The drilling site of the KTB is located on the western margin of the Bohemian Massif, a few kilometers south of the structurally important Saxothur ing ian/Moldanubian boundary of the central European Hercynian orogene and several kilometers east of one of the most important Permian-Mesozoic strike-slip zones of central Europe, the Franconian line. The borehole will be drilled in the Moldanubian segment (Fig. 1). o -::: --. . . . . . . . -. . -. D Il1O, Fig. l: Geological map of the Central Europe Variscides and location of borehole From geographical and political points of view, the drill site is located in northern Bavaria in the Oberpfalz province near the towns of Windischeschenbach and Erbendorf about 40 km southeast of Bayreuth. TARGETS AND RESEARCH TOPICS 'The Continental Deep Drilling program of the Federal Republic of Germany (KTB) is a project of basic geoscientific research. The program and goals of this project have been set by a board of the Senate Commission on Geosciences of the German Research Foundation (DFG). The technical concept of the drilling, sampling, coring and logging programs corresponds to these goals. The upper limit of the budget of 450 million DM is approved by the Federal Ministry of Research and Development (Bundesministerium fuer Forschung und Technologie).

The triennial International Alloy Conferences (lACs) aim at the identification and promotion of the common elements developed in the study, either experimental, phenomenological, or theoretical and computational, of materials properties across materials types, from metals to minerals. To accomplish this goal, the lACs bring together scientists from a wide spectrum of materials science including experiment, theory, modeling, and computation, incorporating a broad range of materials properties. The first lAC, lAC-I, took place in Athens, Greece, June 16-21, 1996. The present volume of proceedings contains the papers presented at IAC-2, that took place in Davos, Switzerland, August 8-13, 1999. The topics in this book fall into several themes, which suggest a number of different classification schemes. We have chosen a scheme that classifies the papers in the volume into the categories Microstructural Properties; Ordering, Kinetics and Diffusion; Magnetic Properties and Elastic Properties. We have juxtaposed apparently disparate of revealing the dynamic character approaches to similar physical processes, in the hope of the processes under consideration. We hope this will invigorate new kinds of discussion and reveal challenges and new avenues to the description and prediction of properties of materials in the solid state and the conditions that produce them.

As this excellent book demonstrates, the study of comets has now reached the fas cinating stage where we understand comets in general simple tenns while, at the same time, we are uncertain about practically all the details of cometary nature, structure, processes, and origin. In every aspect, even including dynamics, a choice among several or many competing theories is made impossible simply by the lack of detailed knowledge. The space missions, snapshot studies of two comets, partic ularly the one that immortalizes the name of Sir Edmund Halley, have produced a huge mass of valuable new infonnation and a number of surprises. Nonetheless, we face the tantalizing realization that we have obtained only a fleeting glance at two of perhaps a hundred billion (lOll) or more comets with possibly differing natures, origins, and physical histories. To my personal satisfaction, comets seem to have discrete nuclei made up of dirty snowballs, as I concluded four decades ago, but perhaps they are more like frozen rubbish piles.

Reviewers of the German edition of this book found that the text deals with facts and descriptions of limestones rather than with glo- bal speculations on facies models or large-scale sedimentation pat- terns. The book is neither a picture-book nor a recipe-book for facies interpretation of carbonates, but an attempt to summarize the present "state of the art" of a rather small but increasingly more im- portant part of geology. The book is written for advanced undergraduate and post-grad- uate students as well as for research workers and exploration geol- ogists who need rapid and intensive training in modern methods of microfacies analysis. The book should facilitate decisions about which methods to use in one's own investigations, and where to look for comparative studies. Microfacies interpretation of carbonate rocks can not rely solely on the investigation of sedimentological and paleontological thin- section data, but must also consider geological and palecological cri- teria. It is beyond the scope of this book to describe all of these as- pects. However, broader applications are indicated in the chapters dealing with the relationships between geochemical as well as physi- cal data and the depositional and diagenetic fabric oflimestones.

