Download or read book New Insights Into Mantle Dynamics from Helium Isotopes and Argon Geochronology written by Kevin Konrad and published by . This book was released on 2017 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earth’s mantle extends to nearly 3000 km depth, comprises >80 % of Earth’s total volume, and has the largest influence on the primordial and radiogenic heat budget. Despite its importance, the structure and composition of the mantle is still debated. There are three primary models for Earth’s mantle structure that contain some degree of overlap. First, the Burke model invokes both small scale convection in the upper mantle coupled with larger scale, whole mantle convection. This model implies that long lived intraplate volcanic island chains are derived from upwelling plumes that originate near the edges of thermochemical piles in the lower mantle, while smaller and more ephemeral volcanic provinces originate from melting in the upper mantle. Second, the Courtillot model is similar to the Burke model, except multiple plume types exist, some originating from the core-mantle boundary and some separating from massive lower mantle upwellings that stall near the mantle transition zone at 400-660 km. Third, the Anderson model invokes upper and lower mantle isolation throughout Earth’s history, with volcanism originating through melting of a chemically heterogeneous upper mantle. The origin and evolution of intraplate volcanism are therefore central to understanding the dynamics and evolution of the mantle. In this dissertation, I present new constraints on Earth’s mantle using geochemical, geochronological and geodynamical investigations of intraplate volcanism in both continental and oceanic settings. The first study focuses on the origin of the enigmatic intraplate volcanic fields (harrats) of Saudi Arabia. Helium isotope compositions and trace element concentrations were determined for mantle xenoliths and lava flows from Harrat Hutaymah, plus 3He/4He in several xenoliths from Harrat Al Birk, Al Kishb, and Ithnayn. Harrat Hutaymah is the most northeastern Arabian volcanic field, found off of the main axis of Arabian volcanism, referred to as the Makkah-Medinah-Nafud (MMN) line. Hutaymah has uniform 3He/4He of 7.5 R[subscript A] (where R[subscript A] is the atmospheric ratio) in nearly all xenolith types. The uniformity is explained by volatile equilibration between the xenoliths and the host magma through the trapping of fluids/gases along grain defects during magma ascent, followed by re-annealing at lower pressure. Anhydrous spinel lherzolites from Hutaymah, Ithnanyn and Al Birk are notably different, having lower 3He/4He of 6.8 R[subscript A] and distinctly depleted light rare earth element signatures. The widespread presence of this 6.8 R[subscript A] signature in the lherzolites appears to be representative of the Arabian Proterozoic lithosphere prior to any metasomatic overprinting associated with later volcanic/tectonic activity. The origin of volcanism associated with the harrats located off the MMN line appears to involve mixing of delaminated, ancient enriched lithosphere with shallow depleted asthenosphere. Elevated 3He/4He signatures associated with a deep mantle plume origin are absent in the peripheral harrats, although they appear to be weakly present in some volcanic formations along the MMN line. The second study investigated intraplate volcanism in the Marquesas Islands, French Polynesia. This archipelago represents the surface expression of a low buoyancy flux mantle plume in a region of oceanic lithosphere marked by deep seated fracture zones. The Marquesas plume appears to contain an intrinsically large isotopic and chemical heterogeneity, both geographically and through time. The study uses 3He/4He results, major and trace element compositions of whole rocks, 40Ar/39Ar age determinations, and chemical analyses of olivine-hosted melt inclusions (OHMIs). The new results indicate that magmas feeding Marquesas volcanism are chemically diverse and are derived by melting of small-scale heterogeneities in the source regions. Variation in Cl/K among the OHMIs suggests that both the melting of recycled altered crust and interaction of magmas with brine at shallow levels potentially affects the lavas erupted in this region. Lavas at Hiva Oa show an increase in 3He/4He from shield (8.3 R[subscript A]; 2.6 Ma) to late-shield stage (10.4-14.5 R[subscript A]; 2.2 Ma), followed by a slight decrease (9.0-11.4 R[subscript A]) during the post-shield phase (1.8 Ma). Elevated 3He/4He ratios (10 R[subscript A]) are restricted to the central islands of Nuku Hiva and Hiva Oa in the Marquesas chain, suggesting a concentrically zoned mantle plume that has primitive and hot material concentrated near its central axis. The third study provides a refined history of the Rurutu hotspot, a long-lived mantle plume situated beneath the Pacific plate. Provided are new 40Ar/39Ar age determinations for seamounts from the Tuvalu Islands region of the west Pacific. These islands and seamounts range in age from 64 to 47 Ma and are isotopically similar to some young volcanoes in the Cook-Austral region. Using age constrained seamounts from the Rurutu chain (0-10 Ma; 47-72 Ma) in combination with the Pacific Louisville hotspot (0-79 Ma) and Hawaiian hotspot (0-78 Ma), the relative motions of these hotspots were computed. These motions confirm that Hawaii is unique, having an abrupt, southward plume drift from 60-47 Ma, while both Louisville and Rurutu show similar, eastward trending motions. Using geodynamic models of plume motions based primarily on seismic tomography and mantle viscosity models, the conditions required to account for the observed motions were tested. The relative motions are best reproduced when the plumes are both rooted near the core-mantle boundary and have roots that are able to move by mantle flow. However, none of the model parameters can properly reproduce the rapid motions of the Hawaiian hotspot, indicating additional processes may be responsible. The relative hotspot motions cannot be reproduced when the plumes are sourced at the upper/lower mantle boundary and thus indicate a deeper origin for long-lived plumes. The studies presented herein generally support the Burke model for mantle structure. The results from age-progressive Pacific intraplate volcanism support a plume source that is derived from dense thermochemical piles in the lower mantle. These source regions have somewhat mobile edges and contain a component of primitive material. Geochemical results for the Arabian volcanic fields indicate that secondary convection in the upper mantle may generate melts near the lithosphere-asthenosphere boundary, and therefore also be a cause of intraplate volcanism.

