1 The content ofthis article is based on a German book version ) which appeared at the end of the year 1986. The author tried to incorporate - as far as possible - new important results published in the last year. But the literature in the field of "convection and inhomogeneities in crystal growth from the melt" has increased so much in the meantime that the reader and the collegues should make allowance for any incompleteness, also in the case that their important contributions have not been cited. This could for example hold for problems related to the Czochralski growth. But especially for this topic the reader may be refered to the forthcoming volume of this series, which contains special contributions on "Surface Tension Driven Flow in Crystal Growth Melts" by D. Schwabe and on "Convection in Czochralski Melts" by M. Mihelcic, W. Uelhoff, H. Wenzl and K. Wingerath. The preparation of this manuscript has been supported by several women whose help is gratefully acknowledged by the autor: Mrs. Gisela Neuner for the type writing, Mrs. Abigail Sanders, Mrs. Fiona Eels and especially Prof. Nancy Haegel for their help in questions of the English language and Mrs. Christa Weber for reading corrections. Also the good cooperation with the Springer Verlag, especially Mrs. Bohlen and with the managing editor of Crystals, Prof. H. C. Freyhardt, who critically read the manuscript, is acknowledged.

Time is a major factor in Quaternary science. Without a trustworthy chronometer any interpretation of changes in proxy data of stratigraphical origin is on weak ground. In fact, any attempt at a sound reconstruction of timing and rates of past climatic change as well as the response of the biosphere can only be achieved on the basis of a reliable chronology. Moreover, all correlations and comparisons through time on a continental or global scale depend heavily on the reliability of the time-scale used. Therefore the establishment of an absolute time-scale is a fundamental goal. In this contribution we refer to the term "absolute time-scale" as a time-scale consisting of ages determined on the basis of sidereal years. Traditional stratigraphical methods of absolute dating include the Swedish glacial varve chronology, already developed early in this century by De Geer (1912) and since then continuously improved (e.g. Stromberg 1985; Cato 1987). Unfortunately, however, a spatial correlation with other stratigraphies outside Fennoscandia is difficult.

The reserves, or extractable fraction, of the fuel-mineral endowment are sufficient to supply the bulk of the world's energy requirements for the immediately forseeable future-well into the next century according to even the most pessimistic predictions. But increasingly sophisticated exploration concepts and technology must be employed to maintain and, if possible, add to the reserve base. Most of the world's fuel-mineral resources are in sedimentary rocks. Any procedure or concept that helps describe, under stand, and predict the external geometry and internal attributes of major sedimentary units can therefore contribute to discovery and recovery of coal, uranium, and petroleum. While conceding the desirability of renewable and nonpolluting energy supply from gravitational, wind, or solar sources, the widespread deployment of these systems lies far in the future-thus the continued commercial emphasis on conventional nonrenewable fuel mineral resources, even though their relative significance will fluctuate with time. For example, a decade ago the progilostications for uranium were uniformly optimistic. But in the early 1980s the uranium picture is quite sombre, although unlikely to remain permanently depressed. Whether uranium soars to the heights of early expectations remains to be seen. Problems of waste disposal and public acceptance persist. Fusion reactors may ultimately eliminate the need for uranium in power generation, but for the next few decades there will be continued demand for uranium to fuel existing power plants and those that come on stream. This book is, to some extent, a hybrid."

Archaean Geochemistry 1972 - 1984 The realisation that the continental crust contains well-preserved relics which date as far back as 4/5 of the Earth's age has given a great impetus to the study of early Precambrian terrains. As late as the mid-sixties the Archaean still constituted the 'terra-in cognita' of earth science. High metamorphic grades, poor out crop, and not least a widely assumed obliteration of early crustal records by convective recycling and thermal reworking had com bined to discourage research in this field. Many excellent local studies existed, notably around gold mining centres, but remained unrelated to a broader regional and theoretical understanding. This situation has changed as the consequence of two inter-related factors: (1) advances in isotopic methods and their application to Precambrian rocks, and (2) the recognition that some of the oldest terrains have retained a wealth of primary igneous and sedi mentary textures and even geochemical characteristics."

