Download or read book The Isotope Geochemistry of Abyssal Peridotites and Related Rocks written by Jonathan E. Snow and published by . This book was released on 1993 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation studies several aspects of the formation of the Earth's oceanic mantle and crust, using a variety of geologic techniques, principally major elements, radiogenic isotopes and trace elements, but including petrography, mineral chemistry, x-ray diffraction, seafloor geomorphology, and analysis of the tectonics of fracture zones. The first chapter is an introduction to the problems to be addressed in this work. The second chapter examines the composition of basalts erupted near the Atlantis II Fracture Zone on the Southwest Indian Ridge. Trends in major element compositions of those basalts can be related directly to the nearby presence of the fracture zone. The effects of mantle composition and crustal level lateral transport of magma in the rift system can be ruled out by the analysis of isotopes and the geomorphology of the fracture zone floor. This is the best demonstration to date of a transform fault effect on basalt compositions. In trying to quantify putative transform fault effects documented at other fracture zones, no systematic correlation of transform offset age with mantle temperature change can be found, suggesting that mantle composition and lateral transport phenomena play a larger than expected role in the evolution of those areas. The third chapter relates to oceanic mantle rocks as they are altered at or near the Earth's surface. The major elements which make up abyssal peridotites are extensively redistributed by the alteration they have undergone. Mg is shown to be extracted from the peridotites, and a variety of trace elements added. This elemental redistribution is taken as evidence for extensive Mg transport by circulating waters. Since the solubility of Mg-bearing minerals in hydrothermal solutions is quite limited, much lower temperatures and much higher water /rock ratios are required to explain the major element compositions of the peridotites than had previously been assumed. The behavior of the Nd, Sr and Os isotopic systems during seafloor alteration was also studied. The isotope systematics of these rocks strongly support the hypothesis of high water /rock ratios in the formation of serpentinized abyssal peridotites. Nonetheless, Nd and Sr reside in a phase which is resistant to alteration (clinopyroxene) and the concentration of Os is high relative to that of seawater, so that it too appears resistant to alteration. Primary mantle isotopic signatures may be obtained from abyssal peridotites by careful analysis, even of extremely weathered rocks. Radiogenic strontium in excess of what could be introduced by seawater contamination or in situ radiogenic growth in a reasonable period of time was also found. These observations confirm earlier work which had been discredited for many years. The only plausible mechanism for the formation of this "orphan" S7Sr is that it is introduced as part of a sedimentary component which infiltrates the rock during metamorphism and/ or weathering. The 87Sr may be contained by or sorbed onto extremely fine clay particulates, or colloidal suspensions, as opposed to the dissolved ionic Sr which is normally thought of as characterizing the Sr isotopic composition of seawater. The high water/rock ratios required by the bulk isotopic analysis, as well as the pervasive elemental redistribution arguing for extensive near-surface weathering at high water /rock ra.tios strongly support this hypothesis. Given pervasive percolation of water throughout the samples, sufficient radiogenic, sediment-derived strontium may be drawn deep into the crust in the course of its weathering to cause such high B7SrfB6Sr ratios. The fourth chapter deals exclusively with primary mantle isotopic information from abyssal peridotites. This is the first study which has attempted to relate the Os isotopic system in the oceanic mantle to other isotopic systems and to trace elements. It is possible, with some extreme assumptions, to model the range of Os isotopes in the oceanic mantle alone in a standard model of formation of the depleted mantle by extraction of the crust. The additional constraints provided by the study of Nd isotopes in depleted mantle rocks from the oceans show that partial melt extraction and the formation of a depleted reservoir alone are not sufficient to account for the range of both N d and Os isotopes in the Earth's mantle. Possible mechanisms for the decoupling of the Os and Nd isotopic systems include elemental fractionation via the porous flow of basalt through the mantle, mantle metasomatism, recycling of a subducted component in the mantle and core formation. The core extraction model is pursued in some detail. Such core extraction models can account for the distributions and isotopic compositions of compatible and incompatible trace elements in the Earth's mantle, but they are highly non-unique, and thus difficult to test
