ALBERT

Description / Table of Contents: When Van't Hoff calculated the effect of solution composition on the gypsum-anhydrite transition a century ago, he solved a significant geochemical problem (Hardie, 1967). Other well known examples of the early use of chemical thermodynamics in geology are Bowen's calculations of the plagioclase melting loop and the diopside-anorthite eutectic (Bowen, 1913, 1928). Except for a few specialists, however, these techniques were largely ignored by earth scientists during the first half of the 20th century. The situation changed dramatically by the 1950's when more and better thermodynamic data on geologic materials became available, and when thermodynamic arguments of increasing sophistication began to permeate the petrologic and geochemical literature. This rejuvenation was spearheaded by D.S. Korzhinskii, H. Ramberg, J.B. Thompson, J. Verhoogen and others. Today a graduating petrologist or geochemist can be expected to have a thorough grounding in geological thermodynamics. Rapid intellectual growth in a field brings with it the difficulty of keeping abreast of parallel and diverging specialties. In order to alleviate this problem, we asked a group of active researchers to contribute up-to-date summaries relating to their specialties in the thermodynamic modeling of geological materials, in particular minerals, fluids and melts. Whereas each of these topics could fill a book, by covering the whole range we hope to emphasize similarities as much as differences in the treatment of various materials. For instance, there are useful parallels to be noted between Margules parameters and Pitzer coefficients. The emphasis here is on modeling, after the required data have been collected, and the approach ranges form theoretical to empirical. We deliberately imposed few restrictions on the authors. Some chose to interpret modeling in the rigorous thermodynamic sense, while others approached their topics from more general geochemical viewpoints. We hope that any lack of unity and balance is compensated for by a collection of lively and idiosyncratic essays in which students and professionals will find new ideas and helpful hints. If the selection appears tilted towards fluids, it is because other recent summaries have emphasized minerals and melts. The editors and authors of this volume presented a short course, entitled "Thermodynamic Modeling of Geological Materials: Minerals, Fluids amd Melts," October 22-25, 1987, at the Wickenburg Inn near Phoenix, Arizona.

Description / Table of Contents: We seek to understand the timing and processes by which our solar system formed and evolved. There are many ways to gain this understanding including theoretical calculations and remotely sensing planetary bodies with a number of techniques. However, there are a number of measurements that can only be made with planetary samples in hand. These samples can be studied in laboratories on Earth with the full range of high-precision analytical instruments available now or available in the future. The precisions and accuracies for analytical measurements in modern Earth-based laboratories are phenomenal. However, despite the fact that certain types of measurements can only be done with samples in hand, these samples will always be small in number and not necessarily representative of an entire planetary surface. Therefore, it is necessary that the planetary material scientists work hand-in-hand with the remote sensing community to combine both types of data sets. This exercise is in fact now taking place through an initiative of NASA's Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM). This initiative is named "New Views of the Moon: Integrated Remotely Sensed, Geophysical, and Sample Datasets." As preliminary results of the Lunar Prospector mission become available, and with the important results of the Galileo and Clementine missions now providing new global data sets of the Moon, it is imperative that the lunar science community synthesize these new data and integrate them with one another and with the lunar-sample database. Integrated approaches drawing upon multiple data sets can be used to address key problems of lunar origin, evolution, and resource definition and utilization. The idea to produce this Reviews in Mineralogy (RIM) volume was inspired by the realization that many types of planetary scientists and, for that matter, Earth scientists will need access to data on the planetary sample suite. Therefore, we have attempted to put together, under one cover, a comprehensive coverage of the mineralogy and petrology of planetary materials. The book is organized with an introductory chapter that introduces the reader to the nature of the planetary sample suite and provides some insights into the diverse environments from which they come. Chapter 2 on Interplanetary Dust Particles (IDPs) and Chapter 3 on Chondritic Meteorites deal with the most primitive and unevolved materials we have to work with. It is these materials that hold the clues to the nature of the solar nebula and the processes that led to the initial stages of planetary formation. Chapter 4, 5, and 6 consider samples from evolved asteroids, the Moon and Mars respectively. Chapter 7 is a brief summary chapter that compares aspects of melt-derived minerals from differing planetary environments.

Description / Table of Contents: Volume 13 of Reviews in Mineralogy presented much of our present-day knowledge of micas. At the time of that volume (1984), I mentioned that there was too much material available to attempt to cover all of the hydrous phyllosilicates in one volume. The micas were treated first because of their abundance in nature and the fact that more detailed studies had been carried out on them than on the rest of the phyllosilicates. The serpentines, kaolins, smectites, chlorites, etc. would have to wait their turn. Now, four years later, that tum has come. Hence the peculiar nature of the title of this volume. We know less about the rest of the phyllosilicates than we do about the micas, primarily because many of them are of finer grain sizes and lower crystallinities than most of the micas. As a result, we have been unable to determine as much detail regarding their structures, crystal chemistries, and origins. Nevertheless, there is a considerable body of literature about them, and this volume will attempt to collate and evaluate that literature. One compensating factor that has helped greatly in the accumulation of knowledge about these minerals is that some of them occur in large deposits that are of great economic value and thus stimulate interest. For this reason considerable emphasis in this volume will be related to the occurrence, origin, and petrology of the minerals. S. W. Bailey, Madison, Wisconsin, USA September 1,1988 The authors of this volume presented a short course by the same title to about 120 participants in Denver, Colorado, October 29-30,1988, just prior to the 100th anniversary meeting of the Geological Society of America. S. W. ("Bull") Bailey convened the course and edited this volume, his second for Reviews in Mineralogy. Because he is retiring at the end of this academic year after 38 years' teaching at the University of Wisconsin (Madison), his colleagues, friends and I (a diligent student of "Bull" thirty years ago) agreed that it would be appropriate to dedicate this volume to him, odd though it seems to have him editing a book honoring himself. He had no advance knowledge of this dedication.