Download or read book U S Geological Survey Professional Paper written by and published by . This book was released on 1987 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Core Mantle Co Evolution written by Takashi Nakagawa and published by John Wiley & Sons. This book was released on 2023-05-23 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: New insights into interactions between the core and mantle. The Earth’s deep interior is difficult to study directly but recent technological advances have enabled new observations, experiments, analysis, and simulations to better understand deep Earth processes. Core-Mantle Co-Evolution: An Interdisciplinary Approach seeks to address some of the major unsolved issues around the core-mantle interaction and co-evolution. It provides the latest insights into dynamics, structure, and evolution in the core-mantle boundary region. Volume highlights include: Latest technological advances in high pressure experiments and their application to understanding the mineral physical properties and stability of phases in deep Earth Recent progress in observational seismology, geochemical analysis, geoneutrino experiments, and numerical modeling for understanding the heterogeneity of the lower mantle Theoretical investigations on thermal-chemical evolution of Earth’s mantle and core Exploring thermal-chemical-mechanical-electromagnetic interactions in the core-mantle boundary regions The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Download or read book Noble Gases written by Donald P. Porcelli and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 47 of Reviews in Mineralogy and Geochemistry introduces to Noble Gases. Although the mass spectrometry principles are not complex, the tricks involved in getting better data are often self taught or passed on by working with individuals who themselves are pushing the boundaries further. Furthermore, much of the exciting new science is linked with technical developments that allow us to move beyond the current measurement capabilities. Be they better crushing devices, laser resonance time of flight, multiple collection or compressor sources - the technical issues are central to progress. Contents: Noble Gases – Noble Science An Overview of Noble Gas Geochemistry and Cosmochemistry Noble Gases in the Solar System Noble Gases in the Moon and Meteorites: Radiogenic Components and Early Volatile Chronologies Cosmic-Ray-Produced Noble Gases in Meteorites Martian Noble Gases Origin of Noble Gases in the Terrestrial Planets Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs Noble Gases and Volatile Recycling at Subduction Zones The Storage and Transport of Noble Gases in the Subcontinental Lithosphere Models for the Distribution of Terrestrial Noble Gases and the Evolution of the Atmosphere Production, Release and Transport of Noble Gases in the Continental Crust Tracing Fluid Origin, Transport and Interaction in the Crust Noble Gases in Lakes and Ground Waters Noble Gases in Ocean Waters and Sediments Cosmic-Ray-Produced Noble Gases in Terrestrial Rocks: Dating Tools for Surface Processes K-Ar and Ar-Ar Dating (U-Th)/He Dating: Techniques, Calibrations, and Applications

