ALBERT

Description / Table of Contents: In October 1975 a Short Course on Feldspar Mineralogy was held at the Hotel Utah, Salt Lake City, in conjunction with the annual meetings of the Mineralogical Society of America. Richard A. Yund, David B. Stewart, Joseph V. Smith and Paul R. Ribbe presented workshops on x-ray single-crystal and powder diffraction methods and electron optical techniques as applied to the study of feldspars and presented eight lectures, the substance of which became the nine chapters of the first edition of Feldspar Mineralogy. That book was published by the Mineralogical Society as the second volume of its series entitled Short Course Notes. In 1980 the MSA renamed the series Reviews in Mineralogy to more accurately reflect the scope and contents of the volumes, some of which -- including Volume 5 (1st and 2nd editions), this volume and a forthcoming one on fluid inclusions --were written without presentation at a short course. It will be noted by readers experienced with feldspars that there are many new ideas appearing in Chapters 3, 4 and 5 that have neither received scrutiny by review (other than ourselves) nor survived practical tests of time in the research community. There is some danger in this, but the editor decided the greater risk was to produce a review volume soon to be outdated. Inevitably, given the different goals of individual authors in their assigned topics, some repetition of material has occurred, although usually with quite different emphases. Chapters 1, 2, 9 and 10, in which plagioclase structures and diffraction patterns and their Al,Si distributions, phase equilibria and exsolution textures are featured, are notable in this regard. The editor has attempted to cross-reference these and as many other subjects throughout the volume as feasible. This is a luxury not afforded in other books of this series produced with a short course deadline, and it, together with the detailed Table of Contents, compensates to some degree for the lack of an index. Throughout this book repeated references are made to Smith (1974a,b); these are Volumes 1 and 2 of Feldspar Minerals, an encyclopedic work written by Joseph V. Smith and published by Springer-Verlag. We are particularly indebted to Drs. Konrad Springer and H. Wiebking for permission to reproduce many figures free of charge. The editor (and hopefully this volume) benefitted greatly from numerous stimulating discussions with David B. Stewart, some of which reached a high pitch, none of which came to blows, and several of which produced some palpable scientific progress. Stewart read and criticized many of the chapters. The authors are grateful to numerous individual scientists for figures, for data in advance of publication, and for encouragement and correction.