Description / Table of Contents: The development of modern isotope geochemistry is without doubt attributed to the efforts, begun in the 1930's and 1940's, of Harold Urey (Columbia University and the University of Chicago) and Alfred O.C. Nier (University of Minnesota). Urey provided the ideas, theoretical foundation, the drive, and the enthusiasm, but none of this would have made a major impact on Earth Sciences without the marvelous instrument developed by Nier and later modified and improved upon by Urey, Epstein, McKinney, and McCrea at the University of Chicago. Harold Urey's interest in isotope chemistry goes back to the late 1920's when he and I.I. Rabi returned from Europe and established themselves at Columbia to introduce the then brand-new concepts of quantum mechanics to students in the United States. Urey, of course, rapidly made an impact with his discovery of deuterium in 1932, the 'magical' year in which the neutron and positron were also discovered. Urey followed up his initial important discovery with many other experimental and theoretical contributions to isotope chemistry. During this period, Al Nier developed the most sophisticated mass spectrometer then available anywhere in the world, and made a series of surveys of the isotopic ratios of as many elements as he could. Through these studies, which were carried out mainly to obtain accurate atomic weights of the various elements, Nier and his co-workers clearly demonstrated that there were some fairly large variations in the isotopic ratios of the lighter elements. However, the first inkling of a true application to the Earth Sciences didn't come until 1946 when Urey presented his Royal Society of London lecture on 'The Thermodynamic Properties of Isotopic Substances' (now a classic paper referenced in most of the published papers on stable isotope geochemistry). With the information discovered by Nier and his co-workers that limestones were about 3 percent richer in 18O than ocean water, and with his calculations of the temperature coefficient for the isotope exchange reaction between CaCO3 and H2O, Urey realized that it might be possible to apply these concepts to determining the paleotemperatures of the oceans. Urey was never one to overlook important scientific problems, regardless of the field of scientific inquiry involved. In fact, he always admonished his students to 'work only on truly important problems!' Urey, then a Professor at the University of Chicago, decided to take a hard look into the experimental problems of developing an oxygen isotope paleotemperature scale. Although the necessary accuracy had not yet been attained, the design of the Nier instrument seemed to offer a good possibility, with suitable modifications, of making the kinds of precise measurements necessary for a sufficiently accurate determination of the 18O/16O ratios of both CaCO3 (limestone) and ocean water. Enormous efforts would be required to do this, because even if all the mass spectrometric problems could be solved, every analytical and experimental procedure would have to be invented from scratch, including the experimental calibration of the temperature coefficient of the equilibrium fractionation factor between calcite and water at low temperatures. To carry out this formidable study, Urey gathered around himself a remarkable group of students, postdoctoral fellows, and technicians, as well as his paleontologist colleague Heinz Lowenstam. With Sam Epstein at the center of the effort and acting as the principal driving force, the rest, as they say, 'is history.' The marvelous nature of the Nier-Urey mass spectrometer is attested to by the fact that the basic design is still being used, and that there are now hundreds of laboratories throughout the world where this kind of work is being done. For example, the original instrument built by Sam Epstein and Chuck McKinney at Caltech in 1953 is still in use and has to date produced more than 90,000 analyses. University, government, and industrial laboratories have found these instruments to be an indispensable tool. Enormous and widely varying application of the original concepts have been made throughout the whole panoply of Earth, Atmospheric, and Planetary Sciences. In the present volume we concentrate on an important sub-field of this effort. That particular sub-field was inaugurated in Urey's laboratories at Chicago by Peter Baertschi and Sol Silverman, who developed the fluorination technique for extracting oxygen from silicate rocks and minerals. This technique was later refined and improved in the late 1950's by Sam Epstein, Hugh Taylor, Bob Clayton, and Toshiko Mayeda, and has become the prime analytical method for studying the oxygen isotope composition of rocks and minerals. The original concepts and potentialities of high-temperature oxygen isotope geochemistry were developed by Samuel Epstein and his first student, Bob Clayton. Also, Bob Clayton, A.E.J. Engel, and Sam Epstein carried out the first application of these techniques to the study of ore deposits. The first useful experimental calibrations of the high-temperature oxygen isotope geothermometers quartz-calcite-magnetite-H2O were carried out initially by Bob Clayton, and later with his first student Jim O'Neil. In the meantime, Sam Epstein and his second student, Hugh Taylor, had begun a systematic study of 18O/16O variations in igneous and metamorphic rocks, and were the first to point out the regular order of 18O/16O fractionations among coexisting minerals, as well as their potential use as geochemical tracers of petrologic processes. During this period, a parallel development of sulfur isotope geochemistry was being carried out by Harry Thode and his group at McMaster University in Canada. They developed all the mass spectrometric and extraction techniques for this element, and also provided the theoretical and experimental foundation for understanding the equilibrium and kinetic isotope chemistry of sulfur. Starting from these beginnings, most of which took place either at the University of Chicago, Caltech, or McMaster University (but also with important input from Irving Friedman's laboratory at the U.S. Geological Survey, from Athol Rafter's laboratory in New Zealand, and from Columbia, Penn State, and the Vernadsky Institute in Moscow), there followed during the decades of the late 60's, 70's, and early 80's the development and maturing of the sub-field of high-temperature stable isotope geochemistry. This discipline is now recognized as an indispensable adjunct to all studies of igneous and metamorphic rocks and meteorites, particularly in cases where fluid-rock interactions are a major focus of the study. The twin sciences of ore deposits and the study of hydrothermal systems, both largely concerned with such fluid-rock interactions, have been profoundly and completely transformed. Virtually no issue of Economic Geology now appears without 3 or 4 papers dealing with stable isotope variations. No one writes papers on the development of the hydrosphere, hydrothermal alteration, ore deposits, melt-fluid-solid interactions, etc. without taking into account the ideas and concepts of stable isotope geochemistry. Although the present volume represents only a first effort to fill the need for a general survey of this sub-field for students and for workers in other disciplines, and although it is still obviously not completely comprehensive, it should give the interested student an idea of the present 'state-of-the-art' in the field. It should also provide an entry into the pertinent literature, as well as some understanding of the basic concepts and potential applications. Some thought went into the arrangement and choice of chapters for this volume. The first three chapters focus on the theory and experimental data base for equilibrium, disequilibrium, and kinetics of stable isotope exchange reactions among geologically important minerals and fluids. The fourth chapter discusses the primordial oxygen isotope variations in the solar system prior to formation of the Earth, along with a discussion of isotopic anomalies in meteorites. The fifth chapter discusses isotopic variations in the Earth's mantle and the sixth chapter reviews the variations in the isotopic compositions of natural waters on our planet. In Chapters 7, 8, 9 and 10, these isotopic constraints and concepts are applied to various facets of the origin and evolution of igneous rocks, bringing in much material on radiogenic isotopes as well, because these problems require a multi-dimensional attack for their solution. In Chapters 11 and 12, the problems of hydrothermal alteration by meteoric waters and ocean water are considered, together with discussions of the physics and chemistry of hydrothermal systems and the 18O/16O history of ocean water. Finally, in Chapters 13 and 14, these concepts are applied to problems of metamorphic petrology and ore deposits, particularly with respect to the origins of the fluids involved in those processes. It seems clear to us (the editors) that this sub-field of stable isotope geochemistry can only grow and become even more pertinent and dominant in the future. One of the most fruitful areas to pursue is the development of microanalytical techniques so that isotopic analyses can be accurately determined on ever smaller and smaller samples. Such techniques would open up vast new territories for exploitation in every aspect of stable isotope geochemistry. Exciting new methods have recently been developed whereby a few micromoles of CO2 and SO2 can be liberated for isotopic analyses from polished sections of carbonates and sulfides by laser impact. There are also new developments in mass spectrometry like RIMS (resonance ionization mass spectrometry), Fourier transform mass spectrometry and the ion microprobe that offer considerable promise for these purposes. Stable isotope analyses of large-sized samples (even those that must be obtained by reactions of silicates with fluorinating reagents) have now become so routine and so rapid that they represent an 'easy' way to gather a lot of data in a hurry. In fact 'mass production' techniques for rapidly processing samples are starting to become prevalent, so much so that one of the biggest worries in the future may be that a flood of data will overwhelm us and outstrip our abilities to carefully define and carry out sampling strategies, as well as to think carefully and in depth about the data. An organized system of handling the D/H, 13C/12C, 15N/14N, 18O/16O, and 34S/32S data, and/or a computerized data base that could be manipulated and added to would be a useful path to follow in the future, particularly if it were integrated into a larger data base containing radiogenic isotope data, major- and trace-element analyses, electron microprobe data, x-ray crystallographic data, and petrographic data (particularly modal data on mineral abundances in the rocks).