Download or read book Petrological and Geochemical Studies of an Abyssal Periodotite from the Atlantis II Fracture Zone written by Kwok-Lin Lee and published by . This book was released on 1997 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the petrology and geochemistry of an abyssal peridotite dredged from the Atlantis II Fracture Zone in the southwestern Indian Ocean Ridge. Texturally, this sample is a serpentinized peridotite with a crosscutting coarse-grained clinopyroxenite vein. One of the alteration veinlets contains rutile and ilmenite in association with plagioclase and amphibole. This veinlet is not related to the pyroxenite vein. In tenns of mineralogy, the composition of the major silicate minerals indicates that this plagioclase llierzolite represents the depleted residue after mantle melting, similar to other abyssal peridotites from this region. In addition to the presence of the unique pyroxenite vein, this sample was earlier shown to be a carrier of 'orphan Sr-87'. Unfortunately, I was unable to find such high Sr isotopic ratios in the magnetic separations of different fractions of the sample. The sulfide mineralogy, together with the whole rock chemistry, suggests that sea water alteration occurs mainly as a result of serpentinization at temperatures higher than 200°C. Since the sample is less than l Ma old, and the low temperature weathering occurred only after the sample was exposed at the sea floor, it is possible that the weathering process was restricted to major alteration veins. This suggests that the alteration process is highly fracture controlled and time dependent Trace element data from clinopyroxene grains in the peridotite shows large variations from grain to grain. The (Ce/Yb)n ranges from 0.17 to 0.54 in the pyroxenite vein, and from 0.75 to 2.35 away from the vein. The tendency for LREE enrichment with the increase of distance from the vein suggests the presence of highly reacted melts. An assimilation-fractional crystallization (AFC) model was derived which supports the idea that the source of the clinopyroxenite vein reacts with the depleted peridotite to form a central reaction zone. Some of the highly reacted melt, after melt-rock reaction, migrates out of the reaction zone, and precipitates some late magmatic phases while being trapped in the country rocks. Since the sulfide is a major Os reservoir in the abyssal peridotites, as shown in leaching experiments, and the melt is saturated in sulfur as a consequence of the reaction process, it is possible to model the heterogeneous distribution of the Os isotopic data by mixing the residual peridotite with 0.2 to 0.5 wt% of sulfides precipitated from the melt. This mixing process can explain most of the heterogeneity from 1.034 to 1.148 for 187Os/186Os. The impact on the peridotite from the melt-rock reaction and impregnation of the late melt is obvious. As evident in Hess Deep gabbroic rocks, conductive heat loss in the transform fault fulfils the physical requirement to create and to preserve such geochemical signature.
Download or read book Neodymium Isotope Geochemistry written by Donald J. DePaolo and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph was begun with two objectives in mind. The first was to provide a review of research involving the application of neodymium isotopic measurements to pro blems in earth science. In the process of organizing to do this, I realized that the research in this field had produced a need for an updated review of the underlying paradigms. This need had arisen because of the special properties of the samarium-neodymium isotopic system, and because the research had transgressed the traditional boundaries be tween the subfields of earth science. Without such a review, the significance of the results seemed likely to remain un necessarily obscure to interested scientists from related disciplines. Consequently, the second objective became the provision of a theoretical framework for the application of neodymium isotopic studies. Much of what this contains is not new, but it is drawn together here for the first time. At the time the writing was initiated, the literature of the field was still relatively limited. Over the past 5 years it has grown enormously. Considering the rate at which the writing progressed, it became clear that this could not be a fully up-to-date review and still reach completion. The selection of material for the review sections is biased toward earlier studies. Part I presents most of the background information.