Drilling deep into the earth holds a fascination for earth scientists derived in part from the fact that the drill hole is the ultimate test of a hypothesis. When surface exploration methods have been fully uti lized and all the geological inferences drawn about the structure be neath the surface, we must finally drill to sample directly the third dimension of the crust of the earth. The drill is thus the tool of choice of the energy and minerals re sources industry. Because of high cost, drilling has been only sparing ly used for solving fundamental problems in the earth sciences. But now, having used the quite sophisticated methodology of exploration geophysics, the exciting structural detail emerging from seismic re flection profiling in particular has led several nations to begin a major program of scientific drilling to solve some of the major prGb lems in the earth sciences. Hhat is described in this volume are the blueprints for national re search programs in France, the Federal Republic of Germany, Japan and the United States. The Soviet Union has already embarked on a major drilling effort, the results of which are soon to be published. Results, of course, are still few, and this first volume is more concerned with the problems to be solved."

Copper belongs to those metals whose concentrations in nature arise from a broad diversity of endogeneous and exogeneous pro- cesses, which applies to essentially all genetic classes of ore deposits. This is the first proceedings volume on copper metallogeny to cover the worldwide distribution of the four main groups of cop- per deposits, including in Part I: copper-nickel deposits with cobalt and platinum group elements; Part II: copper-molybde- num-gold deposits with silver, zinc, and lead; Part III/IV: copper- zinc-lead deposits (with silver etc.). On the occasion of the 27th International Geological Congress in Moscow, USSR, a symposium on copper metallogeny was held, dealing with metallogenesis and mineral deposits. The symposium was organized and sponsored by three international societies en- gaged in the field of ore deposits: The Society of Economic Geol- ogy (SEG), the Society of Geology Applied to Mineral Deposits (SGA) and the International Association on the Genesis of Ore Deposits (IAGOD). Invited papers were presented in four ses- sions: (1) Copper deposits in mafic and ultramafic complexes, (2) Porphyry copper deposits, (3) Copper deposits of volcanic-hydro- thermal association, and (4) Sediment-hosted copper deposits. The sessions were chaired by A. D. Genkin, A. J. Naldrett, J. D. Ridge and G. I. Gorbunov; V.1. Sotnikov, A. Soregaroli, R. H. Sillitoe and V. A. Evstrakhin; F. M. Vokes, A.1. Krivtsov, M. Solomon and N. I. Eremin; G. H. Friedrich, Yu. V. Bogdanov, A.C. Brown and F.P. Krendelev.

This book is intended primarily for exploration geologists and post graduate students attending specialist courses in mineral exploration. Exploration geologists are engaged not only in the search for new mineral deposits, but also in the extension and re-assessment of existing ones. To succeed in these tasks, the exploration geologist is required to be a "generalist" of the Earth sciences rather than a specialist. The exploration geologist needs to be familiar with most aspects of the geology of ore deposits, and detailed knowledge as well as experience play an all important role in the successful exploration for mineral commodities. In order to achieve this, it is essential that the exploration geologist be up to date with the latest developments in the evolution of concepts and ideas in the Earth sciences. This is no easy task, as thousands of publications appear every year in an ever increasing number of journals, periodicals and books. For this reason it is also difficult, at times, to locate appropriate references on a particular mineral deposit type, although this problem is alleviated by the existence of large bibliographic data bases of geological records, abstracts and papers on computers. During my teaching to explorationists and, indeed, during my years of work as an explorationist, the necessity of having a text dealing with the fundamental aspects of hydrothermal mineral deposits has always been compelling. Metallic mineral deposits can be categorised into three great families, namely: (I) magmatic; (2) sedimentary and residual; (3) hydrothermal."

Few knowledgeable people would deny that the field of mineral exploration is facing some difficult times in the foreseeable future. Among the woes, we can cite a worldwide economic uneasiness reflected by sluggish and at times widely fluctuating metal prices, global financial uncertainties, and relentless pressures on costs despite a substantial slowing down of the rate of inflation. Furthermore, management is forced to tum to more sophisticated and expensive technologies and to look farther afield to more remote regions, as the better quality and more easily accessible ore deposits have now been revealed. This rather gloomy outlook should persuade explorationists to cast about for a new philosophy with which to guide mineral exploration through the challenging decades ahead. Once already, in the early 1960s, a call for change had been heard (Ref. 30 in Chapter 1), when it became obvious that the prospecting methods of yesteryear, so successful in the past, could not keep up with the rapidly growing demand for minerals of the postwar period. The answer, a massive introduction of sophisticated geophysical and geochemical technologies backed by new geo logical models, proved spectacularly successful throughout the 1960s and the 1970s. But for both economic and technological reasons, the brisk pace of the last two decades has considerably slowed down in the early 1980s, as if a new threshold has been reached."