Description / Table of Contents: This volume was published to be used as the textbook for the Short Course on Fe-Ti Oxides: Their Petrologic and Magnetic Significance, held May 24-27, 1991, organized by B.R. Frost, D.H. Lindsley, and SK Banerjee and jointly sponsored by the Mineralogical Society of America and the American Geophysical Union. It has been fourteen and a half years since the last MSA Short Course on Oxide Minerals and the appearance of Volume 3 of Reviews in Mineralogy. Much progress has been made in the interim. This is particularly evident in the coverage of the thermodynamic properties of oxide minerals: nothing in Volume 3, while in contrast, Volume 25 has three chapters (6, 7, and 8) presenting various aspects of the thermodynamics of oxide minerals; and other chapters (9, 11, 12) build extensively on thermodynamic models. The coverage of magnetic properties has also been considerably expanded (Chapters 4, 8, and 14). Finally, the interaction of oxides and silicates is emphasized in Chapters 9, 11, 12, 13, and 14. One of the prime benefits of Reviews in Mineralogy has been that any scientist can afford to have it at his or her fingertips. Because Volume 3 is out of print and will not be readily available to newcomers to our science, as much as possible we have tried to make Volume 25 a replacement for, rather than a supplement to, the earlier volume. Chapters on crystal chemistry, phase equilibria, and oxide minerals in both igneous and metamorphic rocks have been rewritten or extensively revised. The well received photographs of oxide textures in Volume 3 have been collected and expanded into a "Mini-Atlas" In Volume 25. Topics that receive less attention than in the earlier volume are oxides in lunar rocks and meteorites, and the manganese minerals. We hope that the new volume will tum out to be as useful as the previous one was.

Description / Table of Contents: This is a book exclusively devoted to three minerals: the Al2SiO5 polymorphs - andalusite, sillimanite, and kyanite. This may seem to be narrowly focused and esoteric. However, as discussed in Chapter 1, the aluminum silicate polymorphs are perhaps the most important mineral group to metamorphic petrologists. Because these minerals occur in anatectic migmatites and peraluminous granitoids, they are also important in igneous petrology. In spite of their geologic significance, there are a variety of experimental, theoretical, and field problems involving the aluminum silicates. Theoretical problems include the nature and energetics of lattice defects, order/disorder, crystalline (solid) solution, and interfacial energy. The aluminum silicates epitomize the importance of understanding the mechanisms and kinetics of heterogeneous metamorphic reactions. The difficulties in calibration of the pressure-temperature (P- T) phase equilibrium diagram illustrate the pitfalls of hydrothermal experimentation and the need to understand the methodology and uncertainties of calorimetric measurements of thermodynamic data of minerals. Thus, this book covers a wide variety of topics that must be considered in the analysis of metamorphic systems. In so doing, this volume illustrates the fact that modern metamorphic petrology demands an awareness of a wide spectrum of geologic variables and processes. In concert with the tenor of the Mineralogical Society of America Reviews in Mineralogy series, this volume is intended to provide a comprehensive review, summarizing the methods, theories and pitfalls of the various contributions on the aluminum silicates. Hopefully, this book will provide readers with a reasonably in-depth overview, and thus avoid the need for extensive, independent literature reviews. Although a concerted effort was made to give a balanced coverage of divergent theories regarding various problems involving the aluminum silicates, this critique nevertheless includes some of the author's biases. Several sections of this book present the chronological development of research on various topics, giving readers historical perspectives on the development of theories, models and biases on various problems regarding the aluminum silicates. As in all fields, several landmark studies have set the tone for the strategy of approach to problems. Although such studies have provided important steps forward in our understanding of natural phenomena, they have had the undesirable effect of entrenching biases and methodology. In this volume I have attempted to point out the deleterious effects of certain parochial approaches, an example being the aluminum immobility concept discussed in Chapter 10. In addition to their primary importance in metamorphic petrology, the aluminum silicates illustrate a wide variety of experimental, theoretical, and experimental problems. Because the Al2SiO5 polymorphs alone offer a pedagogic illustration of many important principles of modern metamorphic petrology.

