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.

When an area of research is in fast growth, it often happens that no one single journal is to be found where most of the relevant publications are contained. Such is the case of the physics of intercalation compounds, a field which, by sitting at a corner point between materials science, solid state physics, and chemistry, finds its contributions largely scattered about in the literature. Given these circumstances it is of crucial interest to find a place where the most recent contributions and up-to-date referen ces can be found at once. For intercalated graphite and other similar com pounds this role has been played so far by proceedings of international con ferences, such as La Napoule (1977), Nijmegen (1979), Provincetown (1980), and Sendai (1980). The present book is an ideal continuation of this series, as it contains most of the invited and contributed papers of the Trieste International Con ference on the Physics of Intercalation Compounds, held in Trieste, Italy during the week 6-10 July 1981. The main emphasis is on intercalated graphite, though several interesting contributions deal with other materials, such as polyacetylene and transition metal compounds, or with general problems, such as two-dimensional melting. The book is divided into six sections-Structure and General Properties, Electronic Porperties, Stability and Phonons, Ordering and Phase Transitions, Magnetic Resonance, and Transport Properties-reflecting the main areas of interest, and also broadly the main discussion sessions of the Conference."

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.

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.

The role played by earth sciences in the scientific community has changed considerably during this century. Since the revolutionary discoveries of global processes such as plate tectonics, there has been an increasing awareness of just how fundamental many of the mechanisms which dominate in these processes depend on the physical properties of the materials of which the earth is made. One of the prime objectives of mineral sciences is now to understand and predict these properties in a truly quantitative manner. The macroscopic properties which are of most immediate interest in this context fall within the conventional definitions of thermodynamics, magnetism, elasticity, dielectric susceptibilities, conductivity etc. These properties reflect the microscopic contributions, at an atomistic level, of harmonic and anharmonic lattice vibrations, ionic and electronic transport as well as a great variety of ordering and clustering phenomena. The advances made by solid state physicists and chemists in defining the underlying phenomena lnvolved in the thermal evolution of materials have stimulated major new research initiatives within the Earth Sciences. Earth Scientists have combined to form active groups within the wider community of solid state and materials scientists working towards a better understanding of those physical processes which govern not only the behaviour of simple model compounds but also that of complex materials like minerals. Concomitant with this change in direction has come an increasing awareness of the need to use the typical working tools of other disciplines.

Water is the most effective agent in the climate system to modulate energy transfer by radiative processes, through its exchanges of latent heat and within cascades of chemical processes. It is the source of all life on earth, and once convective clouds are formed, it enables large vertical transports of momentum, heat and various atmospheric constituents up to levels above the tropical tropopause. Water triggers very complex processes at the earth's continental surfaces and within the oceans. At last, water in its gaseous phase is the most important greenhouse-gas! Numerical modelling and measurements of the state of the present climate system needs a very thorough understanding of all these processes and their various interactions and forcings. This is a prerequisite for more substantial forecasts of future states in all scales of time, from days to centuries. Therefore, the management of the World Climate Research Programme established in 1988 the new programme GEWEX (Global Energy and Water Cycle Experiment). GEWEX is specifically defined to determine the energy and water transports in the fast components of the climate system with the presently available modelling and measurement means and to provide new capabilities for the future. Research in GEWEX must further develop methods to determine the influence of climatic anomalies on available water resources.

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.

Nowadays, major environmental issues are the object of large public debates de- spite the fact that scientific knowledge is often insufficient to draw unequivocal conclusions. Such is the case in the ongoing debate regarding the specific contri- butions of anthropogenic greenhouse gas emissions and of natural climate changes to global warming. At least 10 to 20 years of additional observations will be re- quired, before we will be able to conclude, with certainty, on this subject. In the mean time, and as directed by their immediate interests, people will continue to promote contradictory opinions. The media are, in part, responsible for perpetuat- ing such debates in that they convey indiscriminately the opinion of highly credi- ble scientists as that of dogmatic researchers, the latter, unfortunately too often expressing working hypotheses as established facts. Naturally, in a similarly mis- informed manner, pressure groups tend to support the researcher whose opinions most closely represent either their particular ideological battles or their economic interests and, hence, in their own way, add further to the confusion and obscurity of the debate. Only a few years ago, mercury (Hg)contamination in hydroelectric reservoirs was the object of such media and social biases. At the time, analytical data used to support the discourse were themselves uncertain and numerous hypotheses, often times fanciful, were proposed and hastily "delivered" to the public.