The problem of time-and strata-bound formation of ore deposits has during the past decade become one of the most debated topics in cur rent international discussion. Due to the amazing results of modern mineral exploration and world-wide geophysical research, the mutual relationship between the complex geological history pf a crustal seg ment and the development of distinct metallogenic provinces (ore belts) has received much interest. Reviewing the earth's history in this light one can now recognize metallogenic epochs even of global range which document the existence of world-wide time-bound ore enrich ments. The knowledge of these metallogenetic processes has been growing step by step for several decades. It began with simple observations and sceptic interpretations, which at first threw heretical spot lights on to the edifices of the prevailing theories on granitic differentiation as the favoured source of ore deposits. It was obvious that the new ideas at first referred to ore enrichments in sedimentary sequences, nowadays summarized under the term strata-bound, and mainly interpreted as stratiform or sedimentary ore deposits. Moreover, the modern term "strata-bound" also includes ore mineralizations which are bound to distinct units of layered (intrusive or extrusive) igneous complexes as a general descriptive term without genetical restriction Albert Maucher is one of the representatives of the initial era who discussed these genetical questions critically in the decade before the 2nd World War."

Metals in the hydrological cycle represent a very broad subject covering all parts of the geological cycle. The present version of this book, therefore, would not have been possible without the comments and suggestions for improvement on draft ver- sions of the various chapters by a large number of colleagues. We wish to express our gratitude to: P.A. Cawse (AERE, UK), J.N. Galloway (University of Virginia, USA) and S.E. Lindberg (Oak Ridge National Labo- ratory, USA) for reviewing the chapter on atmospheric trace metals. G. Batley (CSIRO, Australia) and B.T. Hart (Chisholm In- stitute of Technology, Australia) for reviewing the chapter on speciation of dissolved metals. E.K. Duursma (Delta Institute, The Netherlands), J.M. Bewers and P.H. Yeats (Bedford Institute of Oceanography, Canada) and D. Eisma (Netherlands Institute for Sea Re- search, the Netherlands) for reviewing the chapter on estuaries. P. Baccini (EAWAG, Switzerland) and W. Davison (Fresh- water Biological Association, UK) for reviewing the chapter on lakes. E.T. Degens (University of Hamburg, W-Germany) for re- viewing the chapter on the oceans, and J.P. Al (Public Works Department, The Netherlands) for reviewing most of the indi- vidual chapters. Without the collaboration of these colleagues this book would not have been possible in its present form.

The preparation of a volume on this topic was undertaken with some hesitancy on my part because the ramifications of the mineralogy of apatite involve both bio logical and physical sciences in very elaborate ways. This hesitancy may have arisen in part from the realization that considerable skill would be required in order to extract the meaning from the thousands of papers that have appeared within the past twenty years; the task of attempting to extract and assemble the usable information seemed gigantic. Greatly adding to the difficulty was the fact that a considerable portion of these journal articles contain nothing of value and further confuse a most complex topic. Nevertheless, it was thought that some of my formal education in the bio logical sciences, which has been greatly extended and augmented during the past fifteen years, might be integrated with my more extensive education and experience in chemistry, crystallography, mineralogy, geology and physics in order to pro duce something that would relate to the mineral apatite and its extremely diverse occurences in nature. At the same time it seemed essential to point out some of the many important aspects in which this knowledge bears on geology, agriculture, chemical engineering, medicine and dentistry."