Description / Table of Contents: Oxygen and silicon are the two most common elements in the earth's crust, together constituting an estimated 74.32 weight % and 83.77 atom % of crustal rocks (Mason and Moore, 1982). Thus, it is not surprising that SiO2 or silica, is the most abundant oxide on the earth's surface. In his widely cited survey, Clarke (1904) calculated that quartz alone comprises 12.0% of the crust by volume, ranking behind the mineral groups that include feldspar (59.5%) and amphibole/pyroxene (16.8%). Consequently, research into the silica system is motivated foremost by the prevalence of silica in man's immediate environment. The ubiquity of silica in igneous, metamorphic, and sedimentary rocks has led earth scientists to seek its uses as an indicator of large-scale geological processes, ranging from mountain-building to meteorite impacts. In industry, quartz has long played a prosaic but essential role as an inexpensive and relatively inert constituent of concrete aggregates, and modern electronics technology still relies on quartz oscillators. Silica phases also have played a prominent role in our understanding of the solid state. Physicists first discovered optical activity in crystals and the existence of soft modes during their investigations of quartz. Many scientists have written substantial reviews documenting the importance of silica in the earth, materials, and physical sciences. Notable among these are Robert Sosman, who followed his Properties of Silica (1927) with The Phases of Silica (1965), and Clifford Frondel, who devoted the third volume of Dana's System of Mineralogy (1962) exclusively to the silica minerals. These treatises continue to serve as encyclopedic resources for those interested in silica, and their historical analyses and descriptions of mineral varieties, morphologies, and localities will remain forever useful. Nevertheless, the past three decades have witnessed a first-order expansion of our knowledge of the silica system, and it is time to provide an updated silica review. The present volume focuses on the most recent developments, and it is intended to supplement rather than replace the earlier works of Sosman and Frondel. The contributions to this volume cover silica chemistry in the following fashion: Chapters 1 through 3 describe the crystal structures and phase transitions of silica and its stuffed derivatives. Recent studies of the low-pressure polymorphs quartz, tridymite, and cristobalite have demonstrated unusual superperiodic phases and other anomalies associated with structural transformations (Chapter 1). Spectacular progress in multianvil and diamond cell technologies has made the high-pressure regime accessible, revealing new transitions in the coesite and stishovite systems as well as the phenomenon of pressureinduced amorphization (Chapter 2). Stoichiometric substitution of cations within the frameworks of both low- and high-pressure polymorphs produces a dizzying variety of derivative compounds that are of geological and industrial importance (Chapter 3). Chapters 4 through 9 bridge the relationship between the microstructural character of real silica minerals and the behavior of silica in the geological environment. Incorporation of small amounts of H dramatically weakens quartz exposed to stress (Chapter 4). Consequently, tectonic pressures may lead not to brittle fracture but to the production of high densities of dislocations and preferred orientation in polycrystalline quartz (Chapter 5). The low pressures and temperatures in sedimentary settings may promote the crystallization of highly defective silica phases that are frequently metastable (Chapter 6); through diagenetic processes, these minerals anneal to macrocrystalline quartz (Chapter 7). The nature of the surface structure of quartz strongly influences the mechanisms and kinetics of silica dissolution in aqueous fluids (Chapter 8). Chapters 9 through 13 treat the basic physical properties of the phases of silica. Recent calorimetric studies of some of the more unusual silica compounds have added insight into the stability of the silica framework (Chapter 9). Quantum mechanical considerations of the Si-O bond have yielded a fundamental understanding of the bond lengths and angles within the polymorphous silica system (Chapter 10). Calculations based upon first-principles theory have achieved significant success in explaining and predicting silica transitions at high temperatures and pressures (Chapter 11). Spectroscopic analyses of silica (Chapters 12 and 13) have revealed vibrational behaviors in response to variations in temperature, pressure, and composition that have deepened our understanding of the dynamic interactions within the silica structure. Chapters 14 through 16 detail the uses of silica for industrial purposes. For instance, doping silica with other cations produces ceramics with low expansion on heating (Chapter 14), and high-silica zeolites are being explored for their properties as catalysts and molecular sieves (Chapter 15). High concentrations of silica dust in the workplace long have been linked with the incidence of respiratory diseases, such as silicosis, and recent evidence suggests that crystalline silica may be carcinogenic (Chapter 16).

Description / Table of Contents: The Mineralogical Society of America sponsored a short course on Contact Metamorphism, October 17-19, 1991, at the Pala Mesa Resort, Fallbrook, California, prior to its annual meeting with the Geological Society of America. As reviewed in Chapter 1, contact aureoles have unique attributes for elucidating the processes and controls of metamorphism. Within the last two decades there has been considerable evolution in our knowledge of metamorphism. This evolution spans a wide range of scales from submicroscopic analysis of grain boundaries through to regional scale analysis of contact metamorphism associated with batholith terrains. Geological sciences is becoming increasingly multidisciplinary in nature. Traditionally, contact aureoles were primarily studied by metamorphic petrologists. Their mapping of isograds and mineral zones in aureoles, coupled with microscopic analysis of the prograde metamorphic evolution of textures, structures and mineralogy, has provided an excellent framework for our understanding of contact metamorphism. However, complete understanding of the processes and controls of contact metamorphism requires a multidisciplinary analysis from a wide range of geological subdisciplines. This volume provides a multidisciplinary review of our current knowledge of contact metamorphism. As in any field of endeavor, we are provided with new questions, thereby dictating future directions of study. Hopefully, this volume will provide inspiration and direction for future research on contact metamorphism.

Description / Table of Contents: Volatile components, by which we mean those magma constituents which typically prefer to occur in the gaseous or super-critical fluid state, may influence virtually every aspect of igneous petrology. The study of volatile-bearing systems, both in nature and in the laboratory, has far exceeded the relative abundances of these components in igneous rocks, yet in many ways the words of Bowen (1928) are still broadly applicable: " ... to many petrologists a volatile component is exactly like a Maxwell demon; it does just what one may wish it to do." (Bowen, 1928, p. 282) What we hope to show in this volume are some areas of progress in understanding the behavior of magmatic volatiles and their influence on a wide variety of geological phenomena; in doing this it also becomes apparent that there remain many questions outstanding. The range of topics we have tried to cover is broad, going from atomisticscale aspects of volatile solubility mechanisms and attendant effects on melt physical properties, to the chemistry of volcanic gases and the concentrations of volatiles in magmas, to the global geochemical cycles of volatiles. The reader should quickly see that much progress has been made since Bowen voiced his concerns about Maxwell demons, but like much scientific progress, answers to old questions have prompted even greater numbers of new questions. The Voltiles in Magmas course was organized and transpired at the Napa Valley Sheraton Hotel in California, December 2-4, 1994, just prior to the Fall Meetings of the American Geophysical Union in San Francisco.

