Download or read book Non mass Dependent Fractionation of Sulfur and Oxygen Isotopes During UV Photolysis of SO2 written by Aranh Pen and published by . This book was released on 2009 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mass independent Sulfur Isotope Fractionation During Photochemistry of Sulfur Dioxide written by Andrew Richard Whitehill and published by . This book was released on 2015 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass-independent sulfur isotope signatures are observed in Archean and early Paleoproterozoic sedimentary sulfate and sulfide minerals, and provide the most robust constraints on early atmospheric oxygen levels. Smaller mass-independent sulfur isotope anomalies are observed in ice cores and interpreted as a tracer of stratospheric volcanic loading. Photochemistry of sulfur dioxide (SO2) has been implicated as a possible source of the mass-independent sulfur isotope signatures in both the modern stratosphere and on the early earth. However, the mechanisms responsible for the production of mass-independent sulfur isotope fractionation remain poorly constrained. This thesis investigates the multiple sulfur isotope systematics during photochemical reactions of sulfur dioxide as a function of a variety of experimental conditions. Two absorption regions of SO2 are tested - photolysis in the 190 to 220 nm region and photoexcitation in the 250 to 350 nm region. Experimental conditions modified include temperature, SO2 pressure, bath gas pressure, and addition of reactive gases (C2 H2, 02 and CH4). Results of photochemical experiments are compared with isotope systematics predicted from isotopologue-specific absorption cross-sections to identify potential mechanisms for the production of mass-independent fractionation during photochemical reactions. Strong similarity between the isotope systematics of SO2 photolysis and ice core data suggest that SO2 photolysis is responsible for the production of mass-independent sulfur isotope effects in the modern stratosphere. In contrast, significant discrepancies between the isotope signatures from SO2 photochemistry and those in the Archean record suggest that, although SO2 photolysis was likely an important process in the Archean atmosphere, an additional reaction likely contributes to the mass-independent sulfur isotope signatures preserved in the Archean rock record.
Download or read book Isotope Effects In Chemistry and Biology written by Amnon Kohen and published by CRC Press. This book was released on 2005-11-01 with total page 1092 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of isotope effects has expanded exponentially in the last decade, and researchers are finding isotopes increasingly useful in their studies. Bringing literature on the subject up to date, Isotope Effects in Chemistry and Biology covers current principles, methods, and a broad range of applications of isotope effects in the physical, biolo
Download or read book Isotope Geochemistry written by William M. White and published by John Wiley & Sons. This book was released on 2015-01-27 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to radiogenic and stable isotope geochemistry. Beginning with a brief overview of nuclear physics and nuclear origins, it then reviews radioactive decay schemes and their use in geochronology. A following chapter covers the closely related techniques such as fission-track and carbon-14 dating. Subsequent chapters cover nucleosynthetic anomalies in meteorites and early solar system chronology and the use of radiogenic isotopes in understanding the evolution of the Earth’s mantle, crust, and oceans. Attention then turns to stable isotopes and after reviewing the basic principles involved, the book explores their use in topics as diverse as mantle evolution, archeology and paleontology, ore formation, and, particularly, paleoclimatology. A following chapter explores recent developments including unconventional stable isotopes, mass-independent fractionation, and isotopic ‘clumping’. The final chapter reviews the isotopic variation in the noble gases, which result from both radioactive decay and chemical fractionations.
Download or read book Mechanisms of Sulfur Isotope Fractionation During Thermochemical Sulfate Reduction by Amino Acids written by Andrew Chorney and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The understanding of the evolution of the earth's early atmosphere has largely been based on the behavior of the multiple isotopes of sulfur. However experiments designed to mimic fractionation in both an oxygen poor atmosphere through SO2 photolysis and a presumably oxygen rich atmosphere though thermochemical sulfate reduction (TSR) have thus far been unable to confirm a mechanism capable of creating the mass independent fractionation of sulfur (MIF-S) signatures observed in Archean age rocks. This has created much controversy in how the MIF-S record is used to determine Archean environments. However large amounts of geochemical evidence suggest at least appreciable amounts of oxygen in the atmosphere and ocean at different stages through the Archean. This has motivated us to further explore TSR as a source of MIF-S through a rigorous investigation of how chemical speciation, experimental conditions, time, and rate effect sulfur isotope fractionation. Our results show the importance of initial sulfur redox state and chemistry, temperature, and organic reductant type in creating characteristic mass dependent and independent fractionations. Including previous TSR results (Watanabe et. al., 2009 and Oduro et. al., 2011) we report increased [delta]34S and [delta]36S fractionation in TSR products to 15.50[per mille symbol] and 1.5[per mille symbol] respectively and increased [delta]33S range from -.22 to 2.30[per mille symbol] in H2S largely through the use of mixtures of glycine and alanine. In sulfate we observe [delta]34S fractionation between 0.00 and 7.85[per mille symbol] and [delta]33S fractionation between -.15[per mille symbol] and 0.0[per mille symbol]. By quantifying fractionation amongst different sulfur bearing products produced during experiments and collected at experiment conclusions in addition to characterizing the effects due to various experimental conditions we are also able describe a schematic framework for the isotope effects during various steps of TSR. Fractionation from the magnetic isotope effect (MIE), the vibrational energy discontinuity effect (VEDE), first described for heterogeneous reactions by Lasaga et. al, 2008, and normal stable isotope mass dependently driven kinetic isotope effects (KIE) are utilized in this schematic to describe the experimental results. The MIE and VEDE are responsible for the MIF-S signatures observed in organic polysulfides and H2S at high temperatures. Additionally the effects of these mechanisms are greatly influenced by amino acid type, specifically in experiments that use a mixture of glycine and alanine. The VEDE and KIE are responsible for [delta]34S fractionation with the overall effect of producing sulfide depleted in 34S at lower temperatures. The interplay of these mechanisms is responsible for [delta]33S and [delta]34S trends observed in sulfides and sulfate samples. Based on this proposed schematic for sulfur isotope fractionation during TSR major trends and features in the Archean [delta]33S vs. [delta]34S and [delta]36S vs. [delta]33S record can be interpreted. Our results confirm that MIF-S signatures observed in natural samples are a product of depositional environment and possibly reflect characteristics of reactions specific to sedimentary basin conditions and early earth's tectonic regime.