The original Russian edition of the monograph Paleozoic salt forma- tions ofthe world was published by Nedra, Moscow, in 1974. The description of salt basins was given as of 1970-1971 and based on the literature available at that time. Additional evidence was pre- sented in History of Paleozoic salt accumulation (Nauka, Novosibirsk 1978), with abrief account of new basins of Paleozoic salt accumula- tion. These two books complement each other and have one common list of references, the former providing the material which in the latter is the basis for the major trends in the history of evaporite sedimenta- tion in the Paleozoic. History ofPaleozoic salt accumulation was the first ofthe two books to be published in English (Springer, Berlin, Heidelberg, New York 1981). The present book is the first synthesis dealing with specific Paleozoic salt formations and some salt basins. However, since the first edition was published 10 years ago, new data since then allow more accurate and detailed description of composition, structure, and dis- tribution patterns of salt deposits within Paleozoic evaporite basins. New basins have also been found in some regions of the Earth. The author has attempted to give more complete characterization of Paleo- zoic salt basins using the data available as of 1981.

Do changes in stratospheric ozone relate to changes in UV-B irradiance and do both relate to life on Earth? This volume presents the latest data available in the basic scientific disciplines associated with these questions. The key topics are the interactive factors between the various research elements and the measurements needed to both validate ozone depletion and monitor UV flux changes in the biosphere.

The intensification of the production of silicate materials and products makes a de tailed theoretical study of the processes underlying their manufacture and service more and more urgent. The thermodynamic method is of great importance for studying chemical reac tions of silicate technology. Together with a study of the rate and mechanism of sub stance transfer, it permits obtaining necessary data for the efficient operation of technological processes. The progress of science in recent years has solved numerous problems in the field of the physical chemistry of silicates. The great progress in deciphering silicate structures, and working out methods of the synthesis of minerals and studying their properties must be mentioned. New methods of determining thermic constants have appeared. In future these methods should be more widely used for determining the heats of the silicate forma tion and related compounds in crystalline and vitreous state. This concerns in par ticular the system - CaO - Ab03 - Fe203 - Si0 - H 0 -which is of great impor 2 2 tance for the technology of cement and concrete, ceramics, refractories and glass."

Documenting a joint Chinese-European study of mesothermal lode gold deposits from early Precambrian rocks of E. Hebei Province (NE China), introductory chapters on gold deposits, and the basement geology of the Sino-Korean Platform are followed by detailed descriptions of the individual gold desposits. These include descriptions of the lithology and structure of the host rocks, ore geochemistry and petrography, and wall-rock alteration. Radiometric ages, fluid inclusion data, and C-O-H-S-Pb isotopic compositions of ore and gangue minerals constrain the timing, physical conditions and the possible origin of mineralization. An important conclusion is that, in contrast to the Archean greenstone-hosted gold desposits in Canada, Australia and Africa, the Chinese examples occur in high-grade polymetamorphic rocks, and the main impetus for mineralization was tectonism and granitic magmatism of the late Mesozoic Yanshanian orogeny. This book will be of considerable value as a source of specific information and extensive references about gold deposits and Archean geology in NE China, and should be equally interesting to geologists working on Archean gold geology and those concerned with Mesozoic Circum-Pacific metallogeny.

One of the most fundamental discoveries of the solar system was the detection of four moons in orbit around Jupiter by Galileo Galilei in 1610. The discovery was significant not only in the context of Jupiter; it gave credence to and was instrumental in firmly establishing the heliocentric system of Nicolaus Copernicus. Almost four centuries after Galileo's discovery, exten sive observations by the two Voyager spacecrafts have once again revolu tionized our thinking about the major planets, their composition, structure, origin, and evolution. This book is an attempt at summarizing our present understanding of the atmospheres and ionospheres in the outer solar system, with particular emphasis on the relevant physics and chemistry. I was motivat ed to prepare this manuscript for the following reasons. First, after under going rapid expansion in the recent past, the subject has finally attained suf ficient maturity to warrant a monograph of its own. Second, I have felt that as a result of recent observations, new and challenging problems have arisen whose resolution requires unconventional analysis and theoretical interpreta tion of existing data, as well as the collection of new kinds of data. I believe the time is ripe to put these issues in the appropriate scientific perspective, with the hope of stimulating novel theoretical, observational, and laboratory studies. I have highlighted the significant scientific problems throughout the book, especially at the end of each chapter.