Description / Table of Contents: This volume was prepared for a short course by the same title, organized by Russell J. Hemley and Ho-kwang Mao and sponsored by the Mineralogical Society of America, December 4-6, 1998 on the campus of the University of California at Davis. High-pressure mineralogy has historically been a vital part of the geosciences, but it is only in the last few years that the field has emerged as a distinct discipline as a result of extraordinary recent developments in high-pressure techniques. The domain of mineralogy is now no less than the whole Earth, from the deep crust to the inner core-the entire range of pressures and temperatures under which the planet's constituents were formed or now exist. The primary goal of this field is to determine the physical and chemical properties of materials that underlie and control the structural and thermal state, processes, and evolution of the planet. New techniques that have come 'online' within the last couple of years make it possible to determine such properties under extreme pressures and temperatures with an accuracy and precision that rival measurements under ambient conditions. These investigations of the behavior of minerals under extreme conditions link the scale of electrons and nuclei with global processes of the Earth and other planets in the solar system. It is in this broad sense that the term 'Ultrahigh-Pressure Mineralogy' is used for the title of this volume of Reviews in Mineralogy. This volume sets out to summarize, in a tutorial fashion, knowledge in this rapidly developing area of physical science, the tools for obtaining that knowledge, and the prospects for future research. The book, divided into three sections, begins with an overview (Chapter 1) of the remarkable advances in the ability to subject minerals-not only as pristine single-crystal samples but also complex, natural mineral assemblages-to extreme pressure-temperature conditions in the laboratory. These advances parallel the development of an arsenal of analytical methods for measuring mineral behavior under those conditions. This sets the stage for section two (Chapters 2-8) which focuses on high-pressure minerals in their geological setting as a function of depth. This top-down approach begins with what we know from direct sampling of high-pressure minerals and rocks brought to the surface to detailed geophysical observations of the vast interior. The third section (Chapters 9-19) presents the material fundamentals, starting from properties of a chemical nature, such as crystal chemistry, thermochemistry, element partitioning, and melting, and moving toward the domain of mineral physics such as melt properties, equations of state, elasticity, rheology, vibrational dynamics, bonding, electronic structure, and magnetism. The Review thus moves from the complexity of rocks to their mineral components and finally to fundamental properties arising directly from the play of electrons and nuclei. The following themes crosscut its chapters. Composition of the mantle and core Our knowledge of the composition of the Earth in part is rooted in information on cosmochemical abundances of the elements and observations from the geological record. But an additional and essential part of this enterprise is the utilization of the growing information supplied by mineral physics and chemistry in detailed comparison with geophysical (e.g. seismological) observations for the bulk of the planet. There is now detailed information from a variety of sources concerning crust-mantle interactions in subduction (Liou et aI., Chapter 2; Mysen et aI., Chapter 3). Petrological, geochemical, and isotope studies indicate a mantle having significant lateral variability (McDonough and Rudnick, Chapter 4). The extent of chemical homogeneity versus layering with depth in the mantle, a question as old as the recognition of the mantle itself, is a first-order issue that threads its way throughout the book. Agee (Chapter 5) analyzes competing models in terms of mineral physics, focusing on the origin of seismic discontinuities in the upper mantle. Bina (Chapter 6) examines the constraints for the lower mantle, with particular emphasis given to the variation of the density and bulk sound velocity with depth through to the core-mantle boundary region (Jeanloz and Williams, Chapter 7). Stixrude and Brown (Chapter 8) examine bounds on the composition of the core. Mineral elasticity and the link to seismology The advent of new techniques is raising questions of the mineralogy and composition of the deep Interior to a new level. As a result of recent advances in seismology, the depth-dependence of seismic velocities and acoustic discontinuities have been determined with high precision, lateral heterogeneities in the planet have been resolved, and directional anisotropy has been determined (Chapters 6 and 7). The first-order problem of constraining the composition and temperature as a function of depth alone is being redefined by high-resolution velocity determinations that define lateral chemical or thermal variations. As discussed by Liebermann and Li (Chapter 15), measurements of acoustic velocities can now be carried out simultaneously at pressures that are an order of magnitude higher, and at temperatures that are a factor of two higher, than those possible just a few years ago. The tools are in hand to extend such studies to related properties of silicate melts (Dingwell, Chapter 13). Remarkably, the solid inner core is elastically anisotropic (Chapter 8); with developments in computational methods, condensed-matter theory now provides robust and surprising predictions for this effect (Stixrude et aI., Chapter 19), and with very recent experimental advances, elasticity measurements of core material at core pressures can be performed directly (Chapters 1 and 15). Mantle dynamics The Earth is a dynamic planet: the rheological properties of minerals define the dynamic flow and texture of material within the Earth. Measurement of rheological properties at mantle pressures is a significant challenge that can now be addressed (Weidner, Chapter 16). Deviatoric stresses down to 0.1 GPa to pressures approaching 300 GPa can be quantified in high-pressure cells using synchrotron radiation (Chapter 1). The stress levels are an appropriate scale for understanding earthquake genesis, including the nature of earthquakes that occur at great depth in subducted slabs (deep-focus earthquakes) as these slabs travel through the Earth's mantle. Newly developed high-pressure, high-precision x-ray tools such as monochromatic radiation with modern detectors with short time resolution and employing long duration times are now possible with third-generation synchrotron sources to study the rheology of deep Earth materials under pressure (Chapter 1). Fate of subducting slabs One of the principal interactions between the Earth's interior and surface is subduction of lithosphere into the mantle, resulting in arc volcanoes, chemical heterogeneity in the mantle, as well as deep-focus earthquakes (Chapters 2 and 3). Among the key chemical processes associated with subduction is the role of water in the recycling process (Prewitt and Downs, Chapter 9), which at shallower levels is essential for understanding arc volcanism. Mass and energy transport processes govern global recycling of organic and inorganic materials, integration of these constituents in the Earth's interior, the evolution (chemically and physically) of descending slabs near convergent plate boundaries, and the fate of materials below and above the descending slab. Chapters 5 and 6 discuss the evidence for entrainment and passage of slabs through the 670 km discontinuity, and the possibility of remnant slabs in the anomalous D" region near the core-mantle boundary (Chapter 7). The ultimate fate of the materials cycled to such depths may affect interactions at the core-mantle boundary and may also hold clues to the initiation of diapiric rise. The evolution and fate of a subducting slab can now be addressed by experimental simulation of slab conditions, including in situ monitoring of a simulated slab in high-pressure apparatus in situ x-ray and spectroscopic techniques. The chemistry of volatiles changes appreciably under deep Earth conditions: they can be structurally bound under pressure (Prewitt and Downs, Chapter 9). Melting Understanding pressure-induced changes in viscosity and other physical properties of melts is crucial for chemical differentiation processes ranging from models of the magma ocean in the Earth's early history to the formation of magmatic ore deposits. (Chapter 13). Recent evidence suggests that melting may take place at great depth in the mantle. Seismic observations of a low-velocity zone and seismic anisotropy at the base of the mantle have given rise to debate about the existence of regions of partial melt deep in the mantle (Chapter 7). Deep melting