Description / Table of Contents: Fourteen years ago the American Geological Institute (AGI) sponsored a Short Course on Chain Silicates. At that time, a substantial amount was known about the crystal chemistry and phase equilibria of pyroxenes, and this knowledge has been of fundamental importance in guiding research on pyroxenes in the years following the AGI Short Course. In 1966, single-crystal x-ray diffractometry was well advanced and good crystal structure refinements were available for jadeite, spodumene, hypersthene, c1inoferrosi1ite, orthoferrosi1ite, and omphacite; the distinction between the c1inoenstatite (pigeonite) and diopside (augite) structures had been established, and the structure of protoenstatite was known, although some doubt existed about the space group of protoenstatite. Phase diagrams for several joins in the pyroxene quadrilateral had been published, but often equilibrium had not been established in the experiments and not enough was known about the effects of pressure, oxygen fugacity, and non-quad elements such as aluminum on the phase equilibria. Also, inversion relations of Ca-poor pyroxenes were not well understood, and petrologists had just become aware of the effect of stress on orthoto-clinopyroxene transitions. In 1966 few of us would have guessed how-much new data and new analytical results would become available in the next fourteen years. Although most, if not all, of the important instrumental techniques we use today were available in 1966, the truly spectacular development and application of these techniques did not take place until the Apollo 11 samples and the attendant funding from NASA became available. Pyroxene research has profited immensely from the application of Mossbauer, optical, and infrared spectroscopy, x-ray and electron diffraction, transmission electron microscopy, automated electron microprobes, and digital computers. During these years experimentalists extended the capabilities of their equipment to examine the behavior of pyroxenes under conditions of controlled oxygen fugacity, pressure, and temperature, conditions more nearly like those under which pyroxenes crystallize in natural systems. Looking back, one remembers the excitement of seeing the first lunar samples. We were surprised at the large amounts of pigeonite and the quality of crystals unaffected by water or the presence of sodium. The influence of the lunar program on pyroxene research was extraordinary, and our understanding of pyroxene relationships in terrestrial occurrences benefited tremendously because the lunar pyroxenes provided a basis for comparison with the more complex chemical and structural behavior of terrestrial environments. Probably the most impressive development in the early lunar sample studies was the application of transmission electron microscopy to mineralogy. We were able to see exsolution and other textural features in crystals that looked homogeneous in the optical microscope, thus opening up a wide range of research possibilities that had not existed previously. Advanced crystal growth experiments, detailed phase equilibria, x-ray diffraction at high temperatures, and statistical analyses of microprobe data were all applied to lunar pyroxenes and then extended to terrestrial and meteorite investigations, making this period one of the most productive in history. In the compilation of this volume, an attempt has been made to review the essential aspects of pyroxene research, primarily those of the last ten or fifteen years. Although the largest fraction of pyroxene research has been performed in the U.S.A., significant advances have been made in other countries, particularly in Europe, Japan, Canada, and Australia, with interest and activity in these countries probably growing at a faster rate than in the United States. Recently, Deer, Howie and Zussman (DHZ) published a second edition of their volume in the Rock-Forming Minerals series, Single-Chain Silicates, Vol. 2A (John Wiley, New York, 1978). The present volume is intended to be complementary to DHZ and to provide material covered lightly or not at all in DHZ, such as electron microscopy, spectroscopy, and detailed thermodynamic treatments. However, because the range of pyroxene research has grown so much in recent years, there still are important areas not covered comprehensively in either of these volumes. Some of these areas are kinetics, diffusion, crystal defects, deformation, and nonsilicate pyroxene crystal chemistry. Because of these omissions and because this volume is intended for use with the MSA Short Course on Pyroxenes to be held at Emory University in conjunction with the November, 1980 meeting of the Society, a Symposium on Pyroxenes was organized by J. Stephen Huebner for the meeting that is designed to present the latest research results on several different topics, including those above. With DHZ, this volume, and publications from the Symposium, the student of pyroxenes should be well-equipped to advance our knowledge of pyroxenes in the decades ahead.

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: This volume represents the proceedings of a course by the same title held at Harbor House Resort and Conference Center on Nantucket Island off the coast of Massachusetts, October 22-24, 1993. Numerous minerals are known to induce pulmonary diseases. The asbestos minerals (chrysotile and asbestiform amphiboles) are by far the most infamous. However, a number of silica polymorphs, clays, and zeolites have also been studied in great detail, as have several titania polymorphs, hematite, and magnetite (which are often used as negative controls in biological experiments). In fact, the relatively recent attention received by erionite (a fibrous zeolite) has arguably made it the most notorious of the minerals studied thus far. The processes that lead to the development of disease (or pathogenesis) by minerals very likely occur at or near the mineral-fluid interface (as do many geochemical processes!). Thus the field of "mineral-induced pathogenesis" is a prime candidate for interdisciplinary research, involving mineral scientists, health scientists, petrologists, pathologists, geochemists, biochemists, and surface scientists, to name a few. The success of such an interdisciplinary approach rests on the ability of scientists in very different fields to communicate, and this is hampered by vocabulary barriers and an unfamiliarity with concepts, approaches, and problems. It can be difficult enough for a geoscientist or bioscientist to maintain fluency in the many fields tangential to his or her own field, and this problem is only exacerbated when one investigates problems that are crossdisciplinary. Nevertheless, important advances can be facilitated if these barriers are overcome. This review volume and the short course upon which it was based are intended to provide some of the necessary tools for the researcher interested in this area of interdisciplinary research. The chapters present several of the important problems, concepts, and approaches from both the geological and biological ends of the spectrum. These two extremes are partially integrated throughout the book by cross-referencing between chapters. Chapter 1 also presents a general introduction into the ways in which these two areas overlap. However, many of the areas ripe for the interdisciplinarian will become obvious after reading the various chapters. The final chapter of this book discusses some of the regulatory aspects of minerals. Ultimately, the regulatory arena is where this type of interdisciplinary approach can make an impact, and hopefully better communication between all parties will accomplish this goal. A glossary is included at the end of this book, because the complexity of scientific terms in the two fields can thwart even the most enthusiastic of individuals.