This book originally appeared in German in 1974, under the title "Bergschadenkunde" (mining subsidence engineering), and then in Russian in 1978, published by Nedra of Moscow. When the German edition was almost out of print, Springer-Verlag decided to bring out a new edition, this time in English. For this English version the text has been thoroughly revised, enlarged, and sup plemented by over 100 new figures. The book deals with the current state of international knowl edge on strata and ground movement over mine workings, with its damaging effects on mine shafts and the land surface, and with measures for regulating mining damage in law and reducing it in practice. Discussion begins with the mine excavation underground - the cause - and ends with the damage to surface structure- the effect. Methods of roof control, including the subject of rock bursts, are not discussed, since that is a field concerned more with the safety of underground workings than with minimizing damage at the surface. Of the 500 literature references in the German edi tion, only the more important for an international readership have been retained, but no value judgement on the many pUblica tions not mentioned should be read into this. The book is principally intended as a working aid for the mine surveyor, the mining engineer, the architect, and the civil engineer. For the student and the post-graduate researcher, it of fers a summary and guide to this whole field of knowledge."

This collection of papers is based on a symposium held in 1987 at the Interna tional Union of Geology and Geodesy Congress in Vancouver, British Colum bia. The Symposium was planned as a follow-up to a session at the 1984 Geo logical Society of America Annual Meeting in Reno, Nevada, which dealt with the emplacement of silicic lava domes. In both cases, emphasis was placed on the physical and mechanical rather than chemical aspects of lava flow. The IUGG Symposium consisted of two lecture sessions, a poster session, and two discussion periods, and had 22 participants. The contributions to this volume are all based on papers presented in the various parts of the Sym posium. The motivation for studying lava flow mechanics is both practical and scientific. Scientists and government agencies seek to more effectively predict the hazards associated with active lavas. Recovering mineral resources found in lava flows and domes also requires an understanding of their emplacement. From a more theoretical standpoint, petrologists view lava studies as a way to directly observe the rheologic consequences of mixing crystals, bubbles, and solid blocks of country rock with silicate liquids. This information can then be used to constrain processes occurring in the concealed conduits, dikes, and chambers that feed flows and domes on the surface."

At last geochemists are offered one comprehensive reference book which gives the Eh-pH diagrams for 75 elements found in the earth's surface environment, including transuranic and other radioactive species. For each of these newly calculated diagrams short explanatory texts are added. For the first time the primary elements are considered in water with metal, sulfur, carbon, and other species as appropriate. Furthermore, based on these figures and up-to-date thermodynamic data presented in this reference, researchers can predict the behavior of elements in the surface environment. Geoscientists, chemists and environmental agencies will also benefit from several brief texts on the importance of various elements to problems of radioactive waste disposal.

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 . . . . . . . . . . . . . . . . . . . . . . . . ."

will probably be clarified by the continued cooperative efforts of scientists such as those in the group that met in Berlin last September. The staff of Dahlem Konferenzen is responsible for making the meeting of this group memorably pleasant and pleasantly mem- orable. Dr. Bernhard's gifts of charm, organizational skill, and administrative toughness assured that the conference was run elegantly, smoothly, and decisively, even down to the choice of editors for this volume. Marie Cervantes-Waldmann performed minor miracles extracting manuscripts gently but persistently from the authors and in turning the typescripts into a book. The other staff members of Dahlem Konferenzen were unfailingly helpful even under trying circumstances. They will be well rememberedbyall who were fortunate enough to be asked to Berlin for the first week in September, 1980. Mineral Deposits and the Evolution of the Biosphere, eds. H. D. Holland and M. Schidlowski, pp. 5-30. Dahlem Konferenzen, 1982. Berl in, Heidelberg, New York: Springer-Verlag. Microbial Processes in the Sulfur Cycle Through Time H. G. TrUper Institut f. Microbiologie, Rheinische Friedrich-Wilhelms-Universitat, 5300 Bonn 1, F. R. Germany Abstract. Two microbial processes are involved in the sulfur cycle of the earth's biosphere: anoxic dissimilatory sulfur oxidation by phototrophic bacteria and dissimilatory sulfate reduction by sulfate-reducing bacteria. In the presence of oxygen at chemoclines and redoxclines dissimilatory sulfur oxidation by chemolithotrophic bacteria (Thiobacillus, Beg- giatoa, and others) occurs. In addition, dissimilatory sulfur reducing bacteria participate in the sulfur cycle.

