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 Second International Symposium on Observation of the Continental Crust Through Drilling (supported by the Alfred Wegener Foundation, the Federal Ministry of Research and Technology, the German Research Society and the Inter-Union Commission on the Lithosphere) took place in Seeheim (Odenwald) and included a discussion on the Continental Deep Drilling Programme of the Federal Republic of Germany. This sym- posium was regarded as the continuation of a course agreed upon in Tarrytown in 1984. Here, the scientific contents and technical con- cepts of the technically complex and expensive experiments of conti- nental drillings were carefully coordinated before the national commit- tees carne to practical decisions. In Seeheim, rather than in Tarrytown, the methods of technical realization were in the foreground, as the results of scientific projects, e. g. , the NAGRA or the Salton Sea Scien* tific Drilling Project, were evaluated, supplementing industrial ultra- deep drilling experience. The presentation and discussion of the Con- tinental Deep Drilling Project of the Federal Republic of Germany was also granted ample scope with nine lectures and sixty posters. The con- tents of the KTB presentation have been summed up in two contributions and included in this volume. The conference centered on three major subjects: The National- Prograrrunes and Aspects of Geoscience: H. Vidal, FRG; H. Riesen- huber, FRG; E. Seibold, FRG; K. Fuchs, FRG; Cl. Megnien, F; R. S. An- drews, USA; F. G. Stehli, USA; E. A. Kozlovsky, USSR; E. V.

The Thirteenth International Conference on Basement Tectonics was held on the campus of Virginia Polytechnic Institute and State University in Blacksburg, Virginia from June 2 -6, 1997. The oral presentations and discussions over three days covered a wide range of topics, and provided the international audience with a perspective on scientific efforts underway around the world. The conference participants were able to attend two separate field trips: (I) a pre-conference trip guided by Professor Robert Hatcher of the University of Tennessee, Knoxville, examined the Basement rocks in the North Carolina -Tennessee region of the Appalachian Mountains, and (2) a mid-conference field trip guided by A.K. Sinha, convener of the conference, allowed participants to examine the complex rock associations and structures of the> 1000 m.y. old basement rocks in Virginia. Both the field trip guidebooks and abstract volumes were published for the conference. The meeting brought together scientists from more than 14 countries. Their participation, and the fiscal success of the meeting would not have been possible without the support of the Department of Geological Sciences, the College of Arts and Sciences (VPI&SU) and the Basement Tectonics Association. Their support is gratefully acknowledged. As Chairman of the Organizing Committee, I would like to thank Margie Sentelle, Jay Thomas, Peter Welch, and Barry Robinson for the smooth operation of the conference.

This book is written as a practical field manual to effective. Each geolOgist has to develop his/her be used by geologists engaged in mineral explo own techniques and will ultimately be judged on ration. It is also hoped that it will serve as a text results, not the process by which these results and reference for students in Applied Geology were reached. In mineral exploration, the only courses of universities and colleges. The book 'right' way of doing anything is the way that aims to outline some of the practical skills that locates ore in the quickest and most cost-effective turn the graduate geologist into an explo manner. It is preferable, however, for an individ rationist: . It is intended as a practical 'how to' ual to develop his/her own method of operation book, rather than as a text on geological or ore after having tried, and become aware of, those deposit theory. procedures which experience has shown to work An explorationist is a professional who search well and which are generally accepted in indus try as good exploration practice. es for ore bodies in a scientific and structured way. Although an awkward and artificial term, The chapters of the book approximately fol this is the only available word to describe the low the steps which a typical exploration pro totality of the skills which are needed to locate gramme would go through. In Chapter 1, the and define economic mineralization."

The present work. Authigenic Minerals in Sedimentary Rocks, is designed for the broad circle of lithologists, and also for the geologists and geochemists who are studying sedimentary rocks and ores. Its specific purpose is to stir up interest among lithologists and geologists in the geochemical environment associated with the formation of authigenic minerals in sedimentary rocks, to encourage work in tracing the sequence of formation of these min erals, and to direct attention to other genetic problems. The book by no means pretends to be a determinative atlas of the authigenic minerals in sedimentary rocks; its task is to draw the reader's attention to questions of origin and, at the same time, to equip him with systematic knowledge about the physical and, especially, the optical properties of these minerals. In addition, the simplified chemical reactions indicated in the book wiIl permit one to distinguish similar minerals, and will also allow him to detect various mineral deposits in the field. Another purpose of the book is to acquaint chemists and geochemists with the properties of the minerals they study in making chemical analyses, minerals that com monly occur as polymineralic aggregates in the samples that are examined."

