Only a few years ago, if you needed an appraisal of The revolution in the personal property appraisals gems and jewelry for any reason, you asked your local field (of which jewelry is a part) is a little more than a jeweler, who hastily scribbled a one-line handwritten decade old. There now exist uniform standards and note. He or she usually performed the appraisal for procedures for personal property appraisers, classes free, and did so with reluctance, accommodating you in valuation techniques, and degree programs in the only because as a customer you held the promise of a valuation sciences. future sale. The price your jeweler may have assigned Professional jewelry appraisers are on the edge of to the jewelry was granted without the least regard a new vocation. Banks, insurance companies, and for market research, legalities, or ethics. In most in governmental agencies have all helped bring about stances, the estimate was no more than a properly the changes and contribute to the birth of the profes completed sales receipt. sion; they have realized that they can demand and Gemologists were usually pushed into the role of get high standards of performance and integrity from appraiser by their jeweler employers, who were eager jewelry appraisers, as they can from appraisers of real to gain an advantage over their competitors by adver property."

As a method of structure analysis, electron diffraction has its own spe cial possibilities and advantages in comparison to the X -ray method for the study of finely dispersed minerals with layer or pseudolayer structures. How ever, possibly because of the prior existence of the X-ray method, which found universal application in different fields and attracted the main efforts of spe cialists, electron diffraction has been unevenly disseminated and developed in different countries. In particular, the oblique texture method, which gives very complete and detailed structural information, has been mainly used in the Soviet Union, where electron-diffraction cameras specially suited to the method have been constructed. In other countries, studies have been made of micro-single crystals, because these studies could be carried out with existing electron microscopes. It should be recognized that the scale of distribution and use attained by electron-diffraction methods, at present limited by exist ing experimental conditions. is more than justified by the value of the results which may be obtained by their aid. The author hopes that the present book will give the reader a fuller idea of the valuable advantages of the method, and of the structural crystallography picture which has been built up for clay minerals, and layer silicates in general, from electron-diffraction data. The time between the appearance of this book and that of the Russian edition has been comparatively short."

Cratons and Fold Belts of India, is a unique attempt at presenting geological characteristics and evolution of the fold belts and the cratonic areas of the Indian shield. The author has evaluated the different evolutionary models for each fold belt in light of all the currently available geological and geochronological informations that are clearly listed. Shortcomings, if any, of each model are stated and a viable geodynamic model is presented for each fold belt. The book is self-contained it includes an introduction to the processes of mountain building, especially plate tectonics theory with its application to the evolution of the Himalaya as an illustrative example so that the reader can better appreciate the novel approach to the evolution of Proterozoic fold belts. The author eschews a detailed account of the fold belts for a clear description of all the concepts that go into building models. It is primarily written for graduate students, teachers and for those geoscientists who aspire to know all about the Indian shield."

This monograph has its origins in a two-day meeting with the same title held in London, England in the spring of 1987. The idea for the meeting came from members of the UK Mineral and Rock Physics Group. It was held under the auspices of, and made possible by the generous support of, the Mineralogical Society of Great Britain and Ireland. Additional financial assistance was provided by ECC International pIc and the Cookson Group pIc. The aims of the London meeting were to survey the current state of knowledge about deformation processes in non-metallic materials and to bring together both experts and less experienced Earth scientists and ceramicists who normally had little contact but shared common interests in deformation mechanisms. This monograph has similar aims and, indeed, most of its authors were keynote speakers at the meeting. Consequently, most of the contributions contain a review element in addition to the presentation and discussion of new results. In adopting this format, the editors hope that the monograph will provide a valuable state-of-the-art sourcebook, both to active researchers and also to graduate students just starting in the relevant fields.

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."

This special publication no. 4 of the European Association of Petroleum Geoscientists and Engineers is devoted to some recent developments in the petroleum geology of France. Most of the papers have been presented either as oral or poster communications at the special session "Hydrocarbons of France" of the EAEG - EAPG Paris Conference (June, 92). A few additional papers have been added for their thematic interest, such as recent advances in sequence stratigraphy and structural geology applied to exploration of oil and gas in complex areas. Synthetic papers are also presented, covering most of the French sedimentary basins including a few oversea French agreements and territories.

