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: The purpose of this short course is to examine the relations among the microscopic structure of minerals and their macroscopic thermodynamic properties. Understanding the micro-to-macro relations provides a rigorous theoretical foundation for formulation of energy relations. With such a foundation, measured parameters can be understood, and extrapolation and prediction of thermodynamic properties beyond the range of measurement can be done with more confidence than if only empirical relations are used. Mineral systems are sufficiently complex in structure and properties that a balance must be sought between rigorous complexity and useless simplicity. Eventually, even the most rigorous thermodynamic analysis requires simplifying assumptions in order to be tractable for complex minerals, and a firm foundation in the microscopic fundamentals should underlie those assumptions. The most fundamental questions of mineral physics and chemistry are "What minerals exist under given constraints of pressure, temperature, and composition, and why?" The macroscopic thermodynamic parameter defining mineral stability at a given pressure and temperature is the Gibbs free energy. The purpose of this course is to consider the microscopic factors that influence the free energy of minerals: atomic environments, bonding, and crystal structure. These factors influence the structural energy and the detailed nature of the lattice vibrations which are an important source of entropy and enthalpy at temperatures greater than 0 K. The same factors determine the relative energy of different phases, and thereby; the relative stability of different minerals. Configurational entropy terms arising from disorder also contribute to the energy and entropy. In transition metal compounds there are additional energy and entropy terms arising from the electronic configurations, leading to additional stabilizations, magnetic ordering, and, incidentally, color. Organized by Sue Kieffer and Alex Navrotsky, the course was presented by the ten authors of this book on the campus of Washington College in Chestertown, Maryland. This was the second of MSA's short courses to be given in conjunction with meetings of the American Geophysical Union.

Description / Table of Contents: Microorganisms cause mineral precipitation and dissolution and control the distribution of elements in diverse environments at and below the surface of the Earth. Conversely, mineralogical and geochemical factors exert important controls on microbial evolution and the structure of microbial communities. This was the rationale for the Short Course on Geomicrobiology presented by the Mineralogical Society of America on October 18 and 19, 1997, at the Alta Peruvian Lodge in Alta, Utah. Minerals have been known and honored since humans realized their essential contributions to the "terra firma" and stone tools thrust our species on the path of cultural evolution. Microbes are the oldest living creatures, probably inhabiting at least a few salubrious environments on the earth as early as 3.8 billion years ago. At this moment in history we are only beginning to appreciate the intimate juxtaposition and interdependence of minerals and microbes. We have been nudged into this position by the realization that our earth is finite, and the recognition of many global environmental problems that minerals and microbes contribute to, both positively and negatively. In addition, our globe may not be the only site in the solar system where 'life' arose, or may persist. What all of these concerns enunciate is that we as scientists only dimly comprehend our own dynamic "terrestrial halls." This short course and volume have been generated with great enthusiasm for grasping as much as possible of the whole panorama of possibilities that involve both the inorganic and biologic realms . Over 3600 mineral species have been defined and their relationships to each other and the environments in which they form have been documented. This vast data base, collected over the past several hundred years and constantly added to and upgraded, is a monument to the research efforts of many geoscientists focused on the inorganic realm. Much of this data has come from investigators intrigued by the novelty, beauty, and versatility of minerals, direct expressions of the chemistry and physics of geologic processes. We are now adding a new dimension to questions of mineral formation, dissolution, and distribution: what were, are, and will be the contributions of microbes to these basic components of the environment. Microbes have also been known for hundreds of years. However, their small size (0.5 to 5 µm in diameter) and the difficulties associated with identifying a species unless it was grown in the laboratory (cultured), precluded thorough analysis. The advent of molecular biology has only recently made it possible to evaluate microbial evolutionary relatedness (phylogeny) and physiological diversity. These techniques are now being applied to study of microbial populations in natural environments. It is becoming very clear that the surface of Earth is populated by far more species of microbes than there are types of minerals. We are now exploring every portion of the globe and finding the relationships under the rubric "geomicrobiology." The ocean deeps are characterized by a diversity of microorganisms, including those associated with manganese nodules. The profusion and concentration of minerals created at ocean ridges and vents