Download or read book Partitioning of Elements Between Silicate Melt and Salt Water at Mantle Conditions written by John C. Ayers and published by . This book was released on 1988 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Silicate Melt Under Pressure written by Eleanor Rose Mare and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many geochemical models of magmatic processes, such as the formation of the Earth's metallic core, are based on trace element partition coefficients. Fundamental to these models is an understanding of how partition coefficients vary with pressure. The main objective of this thesis is to explore one factor that controls the pressure-dependence of partitioning: the coordination environment (i.e. the number of bonded oxygens) of cations in silicate melt. Changes in the coordination number of major elements, Si and Al, are well known to occur in natural melts with pressure, but similar changes have been demonstrated for only a few trace elements: Ni, Co and Lu. In this work, coordination environments of Ge were Ga were studied. X-ray absorption spectroscopy of aluminosilicate glasses was used to show that both Ge and Ga begin to change their coordination from about 1 GPa, and this change is not yet complete at 10 GPa. In glasses quenched from high-pressure melts, Ge and Ga average coordination increased rapidly between 4 and 5 GPa, suggesting that a change in major element coordination might influence the coordination of both trace elements. To assess this possibility, nuclear magnetic resonance spectroscopy was used to determine changes in the local environments of major elements in the same or similar glasses to which Ge and Ga coordination was studied. Al coordination changed rapidly between 4 and 5 GPa, as had been observed for Ge and Ga. In particular, the Ga and Al average coordination numbers correlate well. These observations indicate that changes in the coordination of major elements may indeed influence the coordination of trace elements. The effect of a Ge coordination change on partitioning was determined by conducting olivine-melt partitioning experiments up to 4.5 GPa. The results show that Ge becomes more incompatible with increasing pressure, whereas if no coordination change took place, the opposite behaviour would be expected. However, existing models are insufficient to describe the effect of coordination changes on partitioning behaviour. The observed coordination changes of Ge4+ will be relevant in models of the Earth's core formation only if Ge4+ is the stable species at the reducing conditions of the magma ocean at that time (below the iron-wüstite oxygen buffer, IW). However, previous work has indicated the possibility of Ge2+ stability in silicate melts around these conditions. This was tested using X-ray absorption spectroscopy of glasses quenched from melts prepared at varying oxygen fugacity. The spectra show that the Ge4+-Ge2+ transition occurs over the range IW +2 to IW -2. Olivine-melt partitioning experiments indicate that Ge2+ is highly incompatible, in contrast to Ge4+, which has a partition coefficient close to one.
Download or read book Trace Element Geochemistry of Oceanic Peridotites and Silicate Melt Inclusions written by Kevin Todd Michael Johnson and published by . This book was released on 1990 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mantle melting process is fundamental to basalt genesis and crustal accretion at mid-ocean ridges. It is believed that melts ascend more rapidly than the surrounding mantle, implying a process similar to fractional melting may be occurring, but geochemical evidence for this has been lacking. Furthermore, crustal accretion is thought to be episodic at slow spreading ridges, but sampling programs that can test this temporal variability are virtually nonexistent. This dissertation examines the trace element compositions of abyssal peridotites and discusses how they preserve details of the melting process that are not recognizable in mid-ocean ridge basalts. The results support fractional melting as the dominant melting process in the sub-ridge upper mantle. Evidence is also presented supporting non-steady state mantle melting at the Atlantis II Fracture Zone cutting the very slow spreading Southwest Indian Ridge. Trace element compositions of peridotite clinopyroxenes from fracture zones along the American-Antarctic and Southwest Indian Ridges vary as a function of proximity to hotspots. The results presented in Chapter 2 are consistent with higher degrees of melting and greater incompatible element depletion in the upper mantle near hotspots. All peridotites studied are consistent with being residues of fractional melting and inconsistent with batch melting. Some samples recovered near hotspots appear to have begun melting in the garnet stability field, deeper than samples recovered away from hotspots. Most samples show pronounced negative Zr and Ti anomalies, which increase with increasing incompatible element depletion (increased melting), on extended rare earth (spider) diagrams. The results of Chapter 2 indicated the importance of accurately knowing trace element partition coefficients between clinopyroxene and liquid. It was found that existing partitioning studies report either rare earth elements, Ti, or Zr, but not all elements together. Thus, there is ambiguity about relative partition coefficients for these elements. Accurate knowledge of partitioning is important in understanding the formation of negative Zr and Ti anomalies observed in peridotite clinopyroxenes as well as in constructing realistic melting models for peridotites. To that end, Chapter 3 reports the results of a clinopyroxene/basaltic liquid trace element partitioning study carried out on natural dredged basalts and experimental charges of mid-ocean ridge basalts. It was found that there are small negative anomalies in the partiton coefficients of Zr and Ti relative to adjacently plotted rare earth elements on spider diagrams. Fractional melting implies that small parcels of refractory (e.g., high Mg/[Mg+Fe]), incompatible element depleted melts must exist somewhere in the ascending body of melt. Since mixing, wall rock reaction, and fractional crystallization probably alter the compositions of silicate melts extensively on their way from source to surface, representatives of these refractory fractional melts will rarely be erupted as flows on the seafloor. However, some refractory silicate melt inclusions possess compositional characteristics akin to those expected in fractional melts, i.e. low incompatible element concentrations and fractionated trace element