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  • 1
    Monograph available for loan
    Monograph available for loan
    Washington, D.C. : Mineralogical Society of America
    Associated volumes
    Call number: 11/M 04.0253
    In: Reviews in mineralogy & geochemistry
    Description / Table of Contents: Until only a few years ago, I would never have imagined that a volume on the stable isotope geochemistry of elements like Mg, Fe or Cu would be written. In fact, a comic book of blank pages entitled The Stable Isotope Geochemistry of Fluorine would have been a more likely prospect. In volume 16 of this series, published in 1986, I wrote: Isotopic variations have been looked for but not found for heavy elements like Cu, Sn, and Fe .... Natural variations in isotopic ratios of terrestrial materials have been reported for other light elements like Mg and K, but such variations usually turn out to be laboratory artifacts. I am about ready to eat those words. We have known for many years that large isotopic fractionations of heavy elements like Pb develop in the source regions of TIMS machines. Nonetheless, most of us held fast to the conventional wisdom that no significant mass-dependent isotopic fractionations were likely to occur in natural or laboratory systems for elements that are either heavy or engaged in bonds with a dominant ionic character. With the relatively recent appearance of new instrumentation like MC-ICP-MS and heroic methods development in TIMS analyses, it became possible to make very precise measurements of the isotopic ratios of some of these non-traditional elements, particularly if they comprise three or more isotopes. It was eminently reasonable to reexamine these systems in this new light. Perhaps atomic weights could be refined, or maybe there were some unexpected isotopic variations to discover. There were around the turn of the present century, reports began appearing of biological fractionations of about 2-3 per mil for heavy elements like Fe and Cr and attempts were made to determine the magnitude of equilibrium isotope effects in these systems, both by experiment and semi-empirical calculations. Interest emerged in applying these effects to the study of environmental problems. Even the most recalcitrant skeptic now accepts the fact that measurable and meaningful variations in the isotopic ratios of heavy elements occur as a result of chemical, biological and physical processes. Most of the work discussed in this volume was published after the year 2000 and thus the chapters are more like progress reports rather than reviews. Skepticism now focuses on whether isotopic variations as small as 0.1 per mil are indeed as meaningful as some think, and the fact that measured isotopic fractionations of these non-traditional elements are frequently much smaller than predicted from theoretical considerations. In fact the large fractionations suggested by the calculations provide much of the stimulus for working in this discipline. Clearly some carefully designed experiments could shed light on some of the ambiguity. My optimism for the future of this burgeoning new field remains high because it is in very good hands indeed. Approximately three-quarters of the elements in the Periodic Table have two or more isotopes. RiM 16 and RiMG 43 were devoted to H, C, 0, and S isotope variations, and B isotope variations were discussed in RiM 33. The importance of these elements to geochemistry may be illustrated by a GeoRef search of 0 isotope publications, which yields over 25,000 papers, theses, and abstracts spanning over five decades. Isotopic variations of the remaining 56 elements that have two or more isotopes, however, remains relatively little explored, but is gaining rapid attention, in part driven by advances in analytical instrumentation in the last 5-10 years. Our goal for this volume was to bring together a summary of the isotope geochemistry of non-traditional stable isotope systems as is known through 2003 for those elements that have been studied in some detail, and which have a variety of geochemical properties. In addition, recognizing that many of these elements are of interest to workers who are outside the traditional stable isotope fields, we felt it was important to include discussions on the broad isotopic variations that occur in the solar system, theoretical approaches to calculating isotopic fractionations, and the variety of analytical methods that are in use. We hope, therefore, that this volume proves to be useful to not only the isotope specialist, but to others who are interested in the contributions that these non-traditional stable isotopes may make toward understanding geochemical and biological cycles.