During the last thirty years profound developments in expe- rimental techniques to measure high temperature and pressu- res and thermodynamic properties of minerals have occurred. This technical development has been matched by an increased sophistication in applying theoretical methods to obtain new data or improve the quality of existing data. Using these newtechniques, Assessed Thermodynamic Data on Oxides and Silicates represents the successful attempt of the authors to develop an internally systematized data base which satis- fies the constraints of calorimetric measurements, phase equilibrium data, measured thermophysical properties of a phase, and heat capacities and entropies estimated from lat- tice vibrational models.

In these days of information explosion and high-cost publishing, it is perhaps only reasonable for an author to convince the reading public that it is getting something worth reading. After all, intense research into the upper mantle over the past two decades has already resulted in a number of volumes on kim berlites and their xenoliths. So why yet another one? First, in this book I have concentrated on kimberlite as an individual rock-type and a sampler of the upper mantle, in the hope of complementing such monographs as Deep seated inclusions in kimberlites and the problem of the composition of the upper mantle by N. V. Sobolev and Geologie du Diamant by M. G. Bardet, which have concentrated more on specific aspects of kimberlite and upper mantle geology; as a result I have not attempted to describe diamond prospecting and mining and, although I have attempted to give some of the up-to-date views on xenolith petrology, the confines of space have not permitted me to explore the complexities of the upper mantle as deeply as has Sobolev. Second, the literature is vast and I have tried to pull together for the reader the wide range of views and infor mation presented both in the recent geological literature and in recent multi-author volumes such as the Proceedings Vol umes of the two International Conferences on Kimberlite held at Capetown in 1973 and Santa Fe in 1977."

Papers presented at a Symposium held in Utrecht, The Netherlands, October 1982

On February 19, 1973, five centuries have elapsed since the birth of Nicolaus Coperni cus - the greatest astronomer of the Renaissance period - who rediscovered for us the heliocentric model of the solar system, and documented it by his life's work in such a manner as to make its concept a permanent property of mankind. The life of Copernicus, extending from 19 February 1473 to his death on 24 May 1543, was not too rich in adventures or biographical facts. Born in Toruti from a family of Polish burghers, he received his first university training in Cracow between 1491-1494. From Cracow he proceeded to Italy to spend the years between 1496-1503 at the Universities of Bologna, Padua and Ferrara - with occasional visits to Rom- in preparation for an ecclesiastical career. When Bishop Watzenrode - his patron and maternal uncle - could no longer extend his leave, Copernicus returned to Poland in 1503 to enter the service of the church establishment, which soon led to a canonry at the Frombork (Frauenburg) Cathedral in Warmia. And there - in the northern mists not far from the Baltic shores - in a land so different in climate from the sunny Italy of his youth - he was destined to spend the rest of his life."

Basic magmatic rocks make up approximately three-quarters of the crust ofthe present day Earth. Because we can observe and study the volcanic products of present day tectonic regimes comprehensively, we can shed light on ancient tectono-magmatic provinces, and thereby deduce the petrogenesis and evolution of the oldest basic rocks. This is the primary objective of this book. The book was conceived in order to provide a comprehensive review of the basic rocks produced during the first half of the Precambrian, i.e. the Archaean and early Proterozoic, to about 1.8 Ga years ago. Two major questions are addressed. First, what basic magmas were generated during the early Precambrian: were these magmas globally uniform, and to what extent were prevailing tectonic controls and compo sitions analogous to those of the present day? Clearly, this can be answered only by bringing together fundamental information about all relevant basic magmatic events. Second, is there any systematic temporal variation in the nature of basic suites, and what implications might such variations have on our interpretations of early Earth history? Are there important differences between early Archaean, late Archaean, Proterozoic and modern basic magmatic suites? The book uses two approaches to address these questions. Early chapters examine the fundamental characteristics of these basic rocks, whilst later chapters assess regional distribution and development by providing an overview of each major early Precambrian craton."