Early in this century, the newly discovered x-ray diffraction by crystals made a complete change in crystallography and in the whole science of the atomic structure of matter, thus giving a new impetus to the development of solid-state physics. Crystallographic methods, pri marily x-ray diffraction analysis, penetrated into materials sciences, mol ecular physics, and chemistry, and also into many other branches of science. Later, electron and neutron diffraction structure analyses be came important since they not only complement x-ray data, but also supply new information on the atomic and the real structure of crystals. Electron microscopy and other modern methods of investigating mat ter-optical, electronic paramagnetic, nuclear magnetic, and other res onance techniques-yield a large amount of information on the atomic, electronic, and real crystal structures. Crystal physics has also undergone vigorous development. Many re markable phenomena have been discovered in crystals and then found various practical applications. Other important factors promoting the development of crystallog raphy were the elaboration of the theory of crystal growth (which brought crystallography closer to thermodynamics and physical chem istry) and the development of the various methods of growing synthetic crystals dictated by practical needs. Man-made crystals became increas ingly important for physical investigations, and they rapidly invaded technology. The production of synthetic crystals made a tremendous impact on the traditional branches: the mechanical treatment of mate rials, precision instrument making, and the jewelry industry.

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."

At attempt is made here to provide a comprehensive The Basement "massifs" roughly delimit the main account in book form of the Petroleum Geology of sedimentary areas of the: Nigeria, a country which in 1979 was the world's 1. ABAKALIKI, BENUE, GONGOLA AND YOLA sixth largest oil producer and rated the twelfth gIant TROUGHS petroleum province of the world by Ivanhoe (1980) 2. BIDA OR MIDDLE NIGER BASIN in terms of known recoverable resources (cumulatIve 3. SOKOTO EMBAYMENT OF THE IULLEM production + proven + probable reserves) of oil and MEDEN BASIN 4. BORNU-CHAD BASIN gas. . 5. DAHOMEY BASIN Nigeria, which has been an indepe. ndent sovereIgn country since 1960, faces the AtlantIc Ocean on the These basins and troughs, taken together with the south, is bounded by the Peoples' Republic of Benin onshore part of the Nigeria Delta Complex, occupy (ex-Dahomey) on the west, by the Republic of Niger about 178 000 square miles, half the total area of and by the Sahara on the north, the Republic of Chad Nigeria. Figure 3 shows the area of Nigeria in com on the northeast, and is bounded by the Umted Re parison to areas of other well known petroleum public of Cameroun on the east. It now consists of provinces and units, such as the Gulf. Coast of. the 19 states organized in a federation and, largely be United States, North Sea etc."

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.

Many people have contributed to the production of this book, and I wish to acknowledge the following colleagues who have, over the past 15 years, contributed much discussion, preprints, thin sections, rock samples, and unpublished and/or difficult-to- obtain information: Steve Bergman, Roger Clement, Howard Coopersmith, Barry Dawson, Alan Edgar, Tony Erlank, Steve Haggerty, Barry Hawthorne, Bram Janse, Viktoria Komilova, Sergei Kostrovitskii, Henry Meyer, Peter Nixon, Nick Rock, Mike Skinner, Patricia Sheahan, Simon Shee, Barbara Scott Smith, Andy Spriggs, Ken Tainton, Larry Taylor, Nikolai Vladykin, Allan Woolley, and Peter Wyllie. Special thanks go to Henry Meyer, for providing many hours of microprobe time at Purdue University, and to Mike Skinner, for samples and the opportunity to examine the Anglo-American Research Laboratory collection of orangeites. Particular thanks are expressed to Ken Tainton for permission to quote data from his Ph.D. thesis. Particular gratitude is expressed to Sam Spivak for drafting and photographic work and to Anne Hammond for preparing many polished thin sections of these difficult rocks. Their dedication, skills, and attention to detail are greatly appreciated by the author. Others from Lakehead University who helped materially during the production of this work include Reino Viitala (thin sections), Alan MacKenzie (electron microscopy), and Shelley Moogk-Pickard (trace element analysis). Carl Hager is thanked for assistance in using the Purdue microprobe.

Remarks by JVS. Volumes 1 and 2 of Feldspar Minerals were published in 1974, but Volume 3 was not completed because I was forced to devote 3 years to the resolution of unforeseen problems in the construction of an ion probe. By 1977, the incomplete draft for Volume 3 had become obsolete because of the enormous advances in knowledge of feldspars, particularly those in lunar rocks and meteorites, and in both deep-seated and ancient terrestrial rocks. Furthermore, it soon became obvious that a completely new version of Feldspar Minerals was needed because of the important new results on the physical and chemical properties. I had kept up with the interesting but tedious chore of weekly reading of the incoming literature and maintenance of the files. By 1980, the intense day-to day pressure had gone from my research programs on lunar rocks and on the development of the ion microprobe as a quantitative geochemical instrument, and I began preparation of a second edition of Feldspar Minerals."

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."

Key biogeochemical events in the ocean take place in less than a second, are studied in experiments lasting a few hours, and determine cycles that last over seasons or even years. Models of the controlling processes thus have to take into account these time scales. This book aims at achieving consensus among these controlling processes at all relevant time scales. It helps understand the global carbon cycle including the production and breakdown of solved organic matter and the production, sinking and breakdown of particles. The emphasis on considering all time scales in submodel formulation is new and of interest to all those working in global ocean models and related fields.

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.