    Type of Medium: Monograph available for loan
    Pages: XV, 454 S. , Ill., graph. Darst
    ISBN: 0-939950-67-7 , 978-0-939950-67-6
    ISSN: 1529-6466
    Series Statement: Reviews in mineralogy & geochemistry 55
    Classification:
    Geochemistry
    Note: Chapter 1. Overview and General Concepts by Clark M. Johnson, Brian L. Beard and Francis Albarede, p. 1 - 24 Chapter 2. An Overview of Isotopic Anomalies in Extraterrestrial Materials and Their Nucleosynthetic Heritage by Jean Louis Birck, p. 25 - 64 Chapter 3. Applying Stable Isotope Fractionation Theory to New Systems by Edwin A. Schauble, p. 65 - 112 Chapter 4. Analytical Methods for Non-Traditional Isotopes by Francis AlbarÀde and Brian L. Beard, p. 113 - 152 Chapter 5. Developments in the Understanding and Application of Lithium Isotopes in the Earth and Planetary Sciences by Paul B. Tomascak, p. 153 - 196 Chapter 6. The Isotope Geochemistry and Cosmochemistry of Magnesium by Edward D. Young and Albert Galy, p. 197 - 230 Chapter 7. The Stable-Chlorine Isotope Compositions of Natural and Anthropogenic Materials by Michael A. Stewart and Arthur J. Spivack, p. 231 - 254 Chapter 8. Calcium Isotopic Variations Produced by Biological, Kinetic, Radiogenic and Nucleosynthetic Processes by Donald J. DePaolo, p. 255 - 288 Chapter 9. Mass-Dependent Fractionation of Selenium and Chromium Isotopes in Low-Temperature Environments by by Thomas M. Johnson and Thomas D. Bullen, p. 289 - 318 Chapter 10A. Fe Isotope Variations in the Modern and Ancient Earth and Other Planetary Bodies by Brian L. Beard and Clark M. Johnson, p. 319 - 358 Chapter 10B. Isotopic Constraints on Biogeochemical Cycling of Fe by Clark M. Johnson, Brian L. Beard, Eric E. Roden, Dianne K. Newman and Kenneth H. Nealson, p. 359 - 408 Chapter 11. The stable isotope geochemistry of copper and zinc by Francis Albarede, p. 409 - 428 Chapter 12. Molybdenum Stable Isotopes: Observations, Interpretations and Directions by Ariel D. Anbar, p. 429 - 454
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  • 2
    ISSN: 1437-3262
    Keywords: Bohemian Massif ; Eclogites Geochronology ; Sr and Nd isotopes ; Mariánské Lázně Complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Mariánské Lázně complex (MLC) is located in the Bohemian Massif along the north-western margin of the Teplá-Barrandian microplate and consists of metagabbro, amphibolite and eclogite, with subordinate amounts of serpentinite, felsic gneiss and calcsilicate rocks. The MLC is interpreted as a metaophiolite complex that marks the suture zone between the Saxothuringian rocks to the north-west and the Teplá-Barrandian microplate to the south-east. Sm-Nd geochronology of garnet-omphacite pairs from two eclogite samples yields ages of 377±7, and 367±4 Ma. Samples of eclogite and amphibolite do not define a whole rock Sm-Nd isochron, even though there is a large range in Sm/Nd ratio, implying that the suite of samples may not be cogenetic. Eclogites do not have correlated ɛ Nd values and initial 87Sr/86Sr ratios. Five of the eight eclogite samples have high ɛ Nd values (+10.2 to +7.1) consistent with derivation from a MORB-like source, but variable 87Sr/86Sr ratios (0.7033 to 0.7059) which probably reflect hydrothermal seawater alteration. Three other eclogite samples have lower ɛNd values (+ 5.4 to −0.8) and widely variable 87Sr/86Sr ratios (0.7033 to 0.7096). Such low ɛNd values are inconsistent with derivation from a MORB, source and may reflect a subduction or oceanic island basalt component in their source. The MLC is an important petrotectonic element in the Bohemian Massif, providing evidence for Cambro-Ordovician formation of oceanic crust and interaction with seawater, Late Devonian (Frasnian-Famennian) high- and medium-pressure metamorphism related to closure of a Saxothuringian ocean basin, Early Carboniferous (Viséan) thrusting of the Teplá terrane over Saxothuringian rocks and Late Viséan extension.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0016-7835
