Download or read book Geochemical and Fluid Dynamic Investigations Into the Nature of Chemical Heterogeneity in the Earth s Mantle written by Erik Harold Hauri and published by . This book was released on 1992 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: Variations in the abundances of elements and radiogenic isotopes in mantle derived peridotites and volcanic rocks are chemical integrals over time, space, and process, which ultimately contain information about the role of convection in the earth's mantle in creating, maintaining, and destroying geochemical heterogeneities. Successful inversion of these integrals requires extensive knowledge of the geochemical behavior of elements, the length scales of chemical variability, the evolution with time of geologic systems, the physical properties of mantle rocks, and the driving forces of phenomena which govern heat and mass transport in a dynamic earth. This dissertation attempts to add to this knowledge by examining the trace element and isotope geochemistry of mantle peridotites and oceanic island basalts, and by studying aspects of the flow of viscous fluids driven by thermal buoyancy. The trace element and isotopic systematics of peridotites and associated mafic layers from the Ronda Ultramafic Complex, southern Spain (Chapter 2), provides information bearing on the geochemical behavior of the highly incompatible elements U, Th, and Pb in the mantle, and on the length scales of geochemical variability in a well exposed peridotite massif. Garnet is demonstrated to be a significant host for U in the mantle, and together with clinopyroxene, these two minerals control the abundances and partitioning relationships of U and Th during the melting of anhydrous peridotite. Clinopyroxene, plagioclase, and to a lesser extent garnet are hosts for Pb in mantle peridotite; however, the role of trace sulfide may exert some control over the abundance and partitioning of Pb in some samples. Due to the possibility that Pb is partitioned into sulfide, the U/Pb, Th/Pb, and Ce/Pb ratios measured in clinopyroxene are likely to be higher than the bulk rock. U-Pb age systematics of garnet-clinopyroxene pairs from Ronda peridotites and mafic layers indicate Pb isotopic equilibrium in these samples up to 20-50 Ma ago. The Pb-Pb systematics of garnet- and spinel-facies peridotites and mafic layers indicate a heterogeneity on the order of 3 Ga old. This Pb isotope signature may have been created within the massif 3 Ga ago, or may have been metasomatically imprinted on the massif 1.3 Ga ago by basaltic melts with island arc affinities. The isotopic evolution of Ronda is consistent with at 1.3 Ga ago, and was subsequently incorporated into the subcontinental lithosphere. The very low U, Th, and Pb concentrations in depleted peridotite indicate that recycled crustal materials, with U-Th-Pb concentrations 102-104 times higher than peridotite, will have a larger influence on the isotopic composition of Pb in the mantle than on the Sr and Nd isotopic composition. An investigation of the trace element and isotopic compositions of clinopyroxenes in peridotite xenoliths from Savaii, Western Samoa and Tubuai, Austral Islands (Chapter 3) reveals geochemical signatures which are not present in basalts from these islands, due to the inherent averaging of melting processes. The data indicate similarities in the melting and melt segregation processes beneath these isotopically extreme islands. Samples with LREE depleted clinopyroxenes, with positive Zr and negative Ti anomalies, are the result of poly baric fractional melting of peridotite in the garnet- and spinel lherzolite stability fields, with the Savaii samples having experienced a larger mean degree of melting than the Tubuai samples. The extreme fractionation of HREE in the Savaii samples requires that they have melted to the clinopyroxene-out point (about 20%) while retaining residual garnet; the low concentrations ofHREE in these same samples requires a further 10-20% melting in the spinel lherzolite stability field. The extremely high total degrees of melting experienced by the Savaii samples (33-42%), as well as the high degree of melting in the garnet lherzolite stability field, suggests a mantle plume origin for these xenoliths. A large majority of the xenolith clinopyroxenes from both Savaii and Tubuai are LREE enriched to varying degrees, and many samples display significant intergrain trace element heterogeneity. This highly variable yet systematic heterogeneity was the result of metasomatism by percolating melts undergoing chromatographic trace element fractionation. The trace element compositions of some LREE enriched clinopyroxenes are consistent with the percolating melt being typical oceanic island basalt. The clinopyroxenes with the highest LREE concentrations from both islands, which also have very low Ti and Zr concentrations and large amounts of grain-boundary hosted Ba, require that the percolating