is also important for mantle convection from subduction of the lithosphere to the rising of hot mantle plumes. Very recent advances in determination of melting relations of mantle and core materials with laser-heating techniques are beginning to provide accurate constraints (Shen and Heinz, Chapter 12). Sometimes lost in the debate on melting curves is the fact that a decade ago, there simply were no data for most Earth materials, only guesses and (at best) approximate models. Moreover, it is now possible to carry out in situ melting studies on multi-component systems, including natural assemblages, to deep mantle conditions. These results address whether or not partial melting is responsible for the observed seismic anomalies at the base of the mantle and provide constraints for mantle convection models (Chapter 7). The enigma of the Earth's core The composition, structure, formation, evolution, and current dynamic state of the Earth's core is an area of tremendous excitement (Chapter 8). The keys to understanding the available geophysical data are the material properties of liquid and crystalline iron under core conditions. New synchrotron-based methods and new developments in theory are being applied to determine all of the pertinent physical properties, and in conjunction with seismological and geodynamic data, to develop a full understanding of the core and its interactions with the mantle (Chapter 7). There has been considerable progress in determining the melting and phase relations of iron into the megabar range with new techniques (Chapter 12). Constraints are also obtained from theory (Chapter 19). These results feed into geophysical models for the outer and inner core flow, structural state, evolution, and the geodynamo. Moreover, there is remarkable evidence that the Earth's inner core rotates at a different rate than the rest of the Earth. This evidence in turn rests on the observation that the inner core is elastically anisotropic, a subject of current experimental and theoretical study from the standpoint of mineral physics, as described above. The thermodynamic framework Whole Earth processes must be grounded in accurate thermodynamic descriptions of phase equilibria in multi-component systems, as discussed by Navrotsky (Chapter 10). New developments in this area include increasingly accurate equations of state (Duffy and Wang, Chapter 14) required for modeling of phase equilibria as well as for direct comparison with seismic density profiles through the planet. Recent developments in in situ vibrational spectroscopy and theoretical models provide a means for independently testing available thermochemical data and a means for extending those data to high pressures and temperatures (Gillet et aI., Chapter 17). Accurate determinations of crystal structures provide a basis for understanding thermochemical trends (Chapter 9). Systematics for understanding solid-solution behavior and element partitioning are now available, at least to the uppermost regions of the lower mantle (Fei, Chapter 11). New measurements for dense hydrous phases are beginning to provide answers to fundamental questions regarding their stability of hydrous phases in the mantle (Chapters 3 and 9) and the partitioning of hydrogen and oxygen between the mantle and core (Chapter 8). Novel physical phenomena at ultrahigh pressures One of the key recent findings in high-pressure research is the remarkable effect of pressure on the chemistry of the elements, at conditions ranging from deep metamorphism of crustal minerals (Chapter 2) to "contact metamorphism" at the core-mantle boundary (Chapter 7). Pressure-induced changes in Earth materials represent forefront problems in condensed-matter physics. New crystal structures appear and the chemistry of volatiles changes (Chapter 9). Pressure-induced electronic transitions and magnetic collapse in transition metal ions strongly affect mineral properties and partitioning of major, minor, and trace elements (Chapter 11). Evidence for these transitions from experiment (Chapter 18) and theory (Chapter 19) is important for developing models for Earth formation and chemical differentiation. The conventional view of structurally and chemically complex minerals of the crust giving way to simple, close-packed structures of the deep mantle and a simple iron core is being replaced by a new chemical picture wherein dense silicates, oxides, and metals exhibit unusual electronic and magnetic properties and chemistry. In the end, this framework must dovetail with seismological observations indicating an interior of considerable regional variability, both radially and laterally depending on depth (e.g. Chapters 6 and 7). New classes of global models Information concerning the chemical and physical properties of Earth materials at high pressures and temperatures is being integrated with geophysical and geochemical data to create a more comprehensive global view of the state, processes, and history of the Earth. In particular, models of the Earth's interior are being developed that reflect the details contained in the seismic record but are bounded by laboratory information on the physics and chemistry of the constituent materials. Such "Reference Earth Models" includes the development of reference data sets and modeling codes. Tools that produce seismological profiles from hypothesized mineralogies (Chapters 4 and 5) are now possible, as are tools for testing these models against 'reference' seismological data sets (Chapter 6). These models incorporate the known properties of the Earth, such as crust and lithosphere structure, and thus have both an Earth-materials and seismological orientation. Other planets The Earth cannot be understood without considering the rest of the solar system. The terrestrial planets of our solar system share a common origin, and our understanding of the formation of the Earth is tied to our understanding of the formation of its terrestrial neighbors, particularly with respect to evaluating the roles of homogeneous and heterogeneous processes during accretion. As a result of recent developments in space exploration, as well as in the scope of future planetary missions, we have new geophysical and geochemical data for the other terrestrial planets. Models for the accretion history of the Earth can now be reevaluated in relation to this new data. Experiments on known Earth materials provide the thermodynamic data necessary to calculate the high-pressure mineralogy of model compositions for the interior of Mars and Venus. Notably, the outer planets have the same volatile components as the Earth, just different abundances. Studies of the outer planets provide both an additional perspective on our own planet as well as a vast area of opportunity for application of these newly developed experimental techniques (Chapter 1 and 17). New techniques in the geosciences The utility of synchrotron radiation techniques in mineralogy has exceeded the expectations of even the most optimistic. New spectroscopic methods developed for high-pressure mineralogy are now available for characterizing small samples from other types of experiments. For example, the same techniques developed for in situ studies at high pressures and temperatures are being used to investigate microscopic inclusions such as coesite in high-pressure metamorphic rocks (Chapter 2) and deep-mantle samples as inclusions in diamond (Chapter 3). With the availability of a new generation of synchrotron radiation sources (Chapter 1) and spectroscopic techniques (Chapter 17), a systematic application of new methods, including micro tomographic x-ray analysis of whole rock samples, is now becoming routinely possible. Contributions in technology. Finally, there are implications beyond the geosciences. Mineralogy has historically has led many to conceptual and technical developments used in other fields, including metallurgy and materials science, and the new area of ultrahigh pressure mineralogy continues this tradition. As pointed out in Chapter 1, many highpressure techniques have their origins in geoscience laboratories, and in many respects, geoscience leads development of high-pressure techniques in physics, chemistry, and materials science. New developments include the application of synthetic diamond for new classes of 'large-volume' high-pressure cells. Interestingly, information on diamond stability, including its metastable growth, feeds back directly on efforts to grow large diamonds for the next generation of such high-pressure devices (Chapter 1). Microanalytical techniques, such as micro-spectroscopy and x-ray diffraction, developed for high-pressure research are now used outside of this field of research as well. The study of minerals and mineral analogs under pressure is leading to new materials. As in the synthesis of diamond itself, these same scientific approaches promise the development of novel, technological materials.