Download or read book Recent Advances in Volcanic Gas Science written by Andrew McGonigle and published by Frontiers Media SA. This book was released on 2020-01-23 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volcanoes release gases to the atmosphere both during and between eruptive phases. Primary and secondary processes occurring within the mantle and crust control the gases’ chemical and isotopic compositions as well as their emission rates. Therefore by measuring these gases a wealth of scientific information concerning the source and fate of these fluids is provided. Fluid geochemistry has been highly useful in advancing both our fundamental scientific understanding and procedures for operational volcano monitoring and eruption forecasting. Gases from low-to-high temperature fumaroles and those diffusively released through the soils of volcanic flanks are investigated using various sampling and measurement techniques. Furthermore, a variety of remote sensing methods are applied at relatively great distances from the source to gather major gas composition and flux data for volcanic plumes using ground based, airborne (including UAV) and space borne platforms. The acquired data have advanced science in a number of key ways: • firstly, with parallel thermodynamical modelling to advance our capacity to interpret acquired degassing data; • secondly, through improved constraints on budgets for volcanically mediated geochemical cycling, particularly via regional subduction processes; • thirdly, through improved constraints on the effects of volcanic gases on atmospheric composition, chemistry and radiative transfer, particularly in terms of halogen chemistry, volcanogenic climate change and impacts on human health; • fourthly, there has been a growing body of work focused on combining degassing data with contemporaneous geophysical data and studies on conduit fluid dynamics to advance our understanding of how subterranean gas flow mediates activity at the surface; • and fifthly, there have been considerable advances in the methods themselves, used to make the gas measurements, in particular in terms of extractive sampling (e.g., using MultiGAS units, mass spectrometry, spectroscopic isotope measurement approaches and diffusive denuder sampling) and remote sensing approaches (e.g., DOAS, UV cameras and other imaging techniques, LIDAR and FT)

Download or read book Mantle Dynamics written by David Bercovici and published by Elsevier. This book was released on 2025-01-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mantle Dynamics provides an in-depth overview of the field of mantle dynamics in its present state. It surveys the physics and fluid dynamics of mantle convection, with theoretical, laboratory and computational methods. The volume also reviews the present understanding of convection in Earth's mantle, including energy sources and thermal evolution, upper-mantle flow, the fate of subducting slabs, hotspots and mantle plumes, and convective mixing and mantle geochemistry. Self-contained volume starts with an overview of the subject then explores each topic in 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

Download or read book Volcanism in Hawaii written by Geological Survey (U.S.) and published by . This book was released on 1987 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: v. 1. Physiography, tectonics, and submarine geology ; Geology of the island of Hawaii ; Petrogenesis and volcanic gases -- v. 2. Structure ; Dynamics ; History of investigations of Hawaiian volcanism.