melt in these cases had the trace element signature of carbonatite melt. The isotopic composition of one of these "carbonatitic" samples from Tubuai is similar to basalts from this island. The isotopic composition of clinopyroxene in a "carbonatitic" sample from Savaii records 87Sr/86Sr and l43Nd/l44Nd values of .71284 and .512516 respectively, far in excess of the most extreme Samoa basalt values (87Sr/86Sr=.70742, 143Nd/l44Nd=.51264). These "carbonatitic" signatures indicate the presence of volatilerich, isotopically extreme components in the mantle beneath Tubuai and Savaii, which likely have their origins in recycled crustal materials. The Re-Os isotope systematics of oceanic island basalts from Rarotonga, Savaii, Tahaa, Rurutu, Tubuai, and Mangaia are examined (Chapter 4). Os concentration variations suggest that olivine, or a low Re/Os phase associated with olivine, controls the Os concentration in basaltic magmas. The Savaii and Tahaa samples, with high 87Sr/86Sr and 207Pb/204Pb ratios (EMII), as well as basalts from Rarotonga, have 1870s/1860s ratios of 1.026-1.086, within the range of estimates of bulk silicate earth and depleted upper mantle. The basalts from Rurutu, Tubuai, and Mangaia (Macdonald hotspot), characterized by high Pb isotope ratios (HIMU), have 1870sfl860s ratios of 1.117-1.248, higher than any estimates for bulk silicate earth, and higher than Os isotope ratios of metasomatized peridotites. The high 1870s/1860s ratios indicate the presence of recycled oceanic crust in the mantle sources of Rurutu, Tubuai, and Mangaia. Inversion of the isotopic data for Mangaia (endmember HIMU) indicate that the recycled crustal component has Rb/Sr, Sm/Nd, Lu/Hf, and Th/U ratios which are very similar to fresh MORB glasses, and U/Pb and Th/Pb ratios which are within the range of MORB values, but slightly higher than average N-MORB. These results indicate that the low-temperature alteration signature of altered oceanic crust may be largely removed during subduction, and that oceanic crust was recycled into to the lower mantle source of the Macdonald hotspot plume. Furthennore, the high 187Os/l86Os ratios of the Tubuai and Mangaia basalts indicates that percolation through depleted mantle peridotite (187Os/186Qs=1.00-1.08), observed to occur in the Tubuai xenoliths, had little influence on the composition of the erupted basalts. A fluid dynamic model for mantle plumes is developed (Chapter 5) by examining a vertical, axisymmetric boundary layer originating from a point source of heat, and incorporating experimentally constrained rheological and physical properties of the mantle. Comparison of linear (n=l) and non-Newtonian (olivine, n=3) rheologies reveals that non-Newtonian plumes have narrower radii and higher vertical velocities than corresponding Newtonian plumes. The non-Newtonian plumes also exhibit "plug flow" at the conduit axis, providing a mechanism for the transport of deep mantle material, through the full depth of the mantle, in an unmixed state. Plumes are demonstrated to entrain ambient mantle via the horizontal conduction of heat, which increases the buoyancy and lowers the viscosity of mantle at the plume boundary. Streamlines calculated from the fluid dynamic model demonstrate that most of the entrained mantle originates from below 1500 km depth. Parameterization of the entrainment mechanism indicates that the factional amount of entrained mantle is lower in stronger, hotter plumes due to their higher vertical velocities. Examination of the global isotopic database for oceanic island basalts reveals the presence of a mantle component (FOZO), common to many hotspots worldwide, characterized by depleted 87Sr/86Sr and 143Nd/l44Nd, radiogenic 206,207,208Pb/204Pb, and high 3He/4He. This component is isotopically distinct from the source of MORB; thus, with the exception of ridge centered hotspots such as Iceland and the Galapagos, upper mantle does not appear to be a component in most hotspots, in agreement with entrainment theory. The combined fluid dynamic and isotopic results indicate that both FOZO and the enriched mantle components (EMI, EMil, and HIMU) are located in the lower mantle. Furthermore, high 3He/4He in FOZO precludes an origin for FOZO-bearing plumes in a thermal boundary layer at 670 km depth in the mantle. Since a 670 km thermal boundary layer would be replenished by the downward motion of the upper mantle, an origin for FOZO at 670 km would require either 1) a high 3He/4He signature in the MORB source, or 2) entrainment of MORB mantle into intraplate plumes, neither of which is observed in the OIB isotope data. This indicates that the 670 km discontinuity is not a barrier to mantle convection. The preservation of isotopically different upper and lower mantles does not require layered convection, but is probably the result of an increasing residence time with depth in the mantle, possibly caused by an increase in the mean viscosity of the mantle with depth