Description / Table of Contents: The publication of this volume occurs at the one-hundredth anniversary of 1905, which has been called the annus mirabilus because it was the year of a number of enormous scientific advances. Among them are four papers by Albert Einstein explaining (among other things) Brownian motion, the photoelectric effect, the special theory of relativity, and the equation E = mc2. Also of significance in 1905 was the first application of another major advance in physics, which dramatically changed the fields of Earth and planetary science. In March of 1905 (and published the following year), Ernest Rutherford presented the following in the Silliman Lectures at Yale: "The helium observed in the radioactive minerals is almost certainly due to its production from the radium and other radioactive substances contained therein. If the rate of production of helium from known weights of the different radioelements were experimentally known, it should thus be possible to determine the interval required for the production of the amount of helium observed in radioactive minerals, or, in other words, to determine the age of the mineral." Rutherford E (1906) Radioactive Transformations. Charles Scriber's Sons, NY Thus radioisotopic geochronology was born, almost immediately shattering centuries of speculative conjectures and estimates and laying the foundation for establishment of the geologic timescale, the age of the Earth and meteorites, and a quantitative understanding of the rates of processes ranging from nebular condensation to Quaternary glaciations. There is an important subplot to the historical development of radioisotopic dating over the last hundred years, which, ironically, arises directly from the subsequent history of the U-He dating method Rutherford described in 1905. Almost as soon as radioisotopic dating was invented, it was recognized that the U-He [or later the (U-Th)/He method], provided ages that were often far younger than those allowed by stratigraphic correlations or other techniques such as U/Pb dating. Clearly, as R.J. Strutt noted in 1910, He ages only provided "minimum values, because helium leaks out from the mineral, to what extent it is impossible to say" (Strutt, 1910, Proc Roy Soc Lond, Ser A 84:379-388). For several decades most attention was diverted to U/Pb and other techniques better suited to measurement of crystallization ages and establishment of the geologic timescale. Gradually it became clear that other radioisotopic systems such as K/Ar and later fission-track also provided ages that were clearly younger than formation ages. In 1910 it may have been impossible to say the extent to which He (or most other elements) leaked out of minerals, but eventually a growing understanding of thermally-activated diffusion and annealing began to shed light on the significance of such ages. The recognition that some systems can provide cooling, rather than formation, ages, was gradual and diachronous across radioisotopic systems. Most of the heavy lifting in this regard was accomplished by researchers working on the interpretation of K/Ar and fission-track ages. Ironically, Rutherfordπs He-based radioisotopic system was one of the last to be quantitatively interpreted as a thermochronometer, and has been added to K/Ar (including 40Ar/39Ar) and fission-track methods as important for constraining the medium- to low-temperature thermal histories of rocks and minerals. Thermochronology has had a slow and sometimes fitful maturation from what were once troubling age discrepancies and poorly-understood open-system behaviors, into a powerful branch of geochronology applied by Earth scientists from diverse fields. Cooling ages, coupled with quantitative understanding of crystal-scale kinetic phenomena and crustal- or landscape-scale interpretational models now provide an enormous range of insights into tectonics, geomorphology, and subjects of other fields. At the same time, blossoming of lower temperature thermochronometric approaches has inspired new perspectives into the detailed behavior of higher temperature systems that previously may have been primarily used for establishing formation ages. Increased recognition of the importance of thermal histories, combined with improved analytical precision, has motivated progress in understanding the thermochronologic behavior of U/Pb, Sm/Nd, Lu/Hf, and other systems in a wide range of minerals, filling out the temperature range accessible by thermochronologic approaches. Thus the maturation of low- and medium-temperature thermochronology has led to a fuller understanding of the significance of radioisotopic ages in general, and to one degree or another has permeated most of geochronology. Except in rare cases, the goal of thermochronology is not thermal histories themselves, but rather the geologic processes responsible for them. Thermochronometers are now routinely used for quantifying exhumation histories (tectonic or erosional), magmatism, or landscape evolution. As thermochronology has matured, so have model and interpretational approaches used to convert thermal histories into these more useful geologic histories. Low-temperature thermochronology has been especially important in this regard, as knowledge of thermal processes in the uppermost few kilometers of the crust require consideration of coupled interactions of tectonic, geodynamic, and surface processes. Exciting new developments in these fields in turn drive improved thermochronologic methods and innovative sampling approaches. The chapters This volume presents 22 chapters covering many of the important modern aspects of thermochronology. The coverage of the chapters ranges widely, including historical perspective, analytical techniques, kinetics and calibrations, modeling approaches, and interpretational methods. In general, the chapters focus on intermediate- to low-temperature thermochronometry, though some chapters cover higher temperature methods such as monazite U/Pb closure profiles, and the same theory and approaches used in low-temperature thermochronometry are generally applicable to higher temperature systems. The widely used low- to medium-temperature thermochronometric systems are reviewed in detail in these chapters, but while there are numerous chapters reviewing various aspects of the apatite (U-Th)/He system, there is no chapter singularly devoted to it, partly because of several previous reviews recently published on this topic. Chapter 1 by Reiners, Ehlers, and Zeitler provides a perspective on the history of thermochronology, comments on modern work in this field and general lessons on the potential for noise to be turned into signal. This chapter also provides a summary of the current challenges, unresolved issues, and most exciting prospects in the field. Much of the modern understanding of kinetic controls on apparent ages, thermal histories, and sampling approaches comes from decades of progress in fission-track dating, a method that remains as essential as ever, partly because of the power of track-length measurements and the depth of (at least empirical) understanding of the kinetics of track annealing. Tagami, Donelick and OπSullivan review the fundamentals of modern fission-track dating (Chapter 2). Two of the most commonly dated, well-understood, and powerful minerals dated by fission-track methods are apatite and zircon, and the specifics of modern methods for these systems and their kinetics are reviewed by Donelick, OπSullivan, and Ketcham (Chapter 3), and Tagami (Chapter 4). Although 40Ar/39Ar and (U-Th)/He dating methods followed somewhat different paths to their modern thermochronologic incarnations, they have many features in common, especially in the kinetics of diffusion and closure. Zeitler and Harrison review the concepts underlying both 40Ar/39Ar and (U-Th)/He methods (Chapter 5). Zircon was one of the first minerals dated by the (U-Th)/He method, but has only just begun to be used for thermochronometry of both bedrock and detrital samples, as reviewed by Reiners (Chapter 6). Continuous time-temperature paths from intracrystalline variations of radiogenic Ar proven perhaps the most powerful of all thermochronologic approaches, and an innovative analogous approach in He dating (4He/3He thermochronometry) is revealing remarkably powerful constraints on the extreme low temperature end of thermal histories, as reviewed by Shuster and Farley (Chapter 7). Thermochronology of detrital minerals provides unique constraints on the long-term evolution of orogens, sediment provenance, and depositional age constraints, to name a few. Bernet and Garver (Chapter 8) review the essentials of detrital zircon fission-track dating, one of the most venerable and robust of detrital thermochronometers, and in Chapter 9, Hodges, Ruhl, Wobus, and Pringle review the use of 40Ar/39Ar dating of detrital minerals, demonstrating the power of detrital muscovite ages in illuminating variations in exhumation rates in catchments over broad landscapes. (U-Th)/He thermochronometry presents several unique interpretational challenges besides new kinetics and low temperature sensitivity. One of these is long-alpha stopping distances, and its coupling with diffusion and U-Th zonation in age corrections. Dunai reviews modeling approaches to deal with these issues in interpreting low-temperature thermal histories (Chapter 10). Ketcham (Chapter 11) reviews the theory and calibration of both forward and inverse models of thermal histories from fission-track and (U-Th)/He data, and makes some important points about the interpretations of such models. Translating thermal histories into exhumational histories and their tectonic or geomorphic significance across a landscape requires quantitative understanding of the thermal structure of the crust and how it is perturbed, a review of which is presented by Ehlers (Chapter 12). Braun (Chapter 13) illustrates the power of low-temperature thermochronometry to constrain topographic evolution of landscapes over time, using PECUBE. Gallagher, Stephenson, Brown, Holmes, and Ballester present a novel method of inverse modeling of fission-track and (U-Th)/He data for thermal histories over landscapes (Chapter 14). Continuous time-temperature paths from closure profiles or their step-heating-derived equivalents are, to some degree, the holy grail of thermochronology. Harrison, Zeitler, Grove, and Lovera (Chapter 15) provide a review of the theory, measurement, and interpretation of continuous thermal histories at both intermediate and high temperatures, derived from both K-feldspar 40Ar/39Ar and monazite U/Pb dating. Extensional orogens provide a special challenge and opportunity for thermochronometry because tectonic exhumation by footwall unroofing often outstrips erosional exhumation, and often occurs at high rates. As Stockli shows (Chapter 16) thermochronology in these setting provides opportunities to measure rates of a number of important processes, as well as obtain a snapshot of crustal thermal structure and its imprint on thermochronometers with varying closure temperatures. Spotila (Chapter 17) reviews the use of thermochronology applied to tectonic geomorphology in a wide range of orogenic settings, introducing the concept of denudational maturity. Thermochronology has found great utility in economic geology, and newly developed approaches pose great potential in this area, and shown by McInnes, Evans, Fu, and Garwin in their review of the use and modeling of thermochronology of hydrothermal ore deposits (Chapter 18). The thermal histories of sedimentary basins are also critical to understanding thermal maturation of hydrocarbons, but are also critical for understanding basin formation, erosional histories of source regions, fluid flow, and climate change and other temporal signals preserved in sedimentary rocks. Armstrong (Chapter 19) reviews these issues and the use of thermochronology in deducing the thermal histories of sedimentary basins. Drawing on large datasets of bedrock apatite fission-track dates, Kohn, Gleadow, Brown, Gallagher, Lorencak, and Noble demonstrate the power of modeling, and, importantly, effectively visualizing, integrated thermotectonic and denudational histories over large regions (Chapter 20). Thermal histories of meteorites provide constraints on a wide range of fundamentally important processes, including nebular condensation and early solar-system metamorphic histories, and the dynamics of interplanetary collisions and shock metamorphism. Min reviews thermochronologic approaches to understanding meteorite thermal histories (Chapter 21), including new methods and approaches. Finally, the importance of robust models with which to interpret thermochronologic data is underscored by the review of the Software for Interpretation and Analysis of Thermochronologic Data (Chapter 22), summarized and compiled by Ehlers, for programs associated with the work of authors in this volume and others.