The first edition of this book was published in 1965 and its French translation in 1966. The revised second edition followed in 1967 and its Russian translation became available in 1969. Since then, many new petrographic observations and experimental data elucidat- ing reactions in metamorphic rocks have made a new approach in the study of metamorphic transformation desirable and possible. It is felt that this new approach, attempted in this book, leads to a better unders- tanding of rock metamorphism. The concept of metamorphic facies and subfacies considers asso- ciations of mineral assemblages from diverse bulk compositions as characteristic of a certain pressure-temperature range. As new petrographic observations accumulated, it became increasingly difficult to accommodate this information within a manageable framework of metamorphic facies and subfacies. Instead, it turned out that mineral assemblages due to reactions in common rocks of a particular composi- tion provide suitable indicators of metamorphic conditions. Metamorphic zones, defined on the basis of mineral reactions, very effectively display the evolution of metamorphic rocks. Thus the im- portance ofreactions in metamorphic rocks is emphasized. Experimen- tal calibration of mineral reactions makes it possible to distinguish reac- tions which are of petrogenetic significance from those which are not. This distinction provides guidance in petrographic investigations un- dertaken with the object of deducing the physical conditions of metamorphism.

The origin of granite has for long fascinated geologists though serious debate on the topic may be said to date from a famous meeting of the Geological Society of France in 1847. My own introduction to the subject began exactly one hundred years later when, in an interview with Profes sor H. H. Read, I entered his study as an amateur fossil collector and left it as a committed granite petrologist - after just ten minutes I can hardly aspire to convert my reader in so dramatic a way, yet this book is an attempt, however inadequate, to pass on the enthusiasm that I inherited, and which has been reinforced by innumerable discussions on the outcrop with granitologists of many nationalities and of many shades of opinion. Since the 1960s, interest in granites has been greatly stimulated by the thesis that granites image their source rocks in the inaccessible deep crust, and that their diversity is the result of varying global tectonic context. So great a body of new data and new ideas has accumulated that my attempt to review the whole field of granite studies must carry with it a possible charge of arrogance, especially as I have adopted the teaching device of presenting the material from a personal point of view with its thinly disguised prejudices."

This book presents the third volume of a complete development of the new structural classification of minerals, which is based on the internal crystal structure, and is therefore its natural classification. Because of the large domain of the mineral kingdom, this work is divided in three volumes, in which the minerals are ordered from the structurally simple to the more complex.

Audience: This work will be of particular interest to teachers and research workers of in mineralogy, and in inorganic crystal structures in academia.

Biominerals are generated by the subtle interaction of biological organization and mineral growth. They belong both to the living and the inanimate world and as such their genesis is among the most intri guing and fundamental subjects in science. However, the conceptual and technical resources that are available in physical chemistry and in the biological sciences is often inadequate for the elucidation of the pro blems involved, and hence this field is particularly difficult to ex plore. This may be an important reason why fundamental research on bio mineralization mechanisms has traditionally been carried out by a com paratively small group of scientists. There are signs, however, that the situation is ripe for a change. Various meetings on biomineralization have been organized in the last few years, particularly in the medical sector. It is generally felt that further developments in the therapy of bone and tooth diseases will be largely dependent on an improved understanding of the fundamen tal underlying mechanisms of biomineralization."

Students of a phenomenon as common but complex as andesite genesis often are overwhelmed by, or overlook, the volume and diversity of relevant information. Thus there is need for periodic overview even in the absence of a dramatic breakthrough which "solves the andesite problem" and even though new ideas and data keep the issues in a state of flux. Thus I have summarized the subject through mid.1980 from my perspective to help clarify the long-standing problem and to identify profitable areas for future research. Overviews are more easily justified than achieved and there are fundamental differences of opinion concerning how to go about them. It is professionally dangerous and therefore uncom mon for single authors, especially those under 35 such as I, to summarize a broad, active field of science in book-length thor oughness. Review articles in journals, multi-authored books, or symposia proceedings appear instead. The single-authored approach is intimidating in scale and can result in loss of thoroughness or authority on individual topics. The alternatives lack scope or integration or both."

The papers of this book are based on a Symposium on Numerical Simulation in Oil Recovery held at the Institute for Mathematics and its Applications. The major research emphasis is on the modeling of fractures, heterogeneities, viscous fingering, and diffusion-dispersion effects in the flow in porous media. This volume contains seventeen comprehensive papers on the latest developments in this exciting subject. Its diverse presentation brings together the various disciplines of applied mathematics, chemical engineering, physics and hydrology.