    Keywords: Key words Bohemian Massif ; Eclogites ; Geochronology ; Sr and Nd isotopes ; Mariánské Lázně Complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The Mariánské Lázně complex (MLC) is located in the Bohemian Massif along the north-western margin of the Teplá-Barrandian microplate and consists of metagabbro, amphibolite and eclogite, with subordinate amounts of serpentinite, felsic gneiss and calc-silicate rocks. The MLC is interpreted as a metaophiolite complex that marks the suture zone between the Saxothuringian rocks to the north-west and the Teplá-Barrandian microplate to the south-east. Sm-Nd geochronology of garnet-omphacite pairs from two eclogite samples yields ages of 377±7, and 367±4 Ma. Samples of eclogite and amphibolite do not define a whole rock Sm-Nd isochron, even though there is a large range in Sm/Nd ratio, implying that the suite of samples may not be cogenetic. Eclogites do not have correlated εNd values and initial 87Sr/86Sr ratios. Five of the eight eclogite samples have high εNd values (+10.2 to +7.1) consistent with derivation from a MORB-like source, but variable 87Sr/86Sr ratios (0.7033 to 0.7059) which probably reflect hydrothermal seawater alteration. Three other eclogite samples have lower εNd values (+5.4 to –0.8) and widely variable 87Sr/86Sr ratios (0.7033 to 0.7096). Such low εNd values are inconsistent with derivation from a MORB source and may reflect a subduction or oceanic island basalt component in their source. The MLC is an important petrotectonic element in the Bohemian Massif, providing evidence for Cambro-Ordovician formation of oceanic crust and interaction with seawater, Late Devonian (Frasnian-Famennian) high- and medium-pressure metamorphism related to closure of a Saxothuringian ocean basin, Early Carboniferous (Viséan) thrusting of the Teplá terrane over Saxothuringian rocks and Late Viséan extension.
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 362 (1993), S. 441-444 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It is well established that 143Nd/144Nd and 176Hf/177Hf ratios of modern ocean-island basalts (OIB) are well correlated, reflecting correlated variations in Sm/Nd and Lu-Hf parent-daughter ratios that must have been established several billion years ago to produce systematic variations in ...
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  • 5
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract High-temperature (HT), Group A eclogites from three localities in the Moldanubian Zone of the Bohemian Massif are interpreted to have formed in the mantle and to have been transported into the crust by their enclosing garnet peridotites during Variscan orogenesis. Garnet and omphacite are compositionally zoned and contain homogeneous cores and retrograde rims. Cores of minerals yield minimum temperatures and pressures of 850 to 985°C and 16.0 to 22.5 kb, based on Fe−Mg exchange between garnet and clinopyroxene and the jadeite content of clinopyroxene. Sugh high temperatures indicate equilibration in, and derivation from, the upper mantle. Trace element compositions, including the REEs, high MgO contents, and high Mg numbers suggest that the rocks formed by high pressure accumulation of garnet and clinopyroxene and variable amounts of trapped melt. Sm-Nd ages determined on four garnet-clinopyroxene pairs from the three localities are 377±20, 342±9, 336±16, and 323±7 Ma. ɛ Nd and initial 87Sr/86Sr are negatively correlated, varying from +6.7 to -0.1 and 0.7027 to 0.7057, respectively. Field, compositional, and isotopic data indicate that the eclogites were derived from heterogeneous mantle that included depleted and enriched compositions; this heterogeneity may have resulted from subduction processes that occurred prior to the late Variscan collision of Gondwana and Baltica.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 133 (1998), S. 402-417 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract High-K mafic alkalic lavas (5.4 to 3.2 wt% K2O) from Deep Springs Valley, California define good correlations of increasing incompatible element (e.g., Sr, Zr, Ba, LREE) and compatible element contents (e.g., Ni, Cr) with increasing MgO. Strontium and Nd isotope compositions are also correlated with MgO; 87Sr/86Sr ratios decrease and ɛNd values increase with decreasing MgO. The Sr and Nd isotope compositions of these lavas are extreme compared to most other continental and oceanic rocks; 87Sr/86Sr ratios range from 0.7121 to 0.7105 and ɛNd values range from −16.9 to −15.4. Lead isotope ratios are relatively constant, 206Pb/204Pb ∼17.2, 207Pb/204Pb ∼15.5, and 208Pb/204Pb ∼38.6. Depleted mantle model ages calculated using Sr and Nd isotopes imply that the reservoir these lavas were derived from has been distinct from the depleted mantle reservoir since the early Proterozoic. The Sr-Nd-Pb isotope variations of the Deep Springs Valley lavas are unique because they do not plot along either the EM I or EM II arrays. For