Description / Table of Contents: With the ever increasing spatial resolution in the characterization of microstructures, textures and chemical as well as isotopic patterns and the continuously improving sensitivity and precision in mineral chemical and isotopic analysis, increasing evidence has emerged indicating that phase relations in rocks from high-temperature environments may be modified during exhumation and cooling and that the original equilibrium phase relations may not have been preserved or that equilibrium may never have been attained fully even at high temperatures. This volume accompanies an EMU School intended bring contemporary research on mineral reaction kinetics to the attention of young researchers and to put it into the context of recent developments in related disciplines. The school and the accompanying volume cannot give a comprehensive review of the current state of geomaterials research. Rather a selection of topics, methods and concepts, which the contributors deem currently most relevant and instructive, is presented. The aim is to provide a methodologically sound insight into the theoretical foundations of mineral reaction kinetics, to help students to become acquainted with contemporary methods in experimentation and analytical techniques, and to give worked examples that illustrate recent advances in geoscience based on an improved characterization and understanding of mineral and rock systems.

Description / Table of Contents: Inhalt: 1 Tone und Tongesteine. - 2 Aufbau und Strukturprinzipien der silicatischen Tonminerale. - 3 Systematik der Tonmineralstrukturen. - 4 Tonmineralneubildung und ihre Voraussetzungen. - 5 Spezielle Tonmineralogie. - 6 Spezielle Eigenschaften der silicatischen Tonkomponenten. - 7 Tonminerale in einer anthropogen veränderten Umwelt. - 8 Hinweise zur mineralogischen Untersuchung von Tongesteinen. - Anhang: Zusammensetzung und Eigenschaften wichtiger Tonminerale. - Anmerkungen. - Literatur. - Sachregister

Description / Table of Contents: Die Tonminerale gehören u. a. wegen ihrer hohen Reaktionsempfindlichkeit gegenüber Milieuveränderungen zu den eigentümlichsten Erscheinungen unserer anorganischen Welt. Sie nehmen in einigen Bereichen der gegenwärtigen Umweltproblematik geradezu (nicht immer klar erkannte) Schlüsselpositionen ein - so z. B. bei den Waldschäden. So wurde in diesem Buch versucht, nach einleitenden Betrachtungen zur Verbreitung und Genese von Tongesteinen und neben einer zusammenfassenden Darstellung der heutigen Tonmineralogie, vor allem das Verhalten der Tone und Tonminerale durch Ableitung von ihren Struktureigenschaften auch einem breiteren Interessentenkreis verständlich zu machen.

Description / Table of Contents: Contents:Crystal Structure - Species - Crystallisation.- Crystal Chemistry of Clay Minerals.- Energy Balances.- Isotopic Composition of Clay Minerals.- Surface Properties.- Clays in Soils and Weathered Rocks.- Clays in Sedimentary Environments.- Diagenesis and Very Low-Grade Metamorphism.- Hydrothermal Process- Thermal Metamorphism.- Clays Under Extreme Conditions

Description / Table of Contents: Fluids rich in water, carbon and sulfur species and a variety of dissolved salts are a ubiquitous transport medium for heat and matter in the Earth’s interior. Fluid transport through the upper mantle and crust controls the origin of magmatism above subduction zones and results in natural risks of explosive volcanism. Fluids passing through rocks affect the chemical and heat budget of the global oceans, and can be utilized as a source of geothermal energy on land. Fluid transport is a key to the formation and the practical utilization of natural resources, from the origin of hydrothermal mineral deposits, through the exploitation of gaseous and liquid hydrocarbons as sources of energy and essential raw materials, to the subsurface storage of waste materials such as CO2. Different sources of fluids and variable paths of recycling volatile components from the hydrosphere and atmosphere through the solid interior of the Earth lead to a broad range of fluid compositions, from aqueous liquids and gases through water-rich silicate or salt melts to carbon-rich endmember compositions. Different rock regimes in the crust and mantle generate characteristic ranges of fluid composition, which depending on pressure, temperature and composition are miscible to greatly variable degrees. For example, aqueous liquids and vapors are increasingly miscible at elevated pressure and temperature. The degree of this miscibility is, however, greatly influenced by the presence of additional carbonic or salt components. A wide range of fluid–fluid interactions results from this partial miscibility of crustal fluids. Vastly different chemical and physical properties of variably miscible fluids, combined with fluid flow from one pressure – temperature regime to another, therefore have major consequences for the chemical and physical evolution of the crust and mantle. Several recent textbooks and review articles have addressed the role and diverse aspects of fluids in crustal processes. However, immiscibility of fluids and the associated phenomena of m ultiphase fluid flow are generally dealt with only in subsections with respect to specific environments and aspects of fluid mediated processes. This volume of Reviews in Mineralogy and Geochemistry attempts to fill this gap and to explicitly focus on the role that co-existing fluids play in the diverse geologic environments. It brings together the previously somewhat detached literature on fluid–fluid interactions in continental, volcanic, submarine and subduction zone environments. It emphasizes that fluid mixing and unmixing are widespread processes that may occur in all geologic environments of the entire crust and upper mantle. Despite different P-T conditions, the fundamental processes are analogous in the different settings.