Download or read book Mass Independent Isotopic Fractionation in Solid Phase written by Xianping Xu and published by . This book was released on 1998 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geochemistry written by Francis Albarède and published by Cambridge University Press. This book was released on 2009-06-25 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introducing the essentials of modern geochemistry for students across the Earth and environmental sciences, this new edition emphasises the general principles of this central discipline. Focusing on inorganic chemistry, Francis Albarède's refreshing approach is brought to topics that range from measuring geological time to the understanding of climate change. The author leads the student through the necessary mathematics to understand the quantitative aspects of the subject in an easily understandable manner. The early chapters cover the principles and methods of physics and chemistry that underlie geochemistry, to build the students' understanding of concepts such as isotopes, fractionation, and mixing. These are then applied across many of the environments on Earth, including the solid Earth, rivers, and climate, and then extended to processes on other planets. Three new chapters have been added – on stable isotopes, biogeochemistry, and environmental geochemistry. End-of-chapter student exercises, with solutions available online, are also included.
Download or read book Cosmochemistry written by Harry McSween, Jr and published by Cambridge University Press. This book was released on 2022-03-03 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thoroughly updated to include exciting discoveries from spacecraft missions and laboratory analyses, as well as new teaching resources.
Download or read book Astrobiology written by Charles S. Cockell and published by John Wiley & Sons. This book was released on 2015-09-29 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrobiology is an interdisciplinary field that asks profound scientific questions. How did life originate on the Earth? How has life persisted on the Earth for over three billion years? Is there life elsewhere in the Universe? What is the future of life on Earth? Astrobiology: Understanding Life in the Universe is an introductory text which explores the structure of living things, the formation of the elements for life in the Universe, the biological and geological history of the Earth and the habitability of other planets in our own Solar System and beyond. The book is designed to convey some of the major conceptual foundations in astrobiology that cut across a diversity of traditional fields including chemistry, biology, geosciences, physics and astronomy. It can be used to complement existing courses in these fields or as a stand-alone text for astrobiology courses. Readership: Undergraduates studying for degrees in earth or life sciences, physics, astronomy and related disciplines, as well as anyone with an interest in grasping some of the major concepts and ideas in astrobiology.
Download or read book Introduction to Geochemistry written by Kula C. Misra and published by John Wiley & Sons. This book was released on 2012-05-21 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended to serve as a text for an introductory course in geochemistry for undergraduate/graduate students with at least an elementary–level background in earth sciences, chemistry, and mathematics. The text, containing 83 tables and 181 figures, covers a wide variety of topics — ranging from atomic structure to chemical and isotopic equilibria to modern biogeochemical cycles — which are divided into four interrelated parts: Crystal Chemistry; Chemical Reactions (and biochemical reactions involving bacteria); Isotope Geochemistry (radiogenic and stable isotopes); and The Earth Supersystem, which includes discussions pertinent to the evolution of the solid Earth, the atmosphere, and the hydrosphere. In keeping with the modern trend in the field of geochemistry, the book emphasizes computational techniques by developing appropriate mathematical relations, solving a variety of problems to illustrate application of the mathematical relations, and leaving a set of questions at the end of each chapter to be solved by students. However, so as not to interrupt the flow of the text, involved chemical concepts and mathematical derivations are separated in the form of boxes. Supplementary materials are packaged into ten appendixes that include a standard–state (298.15 K, 1 bar) thermodynamic data table and a listing of answers to selected chapter–end questions. Additional resources for this book can be found at: www.wiley.com/go/misra/geochemistry.