Download or read book The Earth s Heterogeneous Mantle written by Amir Khan and published by Springer. This book was released on 2015-04-28 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights and discusses recent developments that have contributed to an improved understanding of observed mantle heterogeneities and their relation to the thermo-chemical state of Earth's mantle, which ultimately holds the key to unlocking the secrets of the evolution of our planet. This series of topical reviews and original contributions address 4 themes. Theme 1 covers topics in geophysics, including global and regional seismic tomography, electrical conductivity and seismic imaging of mantle discontinuities and heterogeneities in the upper mantle, transition zone and lower mantle. Theme 2 addresses geochemical views of the mantle including lithospheric evolution from analysis of mantle xenoliths, composition of the deep Earth and the effect of water on subduction-zone processes. Theme 3 discusses geodynamical perspectives on the global thermo-chemical structure of the deep mantle. Theme 4 covers application of mineral physics data and phase equilibrium computations to infer the regional-scale thermo-chemical structure of the mantle.

Download or read book Treatise on Geophysics Volume 7 written by David Bercovici and published by Elsevier. This book was released on 2010-05-17 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Treatise on Geophysics: Mantle Dynamics, Volume 7 aims to provide both a classical and state-of-the-art introduction to the methods and science of mantle dynamics, as well as survey leading order problems (both solved and unsolved) and current understanding of how the mantle works. It is organized around two themes: (1) how is mantle convection studied; and (2) what do we understand about mantle dynamics to date. The first four chapters are thus concerned with pedagogical reviews of the physics of mantle convection; laboratory studies of the fluid dynamics of convection relevant to the mantle; theoretical analysis of mantle dynamics; and numerical analysis and methods of mantle convection. The subsequent chapters concentrate on leading issues of mantle convection itself, which include the energy budget of the mantle; the upper mantle and lithosphere in and near the spreading center (mid-ocean ridge) environment; the dynamics of subducting slabs; hot spots, melting anomalies, and mantle plumes; and finally, geochemical mantle dynamics and mixing. - 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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Treatise on Geophysics written by and published by Elsevier. This book was released on 2015-04-17 with total page 5604 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Treatise on Geophysics Volume 2 written by G David Price and published by Elsevier. This book was released on 2010-04-20 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: Treatise on Geophysics: Mineral Physics, Volume 2, provides a comprehensive review of the current state of understanding of mineral physics. Each chapter demonstrates the significant progress that has been made in the understanding of the physics and chemistry of minerals, and also highlights a number of issues which are still outstanding or that need further work to resolve current contradictions. The book first reviews the current status of our understanding of the nature of the deep Earth. These include the seismic properties of rocks and minerals; problems of the lower mantle and the core-mantle boundary; and the state of knowledge on mantle chemistry and the nature and evolution of the core. The discussions then turn to the theory underlying high-pressure, high-temperature physics, and the major experimental methods being developed to probe this parameter space. The remaining chapters explain the specific techniques for measuring elastic and acoustic properties, electronic and magnetic properties, and rheological properties; the nature and origin of anisotropy in the Earth; the properties of melt; and the magnetic and electrical properties of mantle phases. - 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

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 Bibliography of Technical Reports written by Woods Hole Oceanographic Institution and published by . This book was released on 1992 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geochemistry written by Harry Y. McSween and published by Columbia University Press. This book was released on 2003 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written expressly for undergraduate and graduate geologists, this book focuses on how geochemical principles can be used to solve practical problems. The attention to problem-solving reflects the authors'belief that showing how theory is useful in solving real-life problems is vital for learning. The book gives students a thorough grasp of the basic principles of the subject, balancing the traditional equilibrium perspective and the kinetic viewpoint. The first half of the book considers processes in which temperature and pressure are nearly constant. After introductions to the laws of thermodynamics, to fundamental equations for flow and diffusion, and to solution chemistry, these principles are used to investigate diagenesis, weathering, and natural waters. The second half of the book applies thermodynamics and kinetics to systems undergoing changes in temperature and pressure during magmatism and metamorphism. This revised edition incorporates new geochemical discoveries as examples of processes and pathways, with new chapters on mineral structure and bonding and on organic matter and biomarkers. Each chapter has worked problems, and the authors assume that the student has had a year of college-level chemistry and a year of calculus. Praise for the first edition "A truly modern geochemistry book.... Very well written and quite enjoyable to read.... An excellent basic text for graduate level instruction in geochemistry." --Journal of Geological Education "An up-to-date, broadly conceived introduction to geochemistry.... Given the recent flowering of geochemistry as an interdisciplinary science, and given the extent to which it now draws upon the fundamentals of thermodynamics and kinetics to understand earth and planetary processes, this timely and rigorous [book] is welcome indeed." --Geochimica et Cosmochimica Acta

Download or read book Treatise on Geochemistry written by and published by Newnes. This book was released on 2013-10-19 with total page 14787 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!