Download or read book Geochemistry written by William M. White and published by John Wiley & Sons. This book was released on 2013-01-22 with total page 1218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to the field of geochemistry. The book first lays out the ‘geochemical toolbox’: the basic principles and techniques of modern geochemistry, beginning with a review of thermodynamics and kinetics as they apply to the Earth and its environs. These basic concepts are then applied to understanding processes in aqueous systems and the behavior of trace elements in magmatic systems. Subsequent chapters introduce radiogenic and stable isotope geochemistry and illustrate their application to such diverse topics as determining geologic time, ancient climates, and the diets of prehistoric peoples. The focus then broadens to the formation of the solar system, the Earth, and the elements themselves. Then the composition of the Earth itself becomes the topic, examining the composition of the core, the mantle, and the crust and exploring how this structure originated. A final chapter covers organic chemistry, including the origin of fossil fuels and the carbon cycle’s role in controlling Earth’s climate, both in the geologic past and the rapidly changing present. Geochemistry is essential reading for all earth science students, as well as for researchers and applied scientists who require an introduction to the essential theory of geochemistry, and a survey of its applications in the earth and environmental sciences. Additional resources can be found at: www.wiley.com/go/white/geochemistry

Download or read book Mantle Convection and Surface Expressions written by Hauke Marquardt and published by John Wiley & Sons. This book was released on 2021-07-07 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multidisciplinary perspective on the dynamic processes occurring in Earth's mantle The convective motion of material in Earth's mantle, powered by heat from the deep interior of our planet, drives plate tectonics at the surface, generating earthquakes and volcanic activity. It shapes our familiar surface landscapes, and also stabilizes the oceans and atmosphere on geologic timescales. Mantle Convection and Surface Expressions brings together perspectives from observational geophysics, numerical modelling, geochemistry, and mineral physics to build a holistic picture of the deep Earth. It explores the dynamic processes occurring in the mantle as well as the associated heat and material cycles. Volume highlights include: Perspectives from different scientific disciplines with an emphasis on exploring synergies Current state of the mantle, its physical properties, compositional structure, and dynamic evolution Transport of heat and material through the mantle as constrained by geophysical observations, geochemical data and geodynamic model predictions Surface expressions of mantle dynamics and its control on planetary evolution and habitability The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Download or read book Gas Geochemistry written by Claude Dubois and published by . This book was released on 1995 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Geochemical Data written by Hugh Rollinson and published by Cambridge University Press. This book was released on 2021-05-06 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook is a complete rewrite, and expansion of Hugh Rollinson's highly successful 1993 book Using Geochemical Data: Evaluation, Presentation, Interpretation. Rollinson and Pease's new book covers the explosion in geochemical thinking over the past three decades, as new instruments and techniques have come online. It provides a comprehensive overview of how modern geochemical data are used in the understanding of geological and petrological processes. It covers major element, trace element, and radiogenic and stable isotope geochemistry. It explains the potential of many geochemical techniques, provides examples of their application, and emphasizes how to interpret the resulting data. Additional topics covered include the critical statistical analysis of geochemical data, current geochemical techniques, effective display of geochemical data, and the application of data in problem solving and identifying petrogenetic processes within a geological context. It will be invaluable for all graduate students, researchers, and professionals using geochemical techniques.

Download or read book The Galapagos written by Karen S. Harpp and published by John Wiley & Sons. This book was released on 2014-07-22 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Galápagos Islands are renown for their unique flora and fauna, inspiring Charles Darwin in the elaboration of his theory of evolution. Yet in his Voyage of the Beagle, published in 1839, Darwin also remarked on the fascinating geology and volcanic origin of these enchanted Islands. Since then, the Galápagos continue to provide scientists with inspiration and invaluable information about ocean island formation and evolution, mantle plumes, and the deep Earth. Motivated by an interdisciplinary Chapman Conference held in the Islands, this AGU volume provides cross-disciplinary collection of recent research into the origin and nature of ocean islands, from their deepest roots in Earth's mantle, to volcanism, surface processes, and the interface between geology and biodiversity. Volume highlights include: Case studies in biogeographical, hydrological, and chronological perspective Understanding the connection between geological processes and biodiversity Synthesis of decades of interdisciplinary research in physical processes from surface to deep interior of the earth In-depth discussion of the concept of the island acting as a natural laboratory for earth scientists Integrated understanding of the Galápagos region from a geological perspective Collectively, The Galápagos presents case studies illustrating the Galápagos Archipelago as a dynamic natural laboratory for the earth sciences. This book would be of special interest to a multidisciplinary audience in earth sciences, including petrologists, volcanologists, geochronologists, geochemists, and geobiologists.