ratios. Chapter 4 is a study of refractory melt inclusions from a variety of tectonic settings. The inclusions were obtained from Dr. A.V. Sobolev of the Vernadsky Institute of Geochemistry, Soviet Academy of Sciences, Moscow. They are not ideally suited for studying mid-ocean ridge processes, as only a few of the inclusions are from this environment, but in general, the inclusions show more refractory, incompatible element depleted compositions than their host lavas. Furthermore, the suite of inclusions in different mineral phases contained in a single N-type mid-ocean ridge basalt show variable trace element characteristics indicating unrelated sources for some inclusions. The results of the study do not strongly endorse the fractional melting hypothesis, but some support is suggested by trace element depletions and fractionations warranting a more thorough study of a suite of inclusions. Finally, the along-ridge major and trace element variability in peridotites observed previously and in Chapter 2 is compared to the variability found in a single fracture zone. The high sampling density at the Atlantis IT Fracture Zone on the Southwest Indian Ridge, coupled with its great distance from a hotspot make it a good subject for a baseline study. It was found that the compositional variability observed in peridotites from the Atlantis II Fracture Zone covers nearly the whole range of compositions found along the AmericanAntarctic and Southwest Indian Ridges in Chapter 2. However, there are systematics to this wide range, suggesting different processes may control the depletions. On the eastern side of the transform, a compositional gradient is observed from the center of the eastern wall to the northern ridge-transform intersection. Peridotites on this side have become gradually more depleted in incompatible elements and modal clinopyroxene over at least the last 10-11 million years. Samples from the western side of the transform are, in general, more depleted than those from the eastern side and show some indication of a compositional gradient as well, although sampling is less dense. Basalts from the western side are clearly different in iron composition and degree of rare earth element fractionation. These differences are consistent with higher pressure, higher degrees of melting producing lavas on the western side. It is believed that the long wavelength chemical variations corresponding to hotspot proximity described in Chapter 2 result from regional thermal conditions in the upper mantle imposed, in large part, by the hotspots. On the other hand, the short wavelength variability on a fracture zone or spreading cell scale may result from episodic mantle upwelling and magma production due to non-steady state accretion at very slow spreading ridges.
Download or read book Trace Element Partitioning Between a Silicate Melt and a Super critical Hydrous Fluid written by Elizabeth Jean Fregeau and published by . This book was released on 1985 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Partitioning of Rare earth Elements Among Rock forming Silicate Phases and Water written by Robert Lee Cullers and published by . This book was released on 1971 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Behaviour of the Trace Elements in the Silicate Melts of the Earth s Mantle written by Alexandra Catalina Seclaman and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We explore Fe-bearing Mg-silicate melts through the pressure regime of the Earth's mantle using First Principles Molecular Dynamics (FPMD). The equation of state results we obtained from our simulations are used to create a chemical and mineralogical model for Ultra-Low Velocity Zones (anomalous region on the mantle side of the core-mantle boundary). Furthermore we study the behaviour of Ni, Co, and Fe in these melts, and asses their spin-crossover dependencies on their concentration, pressure, temperature, and the degree of polymerization of the silicate melts. We show that a decrease in the average spin can be correlated with the previously observed kink in the partitioning coefficient of Ni and Co. We investigate the melt structure of all the compositions studied as a function of pressure. Our results provide new insight into the coordination of major and trace elements in silicate melts with different degrees of polymerization. We interpret the anomalous Ni-O coordination trend with pressure as the result of the spin state change. The effect of silicate melt polymerization on the partitioning of Co, Ni, and W between a metal and silicate melt, is investigated at isobaric and isothermic conditions using multi-anvil experiments. We have performed FPMD simulations of melts with similar degrees of polymerization as the experiments in order to explain the increasing lithophile character of W with the decrease in polymerization of the silicate melt. We propose a structural explanation for tungsten's apparent increased affinity for depolymerized silicate melts.
Download or read book Silicate Melts written by Sharon Webb and published by Springer. This book was released on 1997-07-17 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the experimental determination of the physical properties of silicate melts and magmas close to glass transition. Abundant new data are presented. The same type of measurement is performed on a range of melts to test the effect of composition on physical properties; and a range of different techniques are used to determine the same physical properties to illustrate the relationships between the relaxation of the melt structure and the relaxation of its physical properties. This book is of interest to experimental researchers in the discussion of data obtained from both a materials science and a geoscientific point of view.
Download or read book An Experimental Determination of Rare Earth Partition Coefficients Between a Chloride containing Aqueous Phase and Silicate Melts written by Ronald Thomas Flynn and published by . This book was released on 1977 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quartz Deposits Mineralogy and Analytics written by Jens Götze and published by Springer Science & Business Media. This book was released on 2012-04-23 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book will include contributions of the state of the art of quartz raw materials (deposits and properties) and their analytics. The chapters are presented by leading scientists in the quartz field. The presentations cover the main interrelations between genesis of quartz - formation of specific properties - analytics - industrial applications of SiO2 raw materials.
