Earth scientists, who have worked together for 6 years in the priority pro gram "Hydrogeochemical Processes in the Hydrological Cycle Within the Unsaturated and Saturated Zones," have summarized the results of their research in this volume. This is the occasion to take stock and then look ahead. The priority program was set up by the Senate of The Deutsche Forschungsgemeinschaft in October 1981. This was preceded by lengthy and careful preparation by a Program Committee, and was finally recom mended by the Senate Commission for Joint Research in Earth Sciences. The main aim was the interdisciplinary research of geochemical processes in natural systems in the total underground water cycle, whereby water pollution was not to be considered. Officially started on 1 September 1982, the program has received a grant of DM 10. 9 Mio. from the DFG, and this has enabled it to support a total of 50 projects. Although at the beginning, practice-oriented projects, which were funded elsewhere, were not to be included, many of the results are applicable. The four categories presented were investigated with vary ing intensity. An early concentration on certain representative fields of measurement and research areas proved to be the right approach - this avoided a waste of effort in other fields. During the period of the priority program, new and topical questions arose, e. g."

It seems almost trite to introduce this book by saying that man has been exploiting the intertidal zone for food for a long time. Just how long nobody knows for sure but the prehistoric inhabitants of Terra Amata, on the Mediterranean coast near Nice, ate marine intertidal animals at least 300 000 years ago. Similar impressive evidence, going back to at least 100000 years, exists for prehistoric man's consumption of intertidal animals along the South African coast. However, early man's dependence on intertidal resources probably goes back much further in time. During the last 2 million or so years temperate Eurasia experienced some 20 glaciations interspersed by warm equable periods. Different modes of life were open to man in colonizing the northern temperate zone. One was to become a "big-game" hunter, specializing, for example, on mammoths, the other to exploit marine intertidal resources. Of the two, probably the shoreline offered an easier environment for an original scavenging food-gatherer.

This book presents the results of the Third International Symposium on Observation of the Continental Crust through Drilling held in Mora and Orsa, Sweden, September 7 - 10, 1987. Volume 2 reviews new and general information on geology, geophysics, rock mechanics, geochemistry, drilling techniques and drilling problems in very deep holes of the FRG, USA and the Soviet Union. The proceedings are invaluable for earth scientists as well as for exploiters of geoenergy and other natural resources in the crust. Volume 1 summarizes the results of the Deep Gas Project in the Siljan impact structure, Sweden, including papers dealing with general aspects of astroblemes. It is of interest to all researchers working in the drilling industry and those interested in the problem of "deep gas."

In May of 1991, Victor Van Buren, who was then with Springer Verlag in New York City, asked us for timely topics in the earth sciences that would be appropriate for publication as a book. We all quickly agreed that recent interest and research activity on the role of organic acids in geological processes would make a timely book on this diverse and controversial topic. As coeditors, we outlined chapter topics for such a book that maintained a good balance between geological and geochemical interests. Specific authors were then sought for each of the chapter topics. We had exceptional success in getting leading researchers as authors, and their response was universally enthusiastic. This approach has been most gratifying in that it provides a cohesion and conciseness that is not always present in books representing compilations of papers from symposia. This book does not resolve the controver sies that exist regarding the significance of organic acids in geolog ical processes. However, it does present both sides of the controver sies in terms of available data and current interpretations. Readers may judge for themselves and envisage research necessary to resolve these controversies in the future. We thank the authors of this book for their participation, dedication, and cooperation. We are also grateful for support from Dr. Wolfgang Engel and his staff at Springer-Verlag (Heidelberg) in expediting the editing and publication of this book in a timely manner."

More than seventeen years have passed now since Glauco Gottardi and Ermano Galli 1 have published their remarkable book on "NATURAL ZEOLITES" where properties and features of naturally occuring phases then available have been compiled. Several new natural zeolites have been found since then, but also natural counterparts ofzeolites which have only been known as synthesis products. The natural formation conditions of zeolites could only be deduced and estimated from their geological environment at the time when NATURAL ZEOLITES has been published, as zeolite synthesis was mainly focused on procedures at low pressures such as those introduced by Barrer and co workers'. Natural zeolites, however, had only been obtained "occasionally" and systematic study to reconstruct these formation conditions has not been performed ever since. This book is focused on the synthesis of natural zeolites by simulating the natural synthesis conditions in the laboratory which are essentially different in means and results from those obtained by conventional synthesis methods. Although the synthesis in the laboratory has undoubtly a great number of advantages over nature such as the employment of proper precursors or the choice of pressure and temperature in a wide range, the synthesis time is very limited in respect to natural conditions: synthesis times ofyears or even tens ofyears which would be necessary to obtain synthesis results for some zeolites- e.g. at 4 DegreesC (deep sea conditions) are rather unrealistic.

One of the fundamental objectives of physical geochemistry is to understand the evolution of geochemical systems from microscopic to regional and global scales. At present there seems to be a general recognition of the fact that internal properties of minerals record important aspects of the evolutionary history of their host rocks which may be unraveled by very fine scale observations. A major focus in the development of geochemical research in the last thirty years has been the application of classical thermodynamics to reconstruct the conditions at which the states of quenched mineralogical properties of rocks have equilibrated during the course of their evolution. While these works have funda mentally influenced our understanding ofthe physico-chemical history ofrocks, in recent years petrologists, mineralogists, and geochemists have been making greater efforts towards the application of kinetic theories in order to develop a better appreciation of the temporal details of geochemical processes. The present volume brings together a variety of current research on transport in systems of geochemical interest from atomic to outcrop scales. A major theme is atomic migration or diffusion, and its various manifestations on microscopic and macroscopic scales. Transport in the solid state is controlled by diffusion and is responsible for the states of atomic ordering and relaxation of composi tional zoning in minerals, development of compositional zoning during cooling, exsolution lamellae, and creep."

The earth is seen as a dynamic body undergoing convection that is driven by its internal heat. The elucidation of the nature and evolution of the earth's lithosphere, that has provided all minerals and energy resources and the space in which we live is one of the principal motives behind the International Program "Dynamics and Evolution of the Lithosphere". A full understanding of the lithosphere requires further research especially on the continents and their margins: while the oceanic lithosphere cools and subsides as it flows away from the zone of upwelling, the continents, because of their different composition, remain buoyant in the mantle and survive over major portions of the earth's history. In trying to produce full confirmation of the validity of sea floor spreading and lithosphere subduction, Central Europe became more and more a crucial case. The deformation of continental plates is, however, more complex than that of the ocean-floor pattern. No discrete boundary exists between both the African and Eurasian plates. A number of unanswered questions arise e.g. whether African crust has overridden Europe, or European lithosphere collided in the ranges of Atlas of Algeria. The work of German, French and Suiss geologists accomplished much during this century. Central Europe has come to serve as a test site for the refinement of plate tectonics. A new understanding of the crustal dynamics of Central Europe was born with the aim of explaining its structural evolution.

Microbial mats are benthic communities of a variety of microorganisms. Their investigation requires multidisciplinary studies and close cooperation between microbiologists, biogeochemists, and geologists.
Reported here are recent advances in the study of structure, development and ecological relationships. The methodology described includes microsensors as well as new molecular techniques for the detection and identification of microorganisms. Increasing interest exists for applied aspects, e.g. the possibility to use natural or constructed microbial mats for the degradation of xenobiotics, for site remediation, etc.

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.