Professor OTTO BRAITSCH'S Entstehung und Stoffbestand der Salz- lagerstiitten has since its publication in 1962 enjoyed a reputation as the most complete and authoritative treatment, in any language, of the geochemistry of evaporites. The issue of this translation will now make it accessible to a much wider circle of readers. The years since first publica- tion of the German edition have seen a great surge of discussion and research on evaporites among English-speaking geologists, and while BRAITSCH'S work was important to some of these it can now no longer be ignored by any. It may be worth pointing out that, title notwithstanding, this volume takes as its subject not only the salts but all evaporite minerals and rocks, but that it makes no attempt to go beyond the geochemical evidence in discussing the origin of these evaporites. The reader should not expect to find here any extensive discussion of paleogeography and stratigraphy, or even petrographic detail. Within its scope of geochemistry and mineral- ogy the coverage is extensive.

Today large numbers of geoscientists apply thermodynamic theory to solu tions of a variety of problems in earth and planetary sciences. For most problems in chemistry, the application of thermodynamics is direct and rewarding. Geoscientists, however, deal with complex inorganic and organic substances. The complexities in the nature of mineralogical substances arise due to their involved crystal structure and multicomponental character. As a result, thermochemical solutions of many geological-planetological problems should be attempted only with a clear understanding of the crystal-chemical and thermochemical character of each mineral. The subject of physical geochemistry deals with the elucidation and application of physico-chemical principles to geosciences. Thermodynamics of mineral phases and crystalline solutions form an integral part of it. Developments in mineralogic thermody namics in recent years have been very encouraging, but do not easily reach many geoscientists interested mainly in applications. This series is to provide geoscientists and planetary scientists with current information on the develop ments in thermodynamics of mineral systems, and also provide the active researcher in this rapidly developing field with a forum through which he can popularize the important conclusions of his work. In the first several volumes, we plan to publish original contributions (with an abundant supply of back ground material for the uninitiated reader) and thoughtful reviews from a number of researchers on mineralogic thermodynamics, on the application of thermochemistry to planetary phase equilibria (including meteorites), and on kinetics of geochemical reactions."

Many interesting and perplexing questions arise in connection with the highly potassic volcanic associa- tion dominated by mafic and ultramafic rocks contain- ing leucite. Its occurrence is very restricted as compar- ed with the olivine-basalt trachyte kindred, but it is distributed at widely scattered points on all the conti- nents, and its chemical and petrographic individuality is both remarkable and constant. A considerable litera- ture is available related to the mineralogy, petrology, geochemistry, phase chemistry, distribution, and origin of this interesting suite of rocks. It seemed that there was a genuine need for a review-synthesis of all these data, which would be intelligible to a wide spectrum of advanced students and professionals in the earth sciences. The monograph may be divided into two parts. The first part consists of six chapters in which the mineralogical and chemical peculiarities of leucite- bearing rocks and their nomenclature, petrology, min- eralogy, distribution, and physical and chemical condi- tions of formation are discussed. Phase equilibria stud- ies on many leucite-bearing ternary, pseudoternary, quaternary, and pseudoquaternary joins and systems, studied by different investigators at variable tempera- tures in air, are described in the second part in Chap- ters 7 to 12. Survival of leucite and formation of pseu- doleucite is discussed in Chapter 13. Leucite-bearing synthetic and natural rock systems studied at different temperatures under variable pressures in presence or absence of water, are summarized in Chapters 14 and 15.

Analyses data on the composition, structure and formation of various petroleum hydrocarbons: the alkanes, cycloalkanes and arenes. Attention is paid to biological markers, com- pounds that may have preserved the main structural features of the original biogenic molecules. Concepts of chemical classification of crude oils are reviewed with respect to the molecular mass distribution of biological markers, and the genesis and chemical evolution of petroleum hydrocarbons are discussed.

and their identification obviates individual thermochemical studies on every genus. The stability relations among sedimentary carbonate minerals are now more or less well known. The common rock-forming minerals cal cite and dolomite are indeed stable phases in the pertinent systems. Most other carbonate minerals of similar composition which are known to occur in the younger sediments are metastable with respect to calcite, dolomite, and magnesite. This implies that the sedimentation of carbon ates is determined only in part by stability relations. Kinetic factors, which allow the formation of metastable minerals, appear to be more important. Although the diagenetic transformations leading to stable minerals take place by virtue of thermodynamic requirements, the reac tions themselves are triggered by kinetic factors as well. Some of the reactions leading from metastable to stable carbonate assemblages are susceptible to simulation in the laboratory; others (e. g. dolomitization) appear to be so slow that they can be studied only in analogous systems characterized by reasonable reaction rates. In all attempts to explain the possible mechanisms of such reactions, we must consider the crystal structures of the final products as well as of the starting materials. This is another viewpoint from which mineralogy is important to carbonate petrology, if we regard the crystal chemistry of minerals as a part of mineralogy. A certain parallelism with clay mineralogy suggests itself."