The idea for a book on anorthosites came to me in January of 1986 while returning to Houston after holiday festivities in Dallas. The original idea was a review paper on anorthosites, but by the time I reached Houston, the subject material I contemplated induding was obviously too extensive for a single paper. The Director of the Lunar and Planetary Institute, Kevin Burke, was receptive to the idea of a book, and suggested that I contact Peter Wyllie, who serves as Editor of the Springer-Verlag series Minerals and Rocks. This effort, which I originally expected would take about a year, has taken nearly 6. I have many excuses- indolence, moving to another continent, other commitments, etc.-but the basic truth is that writing a book is much larger an undertaking than can be anticipated. Many people are aware of this, and I was duly forewarned. . But why write a book on anorthosites? This is a very good question, which I have considered from many angles. One rationale can be expressed in terms of a comparison between anorthosite and basalt. A first-order understanding of basalt genesis has been extant for many years. By contrast, there is little agreement about the origin of anorthosite. There are good reasons for studying and writing about basalt: it is the most abundant rock type on the Earth's surface, and is also plentiful on the surfaces of the other terrestrial planets.

This book introduces aqueous geochemistry applied to geothermal systems. It is specifically designed for readers first entering into the world of geothermal energy from a variety of scientific and engineering backgrounds, and consequently is not intended to be the last word on geothermal chemistry. Instead it is intended to provide readers with sufficient background knowledge to permit them to subsequently understand more complex texts and scientific papers on geothermal energy. The book is structured into two parts. The first explains how geothermal fluids and their associated chemistry evolve, and shows how the chemistry of these fluids can be used to, deduce information about the resource. The second part concentrates on survey techniques explaining how these should be performed and the procedures which need to be adopted to ensure reliable sampling and analytical data are obtained. A geothermal system requires a heat source and a fluid which transfers the heat towards the surface. The fluid could be molten rock (magma) or water. This book concentrates on the chemistry of the water, or hydrothermal, systems. Consequently, magma-energy systems are not considered. Hot-dry rock (HDR) systems are similarly outside the scope of this text, principally because they contain no indigenous fluid for study. Both magma-energy and HDR systems have potential as energy sources but await technological developments before they can be exploited commercially. Geothermal systems based on water, however, are proven energy resources which have been successfully developed throughout the world.

33 14. 3. 5 REE between Plagioclase and Aqueous Fluid 0 Cullers et al. (1973) measured the distribution of REE at 850 C and 750 bars pressure between a natural plagioclase, An, and gaseous water. The rare earths 65 favored the plagioclase by a factor which varies from about 25 for Ce to 10 for Lu. Data were also obtained for forsterite, diopside, enstatite and two rhyolite glasses, on the one hand, and water on the other hand, thereby permitting estimation of the partition coefficients between all pairs of phases. 14. 4 Chemical Substitution in Natural Feldspars 14. 4. 1 Introduction It is quite impracticable to give all the data on chemical substitution in natural feldspars: indeed many of the details are significant only to some particular pegmatite or rock body. As far as possible, emphasis is placed on features of general interest to crystal chemists and to petrologists. Ironically the well established features can be described more easily than the uncertain ones, and unfortunately it is necessary to use valuable space on data of dubious value. The bibliography is fairly complete, but it was impracticable to locate all data, especially those in obscure journals. Each reference is followed by a list of the elements referred to in the paper, thereby permitting a reader to compile a fairly compre hensive set of references on any chosen element. Not all papers are mentioned in the text. The book on Geochemistry and Mineralogy of Rare Elements, etc."

Glass Chemistry is concerned with the relation of chemical composition, structure and properties of various glasses. The book has been translated from the third German edition, which serves as a textbook for university students in materials sciences and a reference book for scientists and engineers in glass science and production. The central themes of the book are the chemistry and physics of glass. Detailed knowledge of the compositional and structural facts is the basis for the systematic development of new glasses as construction and optical materials.
Glass Chemistry is an interdisciplinary book on the borderlines between chemistry, physics, mineralogy and even biology and medicine. The book represents a well balanced treatment for students, scientists and engineers.

New methods for the determination of the nature, proportion, and distribution of structural defects in microcrystallized lamellar systems are of utmost importance not only to experimentalists but also to theoreticians. Mathematical formalism - indispensable for such analyses - is well-illustrated by various examples, allowing this method to be easily adopted and even to be applied to other solids with lamellar or pseudo-lamellar structures.

