (MORs). The temporal and spatial scales of the variability of these two processes control the degree of heterogeneity of the oceanic lithosphere, represented by two end-member models: the classical Penrose Model exemplified by layered magmatic crust formed along fast-spreading MORs, e.g., East Pacific Rise (EPR); and the recently defined Chapman Model describing heterogeneous mafic and ultramafic lithosphere formed in settings of oceanic detachment faulting common along slow-spreading MORs, e.g., Mid-Atlantic Ridge (MAR). This thesis is using advanced marine geophysical methods (including finite-difference wave propagation modeling, 3D multi-channel seismic reflection imaging, waveform inversion, streamer tomography, and near-bottom magnetics) to study lithospheric accretion processes in MORs characterized by contrasting tectono-magmatic settings: the magmatically dominated EPR axis between 9°30'-10°00°N, and the Kane Oceanic Core Complex (KOCC), a section of MAR lithosphere (23°20°-23°38°N) formed by detachment faulting. At the EPR study area, I found that the axial magma chamber (AMC) melt sill is segmented into four prominent 2-4-km-long sections spaced every -5- 10 km along the ridge axis characterized by high melt content (>95%). In contrast, within the intervening sections, the AMC sill has a lower melt content (41-46%). The total magma volume extracted from the AMC sill was estimated of ~46 x 106 M3, with ~24 x 106 M3 left unerupted in the upper crust as dikes after 2005-06 eruption. At the KOCC, I used streamer tomography to constrain the shallow seismic velocity structure. Lithological interpretation of the seismic tomographic models provides insights into the temporal and spatial evolution of the melt supply at the spreading axis as the KOCC formed and evolved. Investigation of a magnetic polarity reversal boundary in crosssection at the northern boundary of KOCC suggests that the boundary (representing both a frozen isotherm and an isochron) dips away from the ridge axis along the Kane transform fault scarp, with a west-dipping angle of ~45° in the shallow (
Download or read book Directory of Geoscience Departments 2015 written by Carolyn Wilson and published by American Geosciences Inst. This book was released on 2015-02-27 with total page 2140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Directory of Geoscience Departments 50th Edition is the most comprehensive directory and source of information about geosciences departments and researchers available. It is an invaluable resource for individuals working in the geosciences or must identify or work with specialists on the issues of Earth, Environmental, and related sciences and engineering fields. The Directory of Geoscience Departments 50th Edition provides a state/country-sorted listing of nearly 2300 geoscience departments, research departments, institutes, and their faculty and staff. Information on contact information for departments and individuals is provided, as well as details on department enrollments, faculty specialties, and the date and source of faculty and staff's highest degree. New in the 50th edition: Listing of all US and Canadian geoscience theses and dissertations accepted in 2012 that have been reported to GeoRef Information Services, as well as a listing of faculty by their research specialty.
Download or read book Processes of Magmatic and Tectonic Accretion of Oceanic Lithosphere at Mid ocean Ridges written by Anke Dannowski and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Oceanic Crust from Accretion to Mantle Recycling written by Thierry Juteau and published by Springer. This book was released on 1999-04-15 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals mainly with the petrography and mineralogy of the rocks of the oceanic crust, and with petrological and geochemical processes. Structural processes are described in as far as they help in the understanding of the general processes controlling the formation and evolution of the oceanic crust and lithosphere. The book includes numerous examples and case studies, and is written in a clear and readable style which will make it popular with students.
Download or read book Mid Ocean Ridges written by Johnson Robin Cann and published by Cambridge University Press. This book was released on 1999-07-22 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers the most important problems that arise at mid-ocean ridges; for researchers working in the earth sciences.
Download or read book The Oceanic Lithosphere written by Cesare Emiliani and published by Harvard University Press. This book was released on 2005-06 with total page 1758 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crust Mantle and Lithosphere Asthenosphere Boundaries written by Gianluca Bianchini and published by Geological Society of America. This book was released on 2017-05-10 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 10-chapter volume encompasses contributions from a wide spectrum of Earth science disciplines, including geophysics, geodynamics, geochemistry, and petrology, to provide an overview of the nature and evolution of the crust-mantle and lithosphere-asthenosphere boundaries in different tectonic settings, combining studies that exploit different types of data and interpretative approaches. The integration of geochemical, geophysical, and geodynamic data sets and their interpretation provides a state-of-the-art summary of current understanding, and will serve as a blueprint for future research activities.
Download or read book Mid Ocean Ridges written by Roger Searle and published by Cambridge University Press. This book was released on 2013-09-19 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ideal multidisciplinary introduction to the key global phenomenon of mid-ocean ridges, for graduate and advanced undergraduate students and professionals.