Download or read book Isotope Geochemistry written by William M. White and published by John Wiley & Sons. This book was released on 2014-11-03 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to radiogenic andstable isotope geochemistry. Beginning with a brief overview ofnuclear physics and nuclear origins, it then reviews radioactivedecay schemes and their use in geochronology. A following chaptercovers the closely related techniques such as fission-track andcarbon-14 dating. Subsequent chapters cover nucleosyntheticanomalies in meteorites and early solar system chronology and theuse of radiogenic isotopes in understanding the evolution of theEarth’s mantle, crust, and oceans. Attention then turns tostable isotopes and after reviewing the basic principles involved,the book explores their use in topics as diverse as mantleevolution, archeology and paleontology, ore formation, and,particularly, paleoclimatology. A following chapter explores recentdevelopments including unconventional stable isotopes,mass-independent fractionation, and isotopic‘clumping’. The final chapter reviews the isotopicvariation in the noble gases, which result from both radioactivedecay and chemical fractionations.
Download or read book Stable Isotope Geochemistry written by Jochen Hoefs and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first edition of this book was published in 1973, the second, totally rewritten, followed 7 years later in 1980. Because the field of stable isotopes is still grow ing and exerting an increasing influence on geosciences in general, it seems to be necessary, after a further 7 years, to revise the edition again accordingly. Not only has the previous edition been updated, but two completely new chapters on the isotopic composi tion of mantle-derived material and on the isotopic composition of the ocean during the geologie past, have been added. The references concentrate on re cent literature. In some cases, older references have been omitted to save space. I do not intend to underrate the value of older publications, but only to keep the reference list - al ready very voluminous in relation to the totallengt- from becoming even larger. An early draft has been reviewed by Russell Harmon and Alan Matthews. John Valley has se nt me a preprint of an artic1e on metamorphie rocks. To all three of them I owe my deepest thanks.
Download or read book Stable Isotope Geochemistry written by J. Hoefs and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Lectures in Isotope Geology written by E. Jäger and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our colleagues from the French-speaking parts of Switzerland - the Suisses romands - and above all the committee of the 3rd Cycle, e Earth Sciences (3 Cycle, Sciences de la Terre) honored us by asking us to give a course on Isotope Geology for the year 1977. The course, entitled Evaluation et Interpretation des Donnees Isotopiques (eval uation and Interpretation of Isotopic Data), was intended to inform earth scientists, graduate and postgraduate, from the western Swiss Universities on the subject of Isotope Geology. Such courses usually consist of two parts: lectures and excursions. Thus, in March 1977, we gave such a two-week course at the Miner alogical Institute of the University of Berne. The first week was devoted essentially to the methods of dating, the second week to the behavior of stable isotopes. In July 1977, on the occasion of an excursion to the Central and Western Alps, we were able to demonstrate our results. Guest professors were invited to make contributions to the course.
Download or read book Stable Isotope Geochemistry written by John W. Valley and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 43 of Reviews in Mineralogy and Geochemistry follows the 1986 Reviews in Mineralogy (Vol. 16) in approach but reflects significant changes in the field of Stable Isotope Geochemistry. In terms of new technology, new sub-disciplines, and numbers of researchers, the field has changed more in the past decade than in any other since that of its birth. Unlike the 1986 volume, which was restricted to high temperature fields, this book covers a wider range of disciplines. However, it would not be possible to fit a comprehensive review into a single volume. Our goal is to provide state-of-the-art reviews in chosen subjects that have emerged or advanced greatly since 1986. This volume was prepared for Short Course on Stable Isotope Geochemistry presented November 2-4, 2001 in conjunction with the annual meetings of the Geological Society of America in Boston, Massachusetts.
Download or read book Radiogenic Isotope Geology written by Alan P. Dickin and published by Cambridge University Press. This book was released on 2018-02-08 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: The new edition of Radiogenic Isotope Geology examines revolutionary changes in geochemical thinking, evaluating them in historical context.