The main aim of this paper is to present some new and general results, ap plicable to the the equations of two phase flow, as formulated in geothermal reservoir engineering. Two phase regions are important in many geothermal reservoirs, especially at depths of order several hundred metres, where ris ing, essentially isothermal single phase liquid first begins to boil. The fluid then continues to rise, with its temperature and pressure closely following the saturation (boiling) curve appropriate to the fluid composition. Perhaps the two most interesting theoretical aspects of the (idealised) two phase flow equations in geothermal reservoir engineering are that firstly, only one component (water) is involved; and secondly, that the densities of the two phases are so different. This has led to the approximation of ignoring capillary pressure. The main aim of this paper is to analyse some of the consequences of this assumption, especially in relation to saturation changes within a uniform porous medium. A general analytic treatment of three dimensional flow is considered. Pre viously, three dimensional modelling in geothermal reservoirs have relied on numerical simulators. In contrast, most of the past analytic work has been restricted to one dimensional examples."

In the first edition of this book, we observed that it had been created to fill a need for a usable "self-contained volume on hydrodynamics" (and hydrogeology) that was written specifically for the petroleum industry, but could also serve the earth science community in general. When the first edition was published (1982), M. K. Hubbert, the father of petroleum hydrodynamics, was approaching the final stages of his very productive career. For this reason, the book served as a vehicle to amplify his concepts and spread and stimulate applications of some of his theories and methods throughout the exploration sectors of the petroleum industry. This was accomplished by blending discussions of Hubbert's concepts with some of the procedures used by industry specialists to answer practical oil and gas questions. The simple aim of the book was to bring this material to the fingertips of working geologists and geophysicists, who were "evaluating the hydrocarbon possibilities in larger exploration regions or assessing the potential of small, local subsurface oil and gas prospects. " It was also hoped that by treating areas of conceptual overlap between petroleum geology and ground water hydrology, workers in both disciplines would be brought into closer contact, resulting in mutual benefits gained through healthy scientific and technical interaction. This remains our objective in the second edition, although it has become apparent that additional material is needed to satisfactorily achieve it. The size of this volume reflects the new subject matter.

The papers in this volume are dedicated to Professor Dr. Dr. h.c. G. Christian Amstutz by his colleagues, friends, and students on the occasion of his 60th anniversary. The authors of this book - the theme was restricted to syngenesis and epigenesis in the formation of mineral deposits - wish to honour with their articles a scientist who has contributed to, and substantially promoted the understanding of the genesis of mineral deposits in the last decades. The majority of the articles deal with strata-bound depos its, thus reflecting one of his main scientific interests. In the tradition of his professors, Paul Niggli and Paul Ramdohr, G.C. Amstutz has maintained an open and active interest in many fields of earth science. His numerous papers have triggered a remarkable number of new ideas and investigations in a variety of fields, and the "happy marriage" of economic geology with sedimentology is cer tainly one of his main successes, starting with the first Symposium on Sedimentology and Ore Genesis at the Sixth International Sedimentological Congress at Delft in 1963."

Clays and soils are of great importance in various scientific fields, such as agriculture and environmental science, and in mineral deposits. Students and close collaborators of Georges Millot, the eminent French clay sedimentologist, have put together a book with topics ranging from weathering processes and diagenetic evalution of sediments to sedimentary mineral deposits. The book is of interest to practitioners, advanced students as well as teachers in the above fields.

In the extensive field of earth sciences, with its many subdisciplines, the trans fer of knowledge is primarily established via personal communication, during meetings, by reading journal articles, or by consulting books. Because more information is available than can be assimilated, it is necessary for the individual to search selectively. Books take more time from the inception of an idea until publication than any of the other means of communication men tioned. As a consequence, their function is somewhat different. Many good books are a compilation of up to date knowledge and serve as reference or instruction manuals. Some books are a collection of previously published papers dealing with a certain topic, while others may basically provide large sets of data or examples. The Frontiers in Sedimentary Geology series was established both for stu dents and practicing earth scientists who wish to either stay abreast of the most recent ideas or developments or to become familiar with an important topic in the field of sedimentary geology. The series attempts to deal with sub jects that are in the forefront of both scientific and economic interest. The treatment of a subject in an individual volume should be a combination of topi cal, regional, and interdisciplinary approaches. Although these three terms can be defined separately, in reality they should flow into each other. A topical treatment should relate to a major category of sedimentary geology.