Sandstone Petroleum Reservoirs presents an integrated, multidisciplinary approach to the geology of sandstone oil and gas reservoirs. Twenty-two case studies involving a variety of depositional settings, tectonic provinces, and burial/diagenetic histories emphasize depositional controls on reservoir architecture, petrophysical properties, and production performance. An introductory section provides perspective to the nature of reservoir characterization and highlights the important questions that future studies need to address. A "reservoir summary" following each case study aids the reader in gaining quick access to the main characteristics of each reservoir. This casebook is heavily illustrated, and most data have not been previously published. The intended audience comprises a broad range of practicing earth scientists, including petroleum geologists, geophysicists, and engineers. Readers will value the integration of geological versus engineering interests provided here, and will be enabled to improve exploration and production results.

together with contributions by invited geoscientists The Central Andes, whose orogenic activity is so impressively documented by recent volcanism and and counterparts from other countries, during a workshop held in Berlin, 23-25 May 1990. A great earthquakes, have always attracted the attention of geoscientists. This interest became even more accen number of the papers presented at this workshop are tuated since, a quarter of a century ago, Plate included in this volume. While most of the chapters Tectonics became the basis for the New Global refer regionally to the segment of the southern Andes Tectonics concept, in which this huge mountain range mentioned above, others treat general aspects or deal was the most spectacular example of an active conti with Andean regions farther south, thus showing not only that the structures of this mountain range can be nental margin. Thus, in addition to the continuing research work by South American and foreign geo followed to more distant parts but also that there are scientists dedicated mostly to regional and economic significant structural variations along strike. problems, a great number of special research pro Like other books which originate from workshops grammes were initiated aiming at a better understand and are comprised of contributions from many ing of the processes acting at a convergent plate authors, also this one cannot give a complete and margin. well-balanced view of the scientific subject dealt In 1982, the earth science institutes of the Freie with, in this case the southern Central Andes.

In October 1986 the German Minister for Research and Technology (Bundesminister fUr Forschung und Technologie), Dr. H. Riesenhuber, officially announced that the super-deep borehole of the Continental Deep Drilling Program of the Federal Republic of Germany (KTB) would be drilled in the Oberpfalz area of Northern Bavaria. The site selection was based on a recommendation from the Deutsche Forschungsgemeinschaft (DFG) made after an evaluation by the Project Management of the technical and financial risks involved. This decision was preceded by a conference held from September 19 to 21, 1986 in Seeheim/Odenwald at which the results of the site studies in the Oberpfalz and the Schwarzwald were presented and thoroughly debated. The models and scientific targets resulting from these investigations formed the basis for a vote by the DFG Senate Commission for Geoscientific Interdisciplinary Research which was taken immediately after the conference. After evaluation of all scientific and technical aspects, the members of the commission voted almost unanimously for the Oberpfalz site. It was, ho",'ever, strongly emphasized that both locations had a wealth of attractive research objectives and that despite clear-cut differences in some major aspects scientifically the two could be regarded as more or less equivalent. Both'locations would be excellent sites for research drilling and would certainly cor.

Clay minerals form in a wide variety of crustal environments, e.g. in soil profiles, in sediments at the surface and in deeply buried sedimentary deposits, and under regional, contact and hydrothermal metamorphism conditions.
The book provides information about the dynamics of isotope systems in clays and helps us to understand the physical and chemical parameters in the transfer of masses within the crustal domain. Written for graduate students taking courses in sedimentary geochemistry, clay mineralogy, and soil mineralogy, the book will also appeal to scientists carrying out research on clay genesis and mass transfer in crustal environments.

" ... he who repeats a thing in the name of him who said it brings deliverance to the world ... " Mishnah, Sayings of the Fathers 6; 6 Main Objectives The present book intends to fulfill a number of purposes, which are arranged under the following scheme: 1. A topical review of main subjects in fractography, that branch of science which analyses fracture surface morphology and related features and their causes and mechanisms in technological materials. Among the materials that bear significant affinities to rock are in organic glass, ceramics, metals and polymer glass. 2. A historical review of the main studies published to date on rock fractography. In both these fields of review, one is confronted by the similarities between small-scale (micro metre) and large-scale (tens of metres) fracture surface morphologies. The similarities, on the one hand, and the differences on the other must surely promote further development of fractographical approaches in structural geology, where extrapola tion from microfractography to large-scale fractography is virtually a directive. As geologists become more familiar with the fractography of rocks, they undoubtedly will become aware of the great power of this descriptive discipline as a tool, in both qualitative and quantitative analysis. Rock fractography must yet be routinely applied in the structural analysis of rock formations in which fracture morphology is sufficiently prominent or extensive."

