Download or read book Geochemistry of Trace Metals Associated with Sedimentary Pyrite from Anoxic Marine Environments written by Miguel Angel Huerta-Diaz and published by . This book was released on 1989 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Pyrite Trace Element Paleo Ocean Chemistry Proxy written by Daniel D. Gregory and published by Cambridge University Press. This book was released on 2020-12-24 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of the trace element content of sedimentary pyrite as a proxy for the trace element composition of past oceans has recently emerged. The pyrite proxy has several potential advantages over bulk sample analysis: preservation through metamorphism; little dilution during analysis (samples are ablated not dissolved, allowing for the less abundant elements commonly held in the sulfide fraction to be investigated as proxies); accurate measurement of several elements simultaneously; the ability to screen sediments for hydrothermal overprint; and the technique can give information regarding trace element availably at multiple stages of diagenesis. Because of these multiple strengths, the pyrite trace element proxy is a valuable potential addition to the paleo-ocean chemistry tool kit.
Download or read book Isotopic and Trace Metal Geochemistry of Calcite Gypsum and Pyrite as Proxies for Ancient Life and Environments written by Muammar Mansor and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Geoscientists reconstruct the past in order to understand the future. Minerals and associated geochemical (isotopic and trace metal) signatures act as tools for geoscientists to decipher past processes that led to Earths biogeochemical evolution. In this thesis, the geochemical signatures contained within calcite, gypsum and pyrite were characterized through a multidisciplinary approach involving genomics, field sampling, laboratory experiment and diagenetic modeling to understand the primary processes (abiotic and biotic) that led to specific geochemical signatures. These signatures are then interpreted as either biosignatures or as environmental indicators for the ancient Earth.Chapter 2 focuses on the unusual calcite (CaCO3) inclusions precipitated intracellularly within giant bacteria called Achromatium, which have the potential to be used as biosignatures. Single-cell genomics were utilized to shed light on the bacterias metabolisms and genetic machinery in forming intracellular calcite. Two potential functions were proposed for this unusual metabolism. First, calcite inclusions may have been deposited as ballasts to anchor the cells from being swept away by water flow. Second, intracellular calcite precipitation may be a novel way to generate free protons and ATP to sustain life. Limitations in current techniques hamper geochemical characterizations of the calcite inclusions; nonetheless, our progress in understanding Achromatium have paved the way for culture-based, omic or in silico modeling techniques that will be useful for interpreting specific signatures of microbial calcite.In Chapter 3, we will travel deep into the subsurface to look for gypsum (CaSO4.2H2O) minerals coated by slimes of sulfur-oxidizing microbes. The microbes consumed hydrogen sulfide to sulfate, imparting unique sulfur isotopic (34S) signatures in gypsum that are spatially recognizable at the cave room scale. Similar spatial isotopic patterns in subsurface systems may be utilized as biosignatures, subject to tighter constraints of physico-chemical diagenetic effects to gypsum deposits over million-year timescales.From Chapter 4 to 7, we will shift our attentions towards pyrite (FeS2) minerals. In Chapter 4, we will encounter submerged microbial ropes containing abundant pyrite (and its mineral polymorph, marcasite) that are potentially analogous to microbial biofilms in the anoxic early Earth. Combined with morphological, trace metals and Fe isotopic (56Fe) analysis, we suggest that the FeS2 minerals were formed through both Fe-oxides in the bedrock as well as dissolved Fe from the water, with significant catalysis induced by microbial sulfur cycling. Biofilm-associated FeS2 minerals are clearly different from sedimentary FeS2 in terms of morphology, mineralogy, trace metal and Fe isotopic compositions, rendering them potentially useful as a biosignature. Additionally, their differences suggest that care must be taken to interpreting geochemical signatures from Precambrian pyrite, which has traditionally been based solely on sedimentary pyrite.In Chapter 5 and 6, we will travel back to the laboratory and use defined experimental studies to constrain factors affecting the chemical signatures of pyrite. Chapter 5 is focused on molybdenum (Mo) content in pyrite as potential proxies for Mo content in ancient waters, with direct relevance towards testing the Mo scarcity hypothesis that impeded eukaryotic evolution during the Proterozoic. Experimental data show that the initial dissolved Mo concentrations are linearly correlated with Mo contents in pyrite. This relationship is validated for use in diagenetic pyrite under oxic to sub-oxic water column, but overestimates the Mo concentrations calculated from pyrite deposited under euxinic water columns. Correcting for these biases as much as possible, we determined that Proterozoic seawater had Mo concentrations between 1-50 nM and are typically higher than the 5 nM Mo limit for nitrogen fixation. Consequently, the Mo scarcity hypothesis cannot readily explain the lack of eukaryotic evolution in the middle Proterozoic.In Chapter 6, Fe isotopic analysis of laboratory-formed pyrite showed that the apparent fractionation associated with pyrite precipitation are affected by the relative rates of pyrite precipitation to isotopic exchange rate between FeS mineral and aqueous FeS at low temperatures ( 40C) and between aqueous FeS and pyrite at high temperatures ( 80C). In euxinic sediments where diagenetic pyrite formed, pyrite 56Fe may be used to constrain pyrite precipitation and burial rates, with implications to oxygen sinks particularly in the Precambrian.In Chapter 7, a diagenetic model is developed in order to characterize the effects of multiple pyrite precipitation pathways to pyrite 56Fe in marine sediments. Model outputs suggest that pyrite likely formed from at least two pathways: one mediated by aqueous Fe(II) and another mediated by surface-bound Fe(II). The models framework can easily explain the typical ~7 variation of individual pyrite grains within the same sediment. Additionally, bulk pyrite 56Fe that leans toward more positive values are characteristic of Fe(III)-dominated system while bulk pyrite 56Fe that leans toward more negative values are characteristic of Fe(II)-dominated system.
Download or read book Treatise on Estuarine and Coastal Science written by and published by Academic Press. This book was released on 2012-03-06 with total page 4604 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of estuaries and coasts has seen enormous growth in recent years, since changes in these areas have a large effect on the food chain, as well as on the physics and chemistry of the ocean. As the coasts and river banks around the world become more densely populated, the pressure on these ecosystems intensifies, putting a new focus on environmental, socio-economic and policy issues. Written by a team of international expert scientists, under the guidance of Chief Editors Eric Wolanski and Donald McClusky, the Treatise on Estuarine and Coastal Science, Ten Volume Set examines topics in depth, and aims to provide a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Most up-to-date reference for system-based coastal and estuarine science and management, from the inland watershed to the ocean shelf Chief editors have assembled a world-class team of volume editors and contributing authors Approach focuses on the physical, biological, chemistry, ecosystem, human, ecological and economics processes, to show how to best use multidisciplinary science to ensure earth's sustainability Provides a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Features up-to-date chapters covering a full range of topics
Download or read book Metal Geochemistry in Anoxic Marine Basins written by Lucinda Ann Jacobs and published by . This book was released on 1984 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sediments and Toxic Substances written by Wolfgang Calmano and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: In modern sediment research on contaminants five aspects are discussed which, in an overlapping succession, also reflect develop ment of knowledge on particle-associated pollutants during the past twenty-five years: (1) identification of sources and their distribution; (2) evaluation of solid/solution relations; (3) study of transfer mecha nisms to biological systems; (4) assessment of environment impact; and (5) selection and further development of remedial measures, in par ticular, of dredged materials. Scientific research and practical develop ment are still expanding in all these individual aspects. Similar to other waste materials, management of contaminated sed iments requires a holistic approach. This means that assessment of biogeochemical reactions, interfacial processes and transfer mecha nisms as well as the prognosis of long-term borderline conditions, in particular of capacity-controlling properties, should be an integrated part of the wider management scheme, i.e., the analytical and experi mental parameters should always be related to potential remediation options for a specific sediment problem. The underlying coordinated project, which was funded by the German Federal Ministry for Science and Technology (now the Federal Ministry for Education, Science, Research and Technology) provided excellent opportunities for multidisciplinary effort, bringing together biologists, chemists, engineers, geologists and other researchers. During its active phase, the group attracted much interest nationally and internationally. The group members highly appreciate the manifold contacts and invitations during the past five years.
Download or read book Biogeochemistry of Gulf of Mexico Estuaries written by Thomas S. Bianchi and published by John Wiley & Sons. This book was released on 1998-10-26 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive ecological guide to the Gulf of MexicoEstuaries Today the ecological health of the Gulf of Mexico--long the base ofvast commercial fisheries--is at risk from a potent array ofthreats, from increased nutrient inputs to the loss of coastalwetlands that impact water quality. Never before has knowledge of the biogeochemical processes of theGulf's estuaries and wetlands been so critical to its preservation,and yet until now research on this vital area has beenfragmented. Biogeochemistry of Gulf of Mexico Estuaries offers a comprehensive,integrated examination of these vital natural resources and theirecology. Featuring contributions from a diverse group of expertscientists from all regions of the Gulf Coast, thisinterdisciplinary reference provides extensive coverage of what isknown about biogeochemical processes--and the factors that regulatethem--in warm temperate and subtropical systems. Organized around aframework that integrates geomorphology, sedimentary processes,nutrient cycling, and trace metals chemistry, it not onlydemonstrates how the Gulf's estuarine systems work, but alsoestablishes a basis for how they compare with other, better-studiedtemperate estuaries. In addition, the book features afascinating--and timely--examination of the effects ofbiogeochemical processes on estuarine management. Biogeochemistry of Gulf of Mexico Estuaries will be welcomed byecologists, marine scientists, environmental activists, and anyoneinvolved with managing these precious natural resources.
Download or read book Marine Geochemistry written by Horst D. Schulz and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: A summary of the latest research in this field. The topics comprise the sedimentological examination and physical properties of the sedimentary solid phase, pore water and pore water constituents, organic matter as the driving force of most microbiological processes, biotic and abiotic redox reactions, carbonates and stable isotopes as proxies for paleoclimate reconstruction, metal enrichments in ferromanganese nodules and crusts as well as in hot vents and cold seeps on the seafloor. The current model conceptions lead to the development of different types of computer models, allowing the global mass exchanges between oceans and sediments to be balanced.
Download or read book Readings from the Treatise on Geochemistry written by Heinrich D Holland and published by Academic Press. This book was released on 2010-05-25 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: Readings from the Treatise on Geochemistry offers an interdisciplinary reference for scientists, researchers and upper undergraduate and graduate level geochemistry students that is more affordable than the full Treatise. For professionals, this volume will provide an overview of the field as a whole. For students, it will provide more in-depth introductory content than is found in broad-based geochemistry textbooks. Articles were selected from chapters across all volumes of the full Treatise, and include: The Origin and Earliest History of the Earth, Compositional Evolution of the Mantle, Evolution of Sedimentary Rocks, Soil Formation, Geochemistry of Groundwater, Geologic History of Seawater, Hydrothermal Processes, and Biogeochemistry of Primary Production in the Sea. 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 Acta Oceanographica Taiwanica written by and published by . This book was released on 1994 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sulfidic Sediments and Sedimentary Rocks written by David Rickard and published by Newnes. This book was released on 2012-12-31 with total page 813 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with sedimentary sulfides which are the most abundant authigenic minerals in sediments. Special emphasis is given to the biogeochemistry that plays such a central role in the formation of sedimentary sulfides. It will be of interest to scientists in a number of disciplines, including geology, microbiology, chemistry and environmental science. The sulfur system is important to environmental scientists considering the present and future effects of pollution and anoxia. The development of the sulfur system – particularly the characteristics of ocean anoxia over the last 200 Ma – is useful in predicting the future fate of the Earth surface system as well as in understanding the past. The biochemistry and microbiology of the sulfur system are key to understanding microbial ecology and the evolution of life. - First monograph on sedimentary sulfides, covering the ancient and modern sedimentary sulfide systems - Comprehensive, integrating chemistry, microbiology, geology and environmental science - All key references are included and discussed
Download or read book Chemical and Microbial Control of Pyrite Weathering and Its Implications to Arsenic Mobility and Sulfur and Iron Geochemistry written by Wenyi Zhu and published by . This book was released on 2010 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controls on pyrite deposition and weathering were investigated in Newark Basin (Lockatong formation) black shale. Inorganic sulfur species including pyritic S and acid volatile S were quantified in early, middle, and late Lockatong formation black shale samples obtained from the Newark Basin rock core collection. Pyritic S accounted for more than 50% of total S in Lockatong black shale and was strongly correlated to total S, yet no correlation was found between acid volatile S and total S. An inverse relationship was identified between pyritic S and acid volatile S at various depths in the formation which may indicate their redox potential-controlled interconversion. Further analysis of the redox potential index, Th/U ratio, showed that redox potential was one of the controlling factors for the deposition of the reduced sulfur species in the Newark Basin sedimentary environments. Trace metal enrichment factors showed that As and Mo were two highly enriched elements in Lockatong formation black shale. Correlation analyses show that As was closely linked to pyritic S and Mo was associated with organic matter in Lockatong black shale. The hypothesized mobilization of arsenic from pyritic black shale by a sulfide-arsenide exchange and oxidation reaction was tested with FeAsS, homogenized Lockatong formation black shale and Lockatong formation black shale pyrite incubated under oxic, hypoxic and anoxic conditions. Incubation results showed that sulfide increased arsenic mobilization to the dissolved phase from all three solids under oxic and hypoxic, but not anoxic conditions. Moreover, XANES results show that arsenic in Newark Basin black shale pyrite has the same oxidation state as that in FeAsS ( -1) and thus extend the sulfide-arsenide exchange mechanism of arsenic mobilization to sedimentary rock, black shale pyrite. This process will be most important to arsenic mobilization in aquifers where pyrite is exposed to a supply of sulfide from zones of anoxic groundwater which supports sulfate reducing bacteria and oxic groundwater or other oxidants. The direct role of microorganisms in pyrite weathering in Newark Basin black shale was examined through microbial colonization experiments. Thick biofilms were observed on the surface of pyrite bearing, polished black shale thick sections during their incubation in a subsurface groundwater well and the microbial community structure of the colonized microbes was analyzed. Colonizing microbes preferentially attached to pyrite rather than the shale matrix and the co-occurrence of bacteria-shaped pits and secondary iron minerals on pyrite were observed. 16S rDNA sequence analysis of pyrite and arsenopyrite biofilm communities indicated that most of the mineral colonizing microorganisms were members of the Fe(III)-reducing Geobacteraceae (delta-proteobacteria). Other sequences showed high similarity (>99%) with species in the [beta] and epsilon-proteobacteria that are able to oxidize iron or sulfur. These results indicate that microbes may play a critical role in the transformation of iron sulfides and their secondary minerals such as iron oxides, as well as the mobilization of trace elements from such minerals in slightly acidic black shale aquifers.
Download or read book Geochemistry of Marine Sediments written by David J. Burdige and published by Princeton University Press. This book was released on 2020-08-04 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The processes occurring in surface marine sediments have a profound effect on the local and global cycling of many elements. This graduate text presents the fundamentals of marine sediment geochemistry by examining the complex chemical, biological, and physical processes that contribute to the conversion of these sediments to rock, a process known as early diagenesis. Research over the past three decades has uncovered the fact that the oxidation of organic matter deposited in sediment acts as a causative agent for many early diagenetic changes. Summarizing and discussing these findings and providing a much-needed update to Robert Berner's Early Diagenesis: A Theoretical Approach, David J. Burdige describes the ways to quantify geochemical processes in marine sediment. By doing so, he offers a deeper understanding of the cycling of elements such as carbon, nitrogen, and phosphorus, along with important metals such as iron and manganese. No other book presents such an in-depth look at marine sediment geochemistry. Including the most up-to-date research, a complete survey of the subject, explanatory text, and the most recent mathematical formulations that have contributed to our greater understanding of early diagenesis, Geochemistry of Marine Sediments will interest graduate students of geology, geochemistry, and oceanography, as well as the broader community of earth scientists. It is poised to become the standard text on the subject for years to come.
Download or read book Environmental and Low Temperature Geochemistry written by Peter Ryan and published by John Wiley & Sons. This book was released on 2019-10-21 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental and Low-Temperature Geochemistry presents conceptual and quantitative principles of geochemistry in order to foster understanding of natural processes at and near the earth’s surface, as well as anthropogenic impacts and remediation strategies. It provides the reader with principles that allow prediction of concentration, speciation, mobility and reactivity of elements and compounds in soils, waters, sediments and air, drawing attention to both thermodynamic and kinetic controls. The scope includes atmosphere, terrestrial waters, marine waters, soils, sediments and rocks in the shallow crust; the temporal scale is present to Precambrian, and the spatial scale is nanometers to local, regional and global. This second edition of Environmental and Low-Temperature Geochemistry provides the most up-to-date status of the carbon cycle and global warming, including carbon sources, sinks, fluxes and consequences, as well as emerging evidence for (and effects of) ocean acidification. Understanding environmental problems like this requires knowledge based in fundamental principles of equilibrium, kinetics, basic laws of chemistry and physics, empirical evidence, examples from the geological record, and identification of system fluxes and reservoirs that allow us to conceptualize and understand. This edition aims to do that with clear explanations of fundamental principles of geochemistry as well as information and approaches that provide the student or researcher with knowledge to address pressing questions in environmental and geological sciences. New content in this edition includes: Focus Boxes – one every two or three pages – providing case study examples (e.g. methyl isocyanate in Bhopal, origins and health effects of asbestiform minerals), concise explanations of fundamental concepts (e.g. balancing chemical equations, isotopic fractionation, using the Keq to predict reactivity), and useful information (e.g. units of concentration, titrating to determine alkalinity, measuring redox potential of natural waters); Sections on emerging contaminants for which knowledge is rapidly increasing (e.g. perfluorinated compounds, pharmaceuticals and other domestic and industrial chemicals); Greater attention to interrelationships of inorganic, organic and biotic phases and processes; Descriptions, theoretical frameworks and examples of emerging methodologies in geochemistry research, e.g. clumped C-O isotopes to assess seawater temperature over geological time, metal stable isotopes to assess source and transport processes, X-ray absorption spectroscopy to study oxidation state and valence configuration of atoms and molecules; Additional end-of-chapter problems, including more quantitatively based questions. Two detailed case studies that examine fate and transport of organic contaminants (VOCs, PFCs), with data and interpretations presented separately. These examples consider the chemical and mineralogical composition of rocks, soils and waters in the affected system; microbial influence on the decomposition of organic compounds; the effect of reduction-oxidation on transport of Fe, As and Mn; stable isotopes and synthetic compounds as tracers of flow; geological factors that influence flow; and implications for remediation. The interdisciplinary approach and range of topics – including environmental contamination of air, water and soil as well as the processes that affect both natural and anthropogenic systems – make it well-suited for environmental geochemistry courses at universities as well as liberal arts colleges.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1989 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trace Metals in the Environment written by Patricia Elizabeth Rasmussen and published by . This book was released on 1996 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemistry of Marine Systems written by Kenneth D. Black and published by CRC Press. This book was released on 2020-02-03 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine systems vary in their sensitivities to perturbation. Perturbation may be insidious - such as increasing eutrophication of coastal areas - or it may be dramatic - such as a response to an oil spill or some other accident. Climate change may occur incrementally or it may be abrupt, and ecosystem resilience is likely to be a complex function of the interactions of the factors and species mediating key biogeochemical processes. Biogeochemistry of Marine Systems considers issues of marine system resilience, focusing on a range of marine systems that exemplify major global province types. Each system is interesting in its own right, on account of its sensitivity to natural or anthropogenic change or its importance as an ecological service provider. Each contributing author concentrates on advances of the last decade. This prime reference source for marine biogeochemists, marine ecologists, and global systems scientists provides a strong foundation for the study of the multiple marine systems undergoing change because of natural biochemical or anthropogenic factors.