Download or read book Mantle Xenoliths written by Peter H. Nixon and published by John Wiley & Sons. This book was released on 1987 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: The eruption of deep-seated xenoliths in basaltic, alnoitic, kimberlitic, etc volcanoes provides the geologist with an important direct means of examining the fragments of the earth's mantle and lower crust.

Download or read book The Web of Geological Sciences written by Marion E. Bickford and published by Geological Society of America. This book was released on 2017-09-29 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The web of geological sciences, Special papers 500 and 523, written in celebration of the 125th anniversary of the Geological Society of America.

Download or read book Origin Evolution Environmental Impact of Oceanic LIPs written by Clive R. Neal and published by Geological Society of America. This book was released on 2015-05 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin, evolution, and environmental impact of large igneous provinces (LIPs) represents a topic of high scientific importance because the magmatism associated with these features cannot be directly related to plate tectonics, and because the eruption of flood basalts may have global environmental consequences. Oceanic LIPs are even more poorly understood due to their relative inaccessibility. This volume takes a multidisciplinary approach to understanding LIP origin, evolution, and environmental impact in ocean basins. Papers that focus on plate tectonic reconstructions, petrologic and geophysical investigations of various LIPs, and sedimentological and micropaleontological evidence of syn-LIP sediments are presented. Precious materials and data from dredging cruises and scientific ocean drilling expeditions have made this volume possible.

Download or read book Advances in 40Ar 39Ar Dating written by F. Jourdan and published by Geological Society of London. This book was released on 2014-04-02 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Decoding the complete history of Earth and our solar system requires the placing of the scattered pages of Earth history in a precise chronological order, and the 40Ar/39Ar dating technique is one of the most trusted dating techniques to do that. The 40Ar/39Ar method has been in use for more than 40 years, and has constantly evolved since then. The steady improvement of the technique is largely due to a better understanding of the K/Ar system, an appreciation of the subtleties of geological material and a continuous refinement of the analytical tools used for isotope extraction and counting. The 40Ar/39Ar method is also one of the most versatile techniques with countless applications in archaeology, tectonics, structural geology, orogenic processes and provenance studies, ore and petroleum genesis, volcanology, weathering processes and climate, and planetary geology. This volume is the first of its kind and covers methodological developments, modelling, data handling, and direct applications of the 40Ar/39Ar technique.

Download or read book Volcanism in Antarctica 200 Million Years of Subduction Rifting and Continental Break up written by J.L. Smellie and published by Geological Society of London. This book was released on 2021-06-09 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: This memoir is the first to review all of Antarctica’s volcanism between 200 million years ago and the Present. The region is still volcanically active. The volume is an amalgamation of in-depth syntheses, which are presented within distinctly different tectonic settings. Each is described in terms of (1) the volcanology and eruptive palaeoenvironments; (2) petrology and origin of magma; and (3) active volcanism, including tephrochronology. Important volcanic episodes include: astonishingly voluminous mafic and felsic volcanic deposits associated with the Jurassic break-up of Gondwana; the construction and progressive demise of a major Jurassic to Present continental arc, including back-arc alkaline basalts and volcanism in a young ensialic marginal basin; Miocene to Pleistocene mafic volcanism associated with post-subduction slab-window formation; numerous Neogene alkaline volcanoes, including the massive Erebus volcano and its persistent phonolitic lava lake, that are widely distributed within and adjacent to one of the world’s major zones of lithospheric extension (the West Antarctic Rift System); and very young ultrapotassic volcanism erupted subglacially and forming a world-wide type example (Gaussberg).