Download or read book Treatise on Geophysics Volume 8 written by Peter L. Olson and published by Elsevier. This book was released on 2010-05-18 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Treaties on Geophysics: Core Dynamics, Volume 8, provides a comprehensive review of the current state of understanding of core dynamics. The book begins by analyzing a subject of long-standing and on-going controversy: the gross energetics of the core. It then explains the important elements of dynamo theory; actual fluid motions in the core; the basic physical principles involved in thermochemical convection in the core and the basic equations governing the convection; and turbulence and the small-scale dynamics of the core. This is followed by discussions of the state of knowledge on rotation-induced core flows; the use of first-principles numerical models of self-sustaining fluid dynamos; and the behavior of polarity reversals in numerical dynamo models. The remaining chapters cover the various roles the inner core plays in core dynamics and the geodynamo; experiments that have shaped knowledge about the flows in the core that produce the geodynamo and govern its evolution; and ways the mantle can affect core dynamics, and corresponding ways the core can affect the mantle. - 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

Download or read book Advances in Geochemistry Analytical Chemistry and Planetary Sciences written by Vladimir P. Kolotov and published by Springer Nature. This book was released on 2023-02-28 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents 41 selected articles written by leading researchers from the Vernadsky Institute of Geochemistry and Analytical Chemistry, part of the Russian Academy of Sciences. The articles are grouped by the following topics: (1) Geochemistry, (2) Meteoritics, Cosmochemistry, Lunar and Planetary Sciences, (3) Biogeochemistry and Ecology, and (4) Analytical Chemistry, Radiochemistry, and Radioecology. The articles present recent experimental data, theoretical investigations, critical reviews, the results of computer modeling in the above-mentioned fields. Intended to provide a scientific “snapshot” of the institute, the book also includes content on its history, main scientific achievements and current goals, together with detailed descriptions of its 25 laboratories and three museums so as to promote new international collaborations. Given its scope, the book will be of interest to all scientists and graduate students working in the areas of geochemistry, analytical chemistry and radiochemistry, earth and environmental sciences, biogeosciences, meteoritics and planetary science, and to those seeking new collaboration opportunities in these areas in Russia.

Download or read book Core Mantle Co Evolution written by Takashi Nakagawa and published by John Wiley & Sons. This book was released on 2023-06-27 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 Mantle Plumes written by Richard E. Ernst and published by Geological Society of America. This book was released on 2001-01-01 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Encyclopedia of Solid Earth Geophysics written by Harsh Gupta and published by Springer Science & Business Media. This book was released on 2011-06-29 with total page 1579 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past few decades have witnessed the growth of the Earth Sciences in the pursuit of knowledge and understanding of the planet that we live on. This development addresses the challenging endeavor to enrich human lives with the bounties of Nature as well as to preserve the planet for the generations to come. Solid Earth Geophysics aspires to define and quantify the internal structure and processes of the Earth in terms of the principles of physics and forms the intrinsic framework, which other allied disciplines utilize for more specific investigations. The first edition of the Encyclopedia of Solid Earth Geophysics was published in 1989 by Van Nostrand Reinhold publishing company. More than two decades later, this new volume, edited by Prof. Harsh K. Gupta, represents a thoroughly revised and expanded reference work. It brings together more than 200 articles covering established and new concepts of Geophysics across the various sub-disciplines such as Gravity, Geodesy, Geomagnetism, Seismology, Seismics, Deep Earth Processes, Plate Tectonics, Thermal Domains, Computational Methods, etc. in a systematic and consistent format and standard. It is an authoritative and current reference source with extraordinary width of scope. It draws its unique strength from the expert contributions of editors and authors across the globe. It is designed to serve as a valuable and cherished source of information for current and future generations of professionals.

Download or read book The Interdisciplinary Earth In Honor of Don L Anderson written by Gillian R. Foulger and published by Geological Society of America. This book was released on 2015-09 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Copublished with the American Geophysical Union as American Geophysical Union Special Publication 71 This volume is a memorial to Don L. Anderson, former director of the Seismological Laboratory of the Caltech Institute of Technology, recipient of the Crafoord Prize, the National Medal of Honor, and numerous other awards. A geophysicist extraordinaire, he contributed much to our understanding of the structure and dynamics of the interior of Earth. The book, comprised largely of chapters written at Anderson's invitation, reflects his interdisciplinary career. It includes papers on anisotropy, the seismic structure of the mantle, mantle convection, the statistics of melting anomalies, planetary geology, tectonics, the thermal budget of Earth, lithospheric structure, geochemistry, and flood basalts.

Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1836 pages. Available in PDF, EPUB and Kindle. Book excerpt: