Studies of Sr isotopic composition of thousands of samples of marine sediments and fossils have yielded a curve of 87Sr/86Sr versus age for seawater Sr that extends back to 1 billion years. The ratio has fluctuated with large amplitude during this time period, and because the ratio is always uniform in the oceans globally at any one time, it is useful as a stratigraphic correlation and age-dating tool. The ratio also appears to reflect major tectonic and climatic events in Earth history and hence provides clues as to the causes, timing, and consequences of those events. The seawater 87Sr/86Sr ratio is generally high during periods marked by continent-continent collisions, and lower when continental topography is subdued, and seafloor generation rates are high. There is evidence that major shifts in the seawater ratio can be ascribed to specific orogenic events and correlate with large shifts in global climate.
This volume provides an overview of (1) the physical and chemical foundations of dating methods and (2) the applications of dating methods in the geological sciences, biology, and archaeology, in almost 200 articles from over 200 international authors. It will serve as the most comprehensive treatise on widely accepted dating methods in the earth sciences and related fields. No other volume has a similar scope, in terms of methods and applications and particularly time range. Dating methods are used to determine the timing and rate of various processes, such as sedimentation (terrestrial and marine), tectonics, volcanism, geomorphological change, cooling rates, crystallization, fluid flow, glaciation, climate change and evolution. The volume includes applications in terrestrial and extraterrestrial settings, the burgeoning field of molecular-clock dating and topics in the intersection of earth sciences with forensics. The content covers a broad range of techniques and applications. All major accepted dating techniques are included, as well as all major datable materials.
This is a complete and authoritative reference text on an evolving field. Over 200 international scientists have written over 340 separate topics on different aspects of geochemistry including organics, trace elements, isotopes, high and low temperature geochemistry, and ore deposits, to name just a few.
The Encyclopedia is a complete and authoritative reference work for this rapidly evolving field. Over 200 international scientists, each experts in their specialties, have written over 330 separate topics on different aspects of geochemistry including geochemical thermodynamics and kinetics, isotope and organic geochemistry, meteorites and cosmochemistry, the carbon cycle and climate, trace elements, geochemistry of high and low temperature processes, and ore deposition, to name just a few. The geochemical behavior of the elements is described as is the state of the art in analytical geochemistry. Each topic incorporates cross-referencing to related articles, and also has its own reference list to lead the reader to the essential articles within the published literature. The entries are arranged alphabetically, for easy access, and the subject and citation indices are comprehensive and extensive. Geochemistry applies chemical techniques and approaches to understanding the Earth and how it works. It touches upon almost every aspect of earth science, ranging from applied topics such as the search for energy and mineral resources, environmental pollution, and climate change to more basic questions such as the Earth’s origin and composition, the origin and evolution of life, rock weathering and metamorphism, and the pattern of ocean and mantle circulation. Geochemistry allows us to assign absolute ages to events in Earth’s history, to trace the flow of ocean water both now and in the past, trace sediments into subduction zones and arc volcanoes, and trace petroleum to its source rock and ultimately the environment in which it formed. The earliest of evidence of life is chemical and isotopic traces, not fossils, preserved in rocks. Geochemistry has allowed us to unravel the history of the ice ages and thereby deduce their cause. Geochemistry allows us to determine the swings in Earth’s surface temperatures during the ice ages, determine the temperatures and pressures at which rocks have been metamorphosed, and the rates at which ancient magma chambers cooled and crystallized. The field has grown rapidly more sophisticated, in both analytical techniques that can determine elemental concentrations or isotope ratios with exquisite precision and in computational modeling on scales ranging from atomic to planetary.
Carbon dioxide is the most important greenhouse gas after water vapor in the atmosphere of the earth. More than 98% of the carbon of the atmosphere-ocean system is stored in the oceans as dissolved inorganic carbon. The key for understanding critical processes of the marine carbon cycle is a sound knowledge of the seawater carbonate chemistry, including equilibrium and nonequilibrium properties as well as stable isotope fractionation. Presenting the first coherent text describing equilibrium and nonequilibrium properties and stable isotope fractionation among the elements of the carbonate system. This volume presents an overview and a synthesis of these subjects which should be useful for graduate students and researchers in various fields such as biogeochemistry, chemical oceanography, paleoceanography, marine biology, marine chemistry, marine geology, and others. The volume includes an introduction to the equilibrium properties of the carbonate system in which basic concepts such as equilibrium constants, alkalinity, pH scales, and buffering are discussed. It also deals with the nonequilibrium properties of the seawater carbonate chemistry. Whereas principle of chemical kinetics are recapitulated, reaction rates and relaxation times of the carbonate system are considered in details. The book also provides a general introduction to stable isotope fractionation and describes the partitioning of carbon, oxygen, and boron isotopes between the species of the carbonate system. The appendix contains formulas for the equilibrium constants of the carbonate system, mathematical expressions to calculate carbonate system parameters, answers to exercises and more.
'Deep-Sea Sediments' focuses on the sedimentary processes operating within the various modern and ancient deep-sea environments. The chapters track the way of sedimentary particles from continental erosion or production in the marine realm, to transport into the deep sea, to final deposition on the sea floor.
The analysis of stable isotope ratios represents one of the most exciting new technical advances in environmental sciences. In this book, leading experts offer the first survey of applications of stable isotope analysis to ecological research. Central topics are - plant physiology studies - food webs and animal metabolism - biogeochemical fluxes. Extensive coverage is given to natural isotopes of carbon, hydrogen, oxygen, nitrogen, sulfur, and strontium in both terrestrial and marine ecosystems. Ecologists of diverse research interests, as well as agronomists, anthropologists, and geochemists will value this overview for its wealth of information on theoretical background, experimental approaches, and technical design of studies utilizing stable isotope ratios.