matches the variety of microorganisms, large animals, and plants there. The snowy tops of mountain ranges and glaciers of Antarctica harbor not just ice but whole bacterial communities whose cellular types and activities need elucidation. The equatorial jungles and the deserts, with their enormous diversity of ecological niches, further challenge us. The diversity of geographic, geologic, and biologic environments, including some contributed by humans (e.g. mines, air-conditioning equipment), can now also be explored in detail. Modern studies use protocols developed to preserve or measure in situ chemical and physical characteristics. Electron microscopes allow direct characterization of mineral and biological morphology and internal structures. Spectroscopic techniques permit complimentary chemical analysis, including determination of oxidation states, with very high spatial resolution. Other studies quantitatively measure isotopic abudances. These data serve to distinguish biologically mediated, or biologically controlled formation of the mineral from an abiotic process and mechanism. Each ecological niche requires accurate characterization of the mineralogic and biologic entities in order for us to begin to understand the range of dynamic relationships. We can pose many questions. Is the mineral only a substrate, or is its occurrence and stability impacted by microbiologic activity and metabolic requirements? Which minerals are of microbiological rather than inorganic origin and what are the mechanisms by which organisms dictate the morphology and structure of the solid phase formed? How do organic metabolic products bind metals and change their form and distribution, with implications for metal toxicity and geochemical cycles? How do inorganic reactions such as mineral dissolution and precipitation impact microbial populations through control of their physical and chemical environments? Clearly, new and excitingly research areas exist for all varieties of scientists. Although published by the Mineralogical Society of America, the authors of this volume include microbiologists, molecular biologists, biochemists, biophysicists, bioengineers as well as biomineralogists. Here, they bring together their respective expertise and perspectives to provide disciplinary and interdisciplinary background needed to define and further explore the topic of geomicrobiology. The volume is organized so as to first introduce the nature, diversity, and metabolic impact of microorganisms and the types of solid phases they interact with. This is followed by a discussion of processes that occur at cell surfaces, interfaces between microbes and minerals, and within cells, and the resulting mineral precipitation, dissolution, and changes in aqueous geochemistry. The volume concludes with a discussion of the carbon cycle over geologic time. In detail: Nealson and Stahl acquaint us with the basic properties of prokaryotes, including their size and structure. They define the types and ranges of microorganisms and their metabolisms and describe their impacts on some important biogeochemical cycles. Barns and Nierzwicki-Bauer document the phylogenetic relationships and evolution of microorganisms, begging some fundamental questions that might be now just beyond our grasp: What was the 'last common ancestor'? The physiology, biochemistry and ecology of hyperthermophilic, and the many diverse geologically important microbial species from the lithosphere and hydrosphere, as well as some of the techniques employed, are presented. Banfield and Hamers describe and integrate the processes acting on minerals and at surfaces relevant to microorganisms, examining the factors that control mineralogy, mineral forms, and the stability of phases. Surface properties and reaction rates for dissolution, precipitation, and growth of important classes of minerals are discussed. The possible role of mineral surfaces in formation of prebiotic molecules needed to explain the origin of life is examined. Little, Wagner and Lewandowski describe biofilms, an essential interface between microbes and minerals. They demonstrate that these membranes, with their unique morphological and structural attributes, are sites where much activity related to dissolution and/or formation of minerals takes place. Biology makes it possible to move molecules and elements against a gradient. Many questions regarding the transfer of elements from minerals to microbes at this important heterogeneous interface remain. Fortin, Ferris and Beveridge review surface-mediated mineral development by bacteria. Fresh or oceanic waters, anaerobic or aerobic environments provide discretely different ecologies, bacterial entities, and resulting mineralogies. It is obvious from this presentation that investigators have just scratched the surface of microbial mineralization processes. Bazlinski and Moskowitz review the magnetic biominerals and provide insights into the environmental and biological significance of these few tens of nanometer-sized mineral products. The magnetosome chemistry and biochemistry is probably the best understood of any biologically precipitated mineral. Their formation and unique properties underscore the roles these biomaterials play in the rock magnetic record and in geochemical cycles. Tebo, Ghiorse, van Waasbergen, Siering and Caspi contribute data on the roles of Mnminerals and Mn(II) oxidation in geologic environments. Their chapter encompasses molecular genetic and biochemical investigations. Manganese oxides and oxyhydroxides