Can a continuous growth of agriculture be achieved in the sub-Sahara region without inducing irreversible damage to the ecosystem? Until now, doubts have been expressed as to the actual capacity of the soils to sustain a desirable increase of production which can match the requirements of a fast-growing population. Thirty years of investigation and a renewed comprehensive interpretation of research data on soil fertility show that a sustainable agriculture growth could be a practical possibility in a savannah region.

The oceans cover about 72 percent of our planet (which is named for the remaining 28 percent). These oceans have fascinated and challenged the human race for centuries. In the past, the ocean had been used first as a source of food and later as a means of transportation. However, the oceans have recently become very important-they may offer a solution to many of our modern problems. For example, refuse from land is to be dumped into the ocean never to be seen again; fish and other biological resources are to be caught and used to meet the protein deficiency of the world; oil and gas from the continental shelf and perhaps deeper areas will eventually solve our energy problems. None ofthese examples is completely possible, and the at source offood and later as a means of transportation. However, the oceans social, and ecological problems in the marine environment. Countries are al ready planning how the oceans can be divided up, so that they will get their "fair share." Economists, politicians, and others are producing almost daily, optimistic or pessimistic views (depending upon your own viewpoint) about the ocean and its resources. Equally loud reports come from environ mentalists, conservationists, government sources, and oil companies con cerning the pollution and potential destruction of the ocean."

Zeolites, with their crystalline microporous structures, are cordial hosts to a wide variety of guests. However, it was the abrupt and unexpected departure of one of these guests (water) from a host (stilbite) on heating which led Cronstedt, in 1756, to coin the term "zeolite" (from the Greek meaning "boiling stone") to describe this material. Since that time, approximately 40 different naturally-occurring zeolites have been discovered on earth. Recent studies of meteorite compositions have shown that these guest-host materials (e. g. , sodalite) occur in other parts of the universe as well. However, it wasn't until the twentieth century that synthetic routes to zeolites and other non-aluminosilicate molecular sieves were discovered. In addition, with the development of X-ray diffraction and the various spectroscopies, better understanding of the nature of the cavities, cages, and channels of these materials has led to the industrial exploitation of their guest-host properties. The world of zeolites has now expanded into a greater than 2 billion pound per year business, with major applications in detergent formulations, catalysis, and as adsorbents and desiccants. Their economic impact is difficult to determine; however, the improvement in gasoline yields alone (from catalytic cracking) must account for hundreds ofbillions ofdollars in increased GDP. In this volume, we have brought together a sampling of recent developments in various areas of guest-host or inclusion chemistry in zeolites.

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.

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.

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.

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."

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.

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.

This book deals with the problems and methods of paleohydrogeolo gy in relation to ore deposit studies. It presents a description of dif ferent techniques used in the course of structural-paleohydrogeologi cal, paleo hydrogeochemical and paleo hydro geothermal investiga tions. It also provides itlformation on the regular, regional patterns of formation and subsequent distribution of ground water within dif ferent shells of the Earth. The main aspects of metal content of ground water and contemporary processes of ore genesis are discuss ed. Ore deposits are classified according to paleohydrogeological con ditions under which they were formed. The readers are acquainted with paleohydrogeological analysis of these conditions for different types of ore deposits, namely (1) ore deposits formed in artesian basins, in which sedimentary rocks were predominant both at the time of magmatic activity and in the periods free of this activity; (2) ore deposits formed in artesian, ad artesian basins (and admassifs) characterized by extensive development of volcanic rocks and magmatic activity; (3) ore deposits that originated in hydrogeological massifs (and admassifs) in the process of formation of linear weather ing crusts. This book, which should be of great interest to geologists engaged in prospecting for and exploration and study of ore minerals, also in cludes 38 tables, 60 illustrations and a bibliography of 450 titles. EVGENY A. BASKOV Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 The Science of Paleohydrogeology and Its Objectives in Ore Deposit Studies . . . . . . . . . . . . . . . . 4 2 Principal Distribution Patterns of Contemporary Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. 1 Notion of Hydrosphere . . . . . . . . . . . . . . . . . . . . . . . . ."

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.

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.

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.

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."

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 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 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.