Download or read book Earth and Mineral Sciences written by and published by . This book was released on 1987 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deep Carbon written by Beth N. Orcutt and published by Cambridge University Press. This book was released on 2019-10-17 with total page 687 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive guide to carbon inside Earth - its quantities, movements, forms, origins, changes over time and impact on planetary processes. This title is also available as Open Access on Cambridge Core.
Download or read book Orogenic Andesites and Plate Tectonics written by J. B. Gill and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: Students of a phenomenon as common but complex as andesite genesis often are overwhelmed by, or overlook, the volume and diversity of relevant information. Thus there is need for periodic overview even in the absence of a dramatic breakthrough which "solves the andesite problem" and even though new ideas and data keep the issues in a state of flux. Thus I have summarized the subject through mid·1980 from my perspective to help clarify the long-standing problem and to identify profitable areas for future research. Overviews are more easily justified than achieved and there are fundamental differences of opinion concerning how to go about them. It is professionally dangerous and therefore uncom mon for single authors, especially those under 35 such as I, to summarize a broad, active field of science in book-length thor oughness. Review articles in journals, multi-authored books, or symposia proceedings appear instead. The single-authored approach is intimidating in scale and can result in loss of thoroughness or authority on individual topics. The alternatives lack scope or integration or both.
Download or read book Carbon in Earth s Interior written by Craig E. Manning and published by John Wiley & Sons. This book was released on 2020-04-03 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon in Earth's fluid envelopes - the atmosphere, biosphere, and hydrosphere, plays a fundamental role in our planet's climate system and a central role in biology, the environment, and the economy of earth system. The source and original quantity of carbon in our planet is uncertain, as are the identities and relative importance of early chemical processes associated with planetary differentiation. Numerous lines of evidence point to the early and continuing exchange of substantial carbon between Earth's surface and its interior, including diamonds, carbon-rich mantle-derived magmas, carbonate rocks in subduction zones and springs carrying deeply sourced carbon-bearing gases. Thus, there is little doubt that a substantial amount of carbon resides in our planet's interior. Yet, while we know it must be present, carbon's forms, transformations and movements at conditions relevant to the interiors of Earth and other planets remain uncertain and untapped. Volume highlights include: - Reviews key, general topics, such as carbonate minerals, the deep carbon cycle, and carbon in magmas or fluids - Describes new results at the frontiers of the field with presenting results on carbon in minerals, melts, and fluids at extreme conditions of planetary interiors - Brings together emerging insights into carbon's forms, transformations and movements through study of the dynamics, structure, stability and reactivity of carbon-based natural materials - Reviews emerging new insights into the properties of allied substances that carry carbon, into the rates of chemical and physical transformations, and into the complex interactions between moving fluids, magmas, and rocks to the interiors of Earth and other planets - Spans the various chemical redox states of carbon, from reduced hydrocarbons to zero-valent diamond and graphite to oxidized CO2 and carbonates - Captures and synthesizes the exciting results of recent, focused efforts in an emerging scientific discipline - Reports advances over the last decade that have led to a major leap forward in our understanding of carbon science - Compiles the range of methods that can be tapped tap from the deep carbon community, which includes experimentalists, first principles theorists, thermodynamic modelers and geodynamicists - Represents a reference point for future deep carbon science research Carbon in Planetary Interiors will be a valuable resource for researchers and students who study the Earth's interior. The topics of this volume are interdisciplinary, and therefore will be useful to professionals from a wide variety of fields in the Earth Sciences, such as mineral physics, petrology, geochemistry, experimentalists, first principles theorists, thermodynamics, material science, chemistry, geophysics and geodynamics.
Download or read book Water in Nominally Anhydrous Minerals written by Hans Keppler and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 62 of Reviews in Mineralogy and Geochemistry reviews the recent research in the geochemistry and mineral physics of hydrogen in the principal mineral phases of the Earth's crust and mantle. Contents: Analytical Methods for Measuring Water in Nominally Anhydrous Minerals The Structure of Hydrous Species in Nominally Anhydrous Minerals: Information from Polarized IR Spectroscopy Structural Studies of OH in Nominally Anhydrous Minerals Using NMR Atomistic Models of OH Defects in Nominally Anhydrous Minerals Hydrogen in High Pressure Silicate and Oxide Mineral Structures Water in Nominally Anhydrous Crustal Minerals: Speciation, Concentration, and Geologic Significance Water in Natural Mantle Minerals I: Pyroxenes Water in Natural Mantle Minerals II: Olivine, Garnet and Accessory Minerals Thermodynamics of Water Solubility and Partitioning The Partitioning of Water Between Nominally Anhydrous Minerals and Silicate Melts The Stability of Hydrous Mantle Phases Hydrous Phases and Water Transport in the Subducting Slab Diffusion of Hydrogen in Minerals Effect of Water on the Equation of State of Nominally Anhydrous Minerals Remote Sensing of Hydrogen in Earth's Mantle
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 Interactions Between Aqueous Fluids and Silicate Melts written by Manuela Borchert and published by . This book was released on 2009 with total page 113 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.