example, most basalts that have low ɛNd values and unradiogenic 206Pb/204Pb ratios have relatively low 87Sr/86Sr ratios (the EM I array), whereas basalts with low ɛNd values and high 87Sr/86Sr ratios have radiogenic 206Pb/204Pb ratios (the EM II array). High-K lavas from Deep Springs Valley have EM II-like Sr and Nd isotope compositions, but EM I-like Pb isotope compositions. A simple method for producing the range of isotopic and major- and trace-element variations in the Deep Springs Valley lavas is by two-component mixing between this unusual K-rich mantle source and a more typical depleted mantle basalt. We favor passage of MORB-like magmas that partially fused and were contaminated by potassic magmas derived from melting high-K mantle veins that were stored in the lithospheric mantle. The origin of the anomalously high 87Sr/86Sr and 208Pb/204Pb ratios and low ɛNd values and 206Pb/204Pb ratios requires addition of an old component with high Rb/Sr and Th/Pb ratios but low Sm/Nd and U/Pb ratios into the mantle source region from which these basalts were derived. This old component may be sediments that were introduced into the mantle, either during Proterozoic subduction, or by foundering of Proterozoic age crust into the mantle at some time prior to eruption of the lavas.
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  • 7
    Publication Date: 2015-06-24
    Description: Banded iron formations (BIFs) record a time of extensive Fe deposition in the Precambrian oceans, but the sources and pathways for metals in BIFs remain controversial. Here, we present Fe- and Nd-isotope data that indicate two sources of Fe for the large BIF units deposited 2.5 billion y ago. High-εNd and -δ56Fe signatures in some BIF samples record a hydrothermal component, but correlated decreases in εNd- and δ56Fe values reflect contributions from a continental component. The continental Fe source is best explained by Fe mobilization on the continental margin by microbial dissimilatory iron reduction (DIR) and confirms for the first time, to our knowledge, a microbially driven Fe shuttle for the largest BIFs on Earth. Detailed sampling at various scales shows that the proportions of hydrothermal and continental Fe sources were invariant over periods of 100–103 y, indicating that there was no seasonal control, although Fe sources varied on longer timescales of 105–106 y, suggesting a control by marine basin circulation. These results show that Fe sources and pathways for BIFs reflect the interplay between abiologic (hydrothermal) and biologic processes, where the latter reflects DIR that operated on a basin-wide scale in the Archean.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 8
    Publication Date: 2019-04-15
    Description: The causal effects among uplift, climate, and continental weathering cannot be fully addressed using presently available geochemical proxies. However, stable potassium (K) isotopes can potentially overcome the limitations of existing isotopic proxies. Here we report on a systematic investigation of K isotopes in dissolved load and sediments from major rivers and their tributaries in China, which have drainage basins with varied climate, lithology, and topography. Our results show that during silicate weathering, heavy K isotopes are preferentially partitioned into aqueous solutions. Moreover, δ41K values of riverine dissolved load vary remarkably and correlate negatively with the chemical weathering intensity of the drainage basin. This correlation allows an estimate of the average K isotope composition of global riverine runoff (δ41K = −0.22‰), as well as modeling of the global K cycle based on mass balance calculations. Modeling incorporating K isotope mass balance better constrains estimated K fluxes for modern global K cycling, and the results show that the δ41K value of seawater is sensitive to continental weathering intensity changes. Thus, it is possible to use the δ41K record of paleo-seawater to infer continental weathering intensity through Earth’s history.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 9
    Publication Date: 2009-02-15
    Print ISSN: 0013-936X
    Electronic ISSN: 1520-5851
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
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  • 10
    Publication Date: 2011-03-01
    Print ISSN: 0013-936X
    Electronic ISSN: 1520-5851
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
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