are notoriously difficult to identify and the crystal chemistry of these phases is a research effort on its own. The prospect of learning how microbes utilize the multiple oxidation states of Mn (2+, 3+ and 4+) as a source of energy sharpens the motivation for interdisciplinary study. Manganese is also known as a cofactor in the production and activation of the enzymes that digest large biomolecules that must be the source of the smaller molecular species and ultimately the building blocks of C, N, 0, H required by all species. How have the mechanisms identified in the bacterial systems been transferred up the phylogenetic tree to plants and humans? This is an expanding and intriguing area for further investigation. DeVrind-de Jong and de Vrind address silicate and carbonate deposition by algae (eukaryotic photosynthetic microorganisms). This chapter documents the mechanisms of biomineralization of diatoms and coccoliths. These abundant aquatic organisms are responsible for huge volumes of siliceous sediments and calcium carbonate deposits world wide. The implications of algal biomineralization for climatic variation throughout much of the Earth's history may be quite significant. Stone leads us though a quantitative approach to evaluating reactions between organic molecules and cations. He considers available extracellular organic ligands and the roles these play in uptake of metals. He documents the basic chemical speciation and complexation for several elements, making metal to metal comparisons. Remaining challenges involve coordinating the organic and inorganic results of biologic activity. Following the discussion of biomineralization and interactions between organic compounds and cations, Silver discusses the strategies microorganisms have evolved to deal with toxic metal concentrations in solution. Beyond the fundamental biological significance, this has important implications for understanding microbial populations in contaminated environments. The impact on the geochemical form (speciation) and distribution of elements is also discussed. Nordstrom and Southam summarize sulfide mineral oxidation and dissolution kinetics and devote considerable effort to describing the specific contributions of microorganisms, mostly bacteria. Despite the vast amount of accumulated information, many unanswered questions remain. Barker, Welch and Banfield address weathering of silicate minerals. This topic encompasses not only mineralogy but geomorphology, microbiology, and geochemistry. The necessary interdisciplinary mode of these investigations is highlighted by discussion of the role(s) of bacterial nutrition, groundwater chemistry, and biochemistry. There are obvious implications for hazardous waste storage, a currently daunting and politicized topic that requires predictions over thousands to millions of years. Finally, Des Marais treats the long term evolution of the carbon cycle, adopting a biogeochemical view. He discusses the sources, sinks and the transfer of the element over geologic time. Consideration of such a basic series of questions relating to the partitioning of carbon necessitate interdisciplinary crossovers. It is a fitting conclusion to a dialogue in progress.

Description / Table of Contents: The authors of this volume presented a short course on the rare earth elements to about 80 participants in San Francisco, California, December 1-3, 1989, just prior to the fall meeting of the American Geophysical Union.

Description / Table of Contents: This volume of Reviews in Mineralogy attempts to synthesize our present understanding of certain aspects of the mineralogy and chemistry of the rock-forming carbonates. Hopefully, it reflects the presently more active areas of research. This review follows, by ten years, a major assessment of (sedimentary) carbonate minerals by Lippmann (1973). There is only minor overlap of subject material, and I hope that this difference reflects fairly how this field has developed. In some respects carbonates are unique, for they are one of the few mineral groups providing an abundant record of biological, physical, and chemical processes throughout much of geologic time. Because of their relative importance in sedimentary rocks, lowtemperature examples are given more emphasis here. Moreover, the obvious correlation with energy resources has been a significant factor contributing to the current resurgence of interest in this area. However, the broader interest in carbonates is also a reflection of their widespread occurrence in vastly different geologic environments, including metamorphic and igneous settings, as well as an appreciation of their role in both atmospheric and oceanic chemistry, both past and present. In this volume, some of the papers are general (i.e., those addressing crystal chemistry and phase relations), and they provide overviews of a fundamental nature and are of interest to many. Others are more specialized in coverage and generally reflect the different approaches used in carbonate geochemistry. The final chapter introduces transmission electron microscopy, a relatively new and powerful technique for mineralogical research that has great potential in carbonate research. Owing to the short time interval between the completion of manuscripts and publication, much of the newer material in this volume is still "fresh." The various reviewers, all gratefully acknowledged, were expeditious in their efforts. A hurried schedule, however, allows for unnoticed errors to persist; these should be brought to my attention.