Download or read book Isotope Geochemistry written by Heinrich D Holland and published by Academic Press. This book was released on 2010-09-27 with total page 750 pages. Available in PDF, EPUB and Kindle. Book excerpt: After the discovery that elements were commonly composed of isotopes, there developed a range of studies of the variability of isotopic compositions in Earth materials, which was able to add to our understanding of Earth processes and history. This collection of chapters from the Treatise on Geochemistry describes the range of isotopic studies. The chapters are grouped into the following categories: light stable isotopes, radiogenic tracers, noble gases and radioactive tracers. The first three groups depend on mass spectrometric measurements. The section on radioactive tracers employs both radioactive counting techniques and the newly developed accelerator mass spectrometric techniques. Comprehensive, interdisciplinary and authoritative content selected by leading subject experts Robust illustrations, figures and tables Affordably priced sampling of content from the full Treatise on Geochemistry
Download or read book A Mass Independent Sulfur Isotope Effect in the Non Thermal Formation of S 2F 10 written by Swroop K. Bains-Sahota and published by . This book was released on 1988 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EPSL Frontiers written by A. Halliday and published by Elsevier. This book was released on 2005-02-09 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new section of short reviews called 'Frontiers' was introduced within the Elsevier journal Earth and Planetary Science Letters (EPSL) in 2002 under the Editorship of Alex Halliday from ETH Zurich, Switzerland. These high profile Frontiers articles are written by leading experts and published as the opening pages to regular issues of EPSL. The reason for this development is that the Editors of EPSL believe there is an important niche to be filled with fast communications that bring the scientific community up-to-speed on interesting new areas of science. Frontiers articles are therefore specifically intended for the non-specialist earth and planetary science readership. In order to reach a broader readership, those without subscriptions to the journal, Frontiers articles will now also be published in a new book series, the EPSL Frontiers series. Volume 1 will contain all 2002 and 2003 Frontiers articles. Future volumes will contain one year of articles each.
Download or read book The Origin and Nature of Life on Earth written by Eric Smith and published by Cambridge University Press. This book was released on 2016-03-31 with total page 703 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uniting the foundations of physics and biology, this groundbreaking multidisciplinary and integrative book explores life as a planetary process.
Download or read book Astrobiology written by and published by . This book was released on 2002 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Geobiology written by Andrew H. Knoll and published by John Wiley & Sons. This book was released on 2012-03-30 with total page 876 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2012 PROSE Award, Earth Science: Honorable Mention For more than fifty years scientists have been concerned with the interrelationships of Earth and life. Over the past decade, however, geobiology, the name given to this interdisciplinary endeavour, has emerged as an exciting and rapidly expanding field, fuelled by advances in molecular phylogeny, a new microbial ecology made possible by the molecular revolution, increasingly sophisticated new techniques for imaging and determining chemical compositions of solids on nanometer scales, the development of non-traditional stable isotope analyses, Earth systems science and Earth system history, and accelerating exploration of other planets within and beyond our solar system. Geobiology has many faces: there is the microbial weathering of minerals, bacterial and skeletal biomineralization, the roles of autotrophic and heterotrophic metabolisms in elemental cycling, the redox history in the oceans and its relationship to evolution and the origin of life itself.. This book is the first to set out a coherent set of principles that underpin geobiology, and will act as a foundational text that will speed the dissemination of those principles. The chapters have been carefully chosen to provide intellectually rich but concise summaries of key topics, and each has been written by one or more of the leading scientists in that field.. Fundamentals of Geobiology is aimed at advanced undergraduates and graduates in the Earth and biological sciences, and to the growing number of scientists worldwide who have an interest in this burgeoning new discipline. Additional resources for this book can be found at: http://www.wiley.com/go/knoll/geobiology.
Download or read book Volcanic Plumes written by Pasquale Sellitto and published by MDPI. This book was released on 2019-03-21 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volcanoes release plumes of gas and ash to the atmosphere during episodes of passive and explosive behavior. These ejecta have important implications for the chemistry and composition of the troposphere and stratosphere, with the capacity to alter Earth's radiation budget and climate system over a range of temporal and spatial scales. Volcanogenic sulphur dioxide reacts to form sulphate aerosols, which increase global albedo, e.g., by reducing surface temperatures, in addition to perturbing the formation processes and optical properties of clouds. Released halogen species can also deplete stratospheric and tropospheric ozone. Volcanic degassing, furthermore, played a key role in the formation of Earth’s atmosphere, and volcanic plumes can affect air quality, pose hazards to aviation and human health, as well as damage ecosystems. The chemical compositions and emission rates of volcanic plumes are also monitored via a range of direct-sampling and remote-sensing instrumentation, in order to gain insights into subterranean processes, in the respect of the magmatic bodies these volatiles exsolve from. Given the significant role these gases play in driving volcanic activity, e.g., via pressurisation, the study of volcanic plumes is proving to be an increasingly fruitful means of improving our understanding of volcanic systems, potentially in concert with observations from geophysics and contributions from fluid dynamical modelling of conduit dynamics. This Special Issue is aimed at presenting the state of the art of the multidisciplinary science concerning all aspects of volcanic plumes, of relevance to the volcanology, climatology, atmospheric science, and remote sensing communities.