Considerable progress in understanding how inhaled minerals cause disease in man has been made in the past two decades. This is mostly due to the great amount of human, animal and cell multidisciplinary studies carried out on silica, asbestos and asbestiforms all around the world. Two previous NATO Workshops on "In Vitro Effects of Mineral Dusts on Cells", have been published in the NATO ASI Series (1985 and 1989). The present NATO-INSERM workshop has focused specifically on a group of silicates, named phyllosilicates because of their sheet structure, of which health related effects have been poorly and sporadically investigated. These silicates are presently largely used as filling materials (kaolin, talc, chlorite), insulating materials (vermiculite, micas), adsorbants (sepiolite, attapulgite) and in many other industrial applications. The estimated annual world production is presently 5.5 million tons of talc (1.8 million for Europe) and only in the United Kingdom about 3.5 million tons of kaolin.

Major structural features are used in this study to reconstruct the links which existed between North America, Europe and Africa before the opening of the North Atlantic Ocean. The synthesis of geophysical and geochemical data as well as geological observations allows the recognition of the original geometry of the Grenvillian, Cadomian, Caledonian, Ligerian-Acadian and Hercynian foldbelts and the identification of ancient plate sutures. The reader will find a wealth of information based not only on the English but also on the French and Spanish literature, thus opening less known results to the international community.

Scientists who have had the opportunity of being associated with Professor Egon T. Degens, to whom this Festschrift is devoted, have been influenced by his ideas on subjects as varied as: extraterrestrial organic matter, origin of life, evolution of organisms, isotope biogeochemistry down to more imminent ones such as the carbon cycle and its implications on climate. This variety is also reflected in the papers in the present volume contributed by colleagues who have known Egon or have worked with him. Egon Theodor Degens was born on April 16, 1928 at Inden, Germany and had his education in Bonn and Wiirzburg. After a stint at the Pennsylvania State University he returned to Wiirzburg to help set up one of the first organic geochemistry laboratories in the world. This laboratory was the breeding ground for some of the eminent organic geochemists at work today. Later, he joined the California Institute of Technology and began his work on stable carbon isotopes, and later on biogeochemical compounds in natural waters. From California he moved on to the east coast, which led to yet another productive phase at the Woods Hole Oceanographic Institution. He was instrumental in the pioneering work carried out by the Woods Hole scientists in the Black Sea which is the largest anoxic basin in the world, and in the Red Sea where the first hydrothermal ore deposits on the seafloor were discovered.

The fundamental principles of tephrochronology were de- veloped in Iceland through the classic research of Professor Sigurdur Thorarinsson in the 1940's and 1950's. By his studies on the volcanic ash layers (tephra) produced by the historic explosive eruptions of the volcano Hekla, he established that individual tephra layers could be correlated over large areas of Iceland. As the deposition of such layers was essentially instantaneous on a geological time-scale, the tephra layers provided a distinctive and widespread isochronous stratigraphic marker. Since Thorarinsson's pioneering work, the study of tephra has become a powerful and increasingly important research tool in many branches of the geological sciences and related disciplines. In response to the recent rapid growth and diversifica- tion of tephra studies we decided to coordinate a NATO Advanced Studies Institute under the auspices of the INQUA Commission on Tephra. The ASI, entitled "Tephra Studies as a Tool in Quaternary Research," was held from June 18th to June 29th, 1980, at Laugarvatn in Iceland. This book represents the proceedings of that Institute and is the first book dedicated to tephra studies, its many uses and applications. The subject matter combines disciplines as diverse as Quaternary strati- graphy, isotope geochronology, petrology, deep-sea geology, volcanology, volcanic hazards mapping, archaeology and ecology in one volume, and illustrates both present uses and future potential of tephra research.