Description / Table of Contents: Geochemistry is a science that is based on an understanding of chemical processes in the earth. One of the principal tools available to the chemist for understanding systems at equilibrium is thermodynamics. The awareness and application of thermodynamic techniques has increased at a very fast pace in geosciences; in fact, one may be so bold as to say that thermodynamics in geology has reached the "mature" stage, although much future thermodynamic research is certainly needed. However, the natural processes in the earth are often sluggish enough that a particular system may not reach equilibrium. This observation is being supported constantly by new experimental and field data available to the geochemist e.g. the non-applicability of the phase rule in some assemblages, the compositional inhomogeneities of mineral grains, the partial reaction rims surrounding original minerals, the lack of isotopic equilibration or the absence of minerals (e.g. dolomite), which should be present according to thermodynamics. The need to apply kinetics has produced a large number of papers dealing with kinetics in geochemistry. As an initial response to this growing field, a conference on geochemical transport and kinetics was conducted at Airlie House, VA, in 1973, sponsored by the Carnegie Institution of Washington. The papers there dealt with several kinetic topics including diffusion, exsolution, metasomatism and metamorphic layering. Since 1973 the number of kinetic papers has continued to increase greatly. Therefore, the time is ripe for a Short Course in Kinetics, which brings together the fundamentals needed to explain field observations using kinetic data. It is hoped that this book may serve, not only as a reference for researchers dealing with the rates of geochemical processes, but also as a text in courses on geochemical kinetics. One of us has found this need of a text in teaching a graduate course on geochemical kinetics at Harvard and at Penn State during the past several years. Finally, it is our hope that the book may itself further even more research into the rates of geochemical processes and into the quantification of geochemical observations. The book is organized with a rough temperature gradient in mind, i.e. low temperature kinetics at the beginning and igneous kinetics at the end (no prejudices are intended with this scheme!). However, the topics in each chapter are general enough that they can be applied often to any geochemical domain: sedimentary, metamorphic or igneous. The theory of kinetics operates at two complementary levels: the phenomenological and the atomistic. The former relies on macroscopic variables (e.g. temperature or concentrations) to describe the rates of reactions or the rates of transport; the latter relates the rates to the basic forces operating between the particular atomic or molecular species of any system. This book deals with both descriptions of the kinetics of geochemical processes. Chapter one sets the framework for the phenomenological theory of reaction rates. If any geochemical reaction is to be described quantitatively, the rate law must be experimentally obtained in a kinetically sound manner and the reaction mechanism must be understood. This applies to heterogeneous fluid-rock reactions such as those occurring during metamorphism, hydrothermal alteration or weathering as well as to homogeneous reactions. Chapter 2 extends the theory to the global kinetics of geochemical cycles. This enables the kinetic concepts of stability and feedback to be applied to the cycling of elements in the many reservoirs of the earth. Chapter 3 applies the phenomenological treatment of chapter 1 to diagenesis and weathering. The rate of dissolution of minerals as well as the chemical evolution of pore waters are discussed. The atomistic basis of rates of reaction, transition state theory, is introduced in Chapter 4. Transition state theory can be applied to relate the rate constants of geochemical reactions to the atomic processes taking place. This includes not only homogeneous reactions but also reactions that occur at the surface of minerals. Chapter 5 discusses the theory of irreversible thermodynamics and its application to petrology. The use of the second law of thermodynamics along with the expressions for the rate of entropy production in a system have been used successfully since 1935 to describe kinetic phenomena. The chapter applies the concepts to the growth of minerals during metamorphism as well as to the formation of differentiated layers (banding) in petrology. Chapter 6 describes the phenomenological theory of diffusion both in aqueous solutions and in minerals. In particular, the multicomponent nature of diffusion and its consequence in natural systems is elaborated. Chapter 7 provides the atomistic basis for the rates of reactions in minerals. Understanding of the rates of diffusion, conduction, order-disorder reactions or exsolution in minerals depends on proper description of the defects in the various mineral structures. Chapter 8 provides the kinetic theory of crystal nucleation and growth. While many of the concepts in the chapter can be applied to aqueous systems, the emphasis is on igneous processes occurring during crystallization of a melt. To fully understand both the mineral composition as well as the texture of igneous rocks, the processes whereby new crystals form and grow must be quantified by using kinetic theory. Due to space and time limitations (kinetics!) some topics have not been covered in detail. In particular, the mathematical solution of diffusion or conduction equations is discussed very well by Crank in his book, Mathematics of Diffusion, and so is not covered to a great extent here. The treatment of fluid flow (e.g. convection) is also not covered in the text.

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: This book reviews current thinking on the fundamental processes that control chemical weathering of silicates, including the physical chemistry of reactions at mineral surfaces, the role of experimental design in isolating and quantifying these reactions, and the complex roles that water chemistry, hydrology, biology, and climate play in weathering of natural systems. The chapters in this volume are arranged to parallel this order of development from theoretical considerations to experimental studies to characterization of natural systems. Secondly, the book is meant to serve as a reference from which researchers can readily retrieve quantitative weathering rate data for specific minerals under detailed experimental controls or for natural weathering conditions. Toward this objective, the authors were encouraged to tabulate available weathering rate data for their specific topics. Finally this volume serves as a forum in which suggestions and speculations concerning the direction of future weathering research are discussed. The comprehensive nature of the volume provides opportunities to address important temporal and spacial issues that often separate the work and thinking of investigators working on specific aspects of chemical weathering. As has become apparent in assembling this volume, a number of important issues related to chemical weathering are unresolved. No effort was made to reach a consensus on these issues. Divergences in opinion were accepted between various authors and are apparent in the chapters of this volume.

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.