With the rapid development of fast processors, the power of a mini-super computer now exists in a lap-top box. Quite sophisticated techniques are be coming accessible to geoscientists, thus making disciplinary boundaries fade. Chemists and physicists are no longer shying away from computational mineral ogical and material science problems "too complicated to handle." Geoscientists are willing to delve into quantitative physico-chemical methods and open those "black boxes" they had shunned for several decades but with which had learned to live. I am proud to present yet another volume in this series which is designed to break the disciplinary boundaries and bring the geoscientists closer to their chemist and physicist colleagues in achieving a common goal. This volume is the result of an international collaboration among many physical geochemists (chemists, physicists, and geologists) aiming to understand the nature of material. The book has one common theme: namely, how to determine quantitatively through theory the physico-chemical parameters of the state of a solid or fluid."

The present book is devoted to the study of the deep Earth's interior structure, one of the most important problems of Earth sciences today. The drilling of the Kola superdeep well inaugurated a new stage in the study of the Precambrian continental crust. The well was sunk in the northeastern part of the Baltic Shield, in an area where the Precambrian ore-bearing structures, typical of the ancient platform basements, are in juxtaposition with each other. To the present the well has been drilled to a depth of 12 km, has traversed the full thickness of the Proterozoic complex and a considerable part of the Archean stratum, and is still be ing worked on. This book reviews the principal results of investigations to a depth of 11,600 m; these are described in three sections: geology, geophysics, and drilling. The book begins with a general review of the history, the present state of knowledge, and trends of further investigations in the field of study of the Earth's interior and superdeep drilling. The first section of the book considers the geology of the vicinity of the Kola superdeep well and describes its geological section based on a detailed examination both of the cores and the near-borehole area."

The decision of Springer-Verlag to publish this book in English came as a pleasant surprise. The fact is that I started writing the first version of the book back in 1978. I wished to attract attention to potentialities inherent in selected-area electron diffraction (SAED) which, for various reasons, were not being put to use. By that time, I had at my disposal certain structural data on natural and synthetic minerals obtained using SAED and high-resolution electron microscopy (HREM), and this stimulated my writing this book. There were several aspects concerning these data that I wished to emphasize. First, it was mostly new and understudied minerals that possess the peculiar structural features studied by SAED and HREM. This could interest mineralogists, crystallo chemists, and crystallographers. Second, the results obtained indi cated that, under certain conditions, SAED could be an effective, and sometimes the only possible, method for structure analysis of minerals. This inference was of primary importance, since fine dispersion and poor crystallinity of numerous natural and synthe tic minerals makes their structure study by conventional diffrac tion methods hardly possible. Third, it was demonstrated that in many cases X-ray powder diffraction analysis of dispersed miner als ought to be combined with SAED and local energy dispersion analysis. This was important, since researchers in structural min eralogy quite often ignored, and still ignore even the simplest in formation which is readily available from geometrical analysis of SAED patterns obtained from microcrystals."

The principal aim of the present work is to understand the evolution of halogenesis in the Paleozoic. To succeed in the study it was neces- sary to make a general and systematic synthesis of data available on world-wide Paleozoic halogenic deposits and describe all known eva- porite basins. This study succeeds the monograph Paleozoic Salt For- mations of the World (Zharkov 1974a). The history of Paleozoic salt accumulation is based chiefly on evidence presented in the above monograph; this work should be considered as its direct continutation. The present work mainly aims at: (1) establishment of the num- ber of both salt and sulfate basins and salt and sulfate sequences formed therein in the Paleozoic; (2) determination of the stratigraphic position of salt and sulfate sequences in separate regions, their distant correlation and recognition of stages of evaporite sedimentation during the Paleozoic; (3) determination of the volume and areas of distribution of halite, potash, and sulfate sedimentation within basins and on continents through periods, epochs, and ages of the Paleozoic to single out epochs of the most intense evaporite sedimentation; (4) reconstruction of paleogeography of continents to recognize stages of evaporite accumulation and paleoclimatic zones of halogenic sedi- mentation in the Paleozoic; (5) understanding the evolution of eva- porite sedimentation in the Paleozoic. The nomenclature used in the book should be explained.