Download or read book The Geochemistry and Geophysics of the Antarctic Mantle written by A.P. Martin and published by Geological Society of London. This book was released on 2023-02-14 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Memoir is the first dedicated to the Antarctic mantle. It is a cross-disciplinary reference work combining geochemistry and geophysics to characterize Antarctic mantle properties. Through observations and modelling the mantle structures, compositions and dynamics are characterized at regional and continental scales by subject experts. The Memoir reviews all known occurrences of sub-continental mantle xenoliths in igneous rocks. These studies are presented by region as southern or northern Victoria Land, Marie Byrd Land, the Antarctic Peninsula, East Antarctica and the sub-Antarctic Islands. Sub-oceanic mantle in tectonically emplaced and abyssal settings is also considered where known. This is complemented by a continental-scale mantle xenolith overview, mantle characteristics from igneous rocks and a quantitative mantle fabric study. State-of-the-art, continental-scale geophysical overviews of the Antarctic mantle are presented by discipline as seismology, gravity and magnetics, magnetotellurics, rheology, glacial isostatic adjustment, mantle convection and palaeotopography. This Memoir will be the reference for all researchers interested in the Antarctic mantle and its role in dynamics that shape the Antarctic surface and ice sheets.
Download or read book Isotope Geochemistry written by William M. White and published by John Wiley & Sons. This book was released on 2023-02-13 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: ISOTOPE GEOCHEMISTRY Provides a thorough and up-to-date overview of radiogenic and stable isotope geochemistry Now in its second edition, Isotope Geochemistry presents a comprehensive introduction to radiogenic and stable isotope geochemistry. The first five chapters cover fundamentals including the physics of nuclei, radioactive decay, nucleosynthesis, geochronology, and the theory of stable isotope fractionation. The next chapter focuses on the isotope geochemistry of meteorites and their constraints on the formation of the solar system and the Earth. The subsequent three chapters cover radiogenic and stable isotope geochemistry evolution of the Earth’s mantle and crust. Three more chapters are devoted to the Earth’s surface, the exogene, including the hydrologic system, the biosphere, and climate. A new chapter in this edition focuses on the use of isotopes in paleontology and archeology. The final chapter is devoted to the isotope geochemistry of the noble gases. Illustrated in full color throughout, Isotope Geochemistry is intended primarily as a textbook for advanced undergraduate and graduate students. It is also intended as a reference for earth science professionals, reflecting the impact that isotope geochemistry has on virtually every aspect of the earth sciences, from climate change and geomorphology to geodynamics.
Download or read book Stable Isotopes in High Temperature Geological Processes written by John W. Valley and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 16 of Reviews in Mineralogy inroduces to high-temperature stable isotope geochemistry and should provide an entry into the pertinent literature, as well as some understanding of the basic concepts and potential applications. The first three chapters focus on the theory and experimental data base for equilibrium, disequilibrium, and kinetics of stable isotope exchange reactions among geologically important minerals and fluids. The fourth chapter discusses the primordial oxygen isotope variations in the solar system prior to formation of the Earth, along with a discussion of isotopic anomalies in meteorites. The fifth chapter discusses isotopic variations in the Earth's mantle and the sixth chapter reviews the variations in the isotopic compositions of natural waters on our planet. In Chapters 7, 8, 9 and 10, these isotopic constraints and concepts are applied to various facets of the origin and evolution of igneous rocks, bringing in much material on radiogenic isotopes as well, because these problems require a multi-dimensional attack for their solution. In Chapters 11 and 12, the problems of hydrothermal alteration by meteoric waters and ocean water are considered, together with discussions of the physics and chemistry of hydrothermal systems and the 18O/16O history of ocean water. Finally, in Chapters 13 and 14, these concepts are applied to problems of metamorphic petrology and ore deposits, particularly with respect to the origins of the fluids involved in those processes.