Download or read book Evolution of Mid Ocean Ridges written by John M. Sinton and published by American Geophysical Union. This book was released on 1989 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: Outgrowth of IUGG Union Symposium 9 held during the 1987 IUGG General Assembly at Vancouver, Canada, and jointly sponsored by IAVCEI and others.
Download or read book RIDGE Events written by and published by . This book was released on 1990 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Margins written by National Research Council and published by National Academies Press. This book was released on 1990-02-01 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approximately 70 percent of the world's population is concentrated in the coastal borderlands, which geologists recognize to be the present continental margins. This new book on these continental margins provides a detailed account of a meeting which brought together specialists in marine and terrestrial geology, geochemistry, and geophysics. The workshop garnered widespread support and enthusiasm for a new direction in margins research focused on interdisciplinary studies of the fundamental processes of continental margin evolution. Scientific problems and solutions were identified for both divergent and convergent margins. Results of the workshop show that many of the fundamental plate interaction processes are common to all margins, whether formed by extension, contraction, or translation. This conclusion suggests a unified approach to margins research. A margins initiative has been proposed to follow up on the workshop results by developing science programs aimed at understanding the processes that control the initiation and evolution of continental margins.
Download or read book Duration Rates and Patterns of Crustal Growth at Slow spreading Mid ocean Ridges written by Craig B. Grimes and published by ProQuest. This book was released on 2008 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation addresses temporal and spatial characteristics of magmatic and tectonic accretion processes occurring at mid-ocean ridges during formation of new ocean lithosphere. The accretion histories of plutonic crust recovered by deep drilling of footwalls to large-displacement normal faults at three locations on the MAR are emphasized. Pb/U zircon dating of evolved gabbros and oceanic plagiogranites show that magmatic accretion typically occurs over 100-200 kyr. Magmatic accretion occurs by emplacement of many short-lived intrusive pulses that are focused at different depths within the crust and mantle. During formation of the Atlantis Massif core complex (30° N, MAR), spreading may have been partitioned up to 100% on the North American plate for at least 200 kyr, implying crustal accretion was highly asymmetric. Cooling rates of 1000-2000° C/m.y. over 900-200° C are documented at Atlantis Massif and two locations from 14-16°N, MAR, consistent with rapid denudation of the footwall sections to the seafloor following emplacement. Spreading rates combined with the time interval over which cooling to
Download or read book Processes of Magmatic and Tectonic Accretion of Oceanic Litosphere at Mid Ocean Ridges written by Anke Dannowski and published by . This book was released on 2009 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Insights Into Accretion and Cooling of Lower Ocean Crust at Ultraslow and Fast spreading Mid ocean Ridges written by Christopher James Doorn and published by . This book was released on 2022 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mid-ocean ridges are the primary divergent tectonic margins and generate the ocean crust, which covers ~60% of Earth’s surface. The gabbroic lower ocean crust hosts lithologic and structural diversity varying with spreading rate and magma supply. This dissertation examines lower crustal accretion at ultraslow- and fast-spreading ridges to better constrain crustal accretion and cooling across spreading rates. Trace element compositions of zircon from Atlantis Bank (Southwest Indian Ridge) characterize the final stages of magmatism and the thermal architecture in the lower crust produced along an ultraslow-spreading ridge. U-Pb zircon dates of evolved gabbroic rocks from the fast-spread lower crust at Pito Deep (East Pacific Rise) reveal significant off-axis magmatism, implying locally robust magmatism and relatively slow cooling of this nascent ocean crust. Textural characteristics of gabbroic rocks from Pito Deep highlight the lateral complexity of the fast-spread lower crust, and record increasing degrees of magmatic strain with depth. Synthesizing textural data, U-Pb geochronology, mineral chemistry, and magnetic data from Pito Deep supports a pulsed gabbro glacier flow process for generating the lower ocean crust at magmatically robust fast-spreading ridges.
Download or read book Ridge Segmentation Tectonic Evolution and Rheology of Slow spreading Oceanic Crust written by Javier Esteban Escartín Guiral and published by . This book was released on 1996 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Continental Crust written by Rolf Meissner and published by Academic Press. This book was released on 1986 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Suitable for advanced undergraduate and beginning graduate students in atmospheric, oceanic, and climate science, this textbook on the circulations of the atmosphere and ocean and their interaction emphasises on global scales. It gives students a grasp of what the atmosphere and oceans look like on the large-scale and why they look that way.