Download or read book Subseafloor Biosphere Linked to Hydrothermal Systems written by Jun-ichiro Ishibashi and published by Springer. This book was released on 2015-01-10 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the comprehensive volume of the TAIGA (“a great river ” in Japanese) project. Supported by the Japanese government, the project examined the hypothesis that the subseafloor fluid advection system (subseafloor TAIGA) can be categorized into four types, TAIGAs of sulfur, hydrogen, carbon (methane), and iron, according to the most dominant reducing substance, and the chemolithoautotrophic bacteria/archaea that are inextricably associated with respective types of TAIGAs which are strongly affected by their geological background such as surrounding host rocks and tectonic settings. Sub-seafloor ecosystems are sustained by hydrothermal circulation or TAIGA that carry chemical energy to the chemosynthetic microbes living in an extreme environment. The results of the project have been summarized comprehensively in 50 chapters, and this book provides an overall introduction and relevant topics on the mid-ocean ridge system of the Indian Ocean and on the arc-backarc systems of the Southern Mariana Trough and Okinawa Trough.
Download or read book Magma Redox Geochemistry written by Roberto Moretti and published by John Wiley & Sons. This book was released on 2021-10-26 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the many facets of redox exchanges that drive magma's behavior and evolution, from the origin of the Earth until today The redox state is one of the master variables behind the Earth's forming processes, which at depth concern magma as the major transport agent. Understanding redox exchanges in magmas is pivotal for reconstructing the history and compositional make-up of our planet, for exploring its mineral resources, and for monitoring and forecasting volcanic activity. Magma Redox Geochemistry describes the multiple facets of redox reactions in the magmatic realm and presents experimental results, theoretical approaches, and unconventional and novel techniques. Volume highlights include: Redox state and oxygen fugacity: so close, so far Redox processes from Earth’s accretion to global geodynamics Redox evolution from the magma source to volcanic emissions Redox characterization of elements and their isotopes 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 Highly Siderophile and Strongly Chalcophile Elements in High Temperature Geochemistry and Cosmochemistry written by Jason Harvey and published by Walter de Gruyter GmbH & Co KG. This book was released on 2016-03-07 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highly Siderophile and Strongly Chalcophile Elements in High Temperature Geochemistry and Cosmochemistry, Volume 81 This RiMG (Reviews in Mineralogy & Geochemistry) volume investigates the application of highly siderophile (HSE) and strongly chalcophile elements. This volume has its origin in a short course sponsored by the Mineralogical Society of America and the Geochemical Society held in San Diego, California on the 11th and 12th December 2015, ahead of the American Geophysical Union’s Fall Meeting, which featured a session with the same title. Topics in this volume include: analytical methods and data quality experimental constraints applied to understanding HSE partitioning nucleosynthetic variations of siderophile and chalcophile elements HSE in the Earth, Moon, Mars and asteroidal bodies HSE and chalcophile elements in both cratonic and non-cratonic mantle, encompassing both sub-continental and sub-oceanic lithosphere the importance of the HSE for studying volcanic and magmatic processes, and an appraisal of the importance of magmatic HSE ore formation in Earth’s crust. Highly siderophile and strongly chalcophile elements comprise Re, Os, Ir, Ru, Pt, Rh, Pd, Au, Te, Se and S and are defined by their strong partitioning into the metallic phase, but will also strongly partition into sulfide phases, in the absence of metal. The chemical properties of the HSE mean that they are excellent tracers of key processes in high temperature geochemistry and cosmochemistry, having applications in virtually all areas of earth science. A key aspect of the HSE is that three long-lived, geologically useful decay systems exist with the HSE as parent (107Pd-107Ag), or parent-daughter isotopes (187Re-187Os and 190Pt-186Os). The material in this book is accessible for graduate students, researchers, and professionals with interests in the geochemistry and cosmochemistry of these elements, geochronology, magmatic ore bodies and the petrogenesis of platinum-group minerals.