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."

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.

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

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

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.

The Advanced Science Institute on which this publication is based took the somewhat unusual form of a geological field symposium held during late August 1984. It was designed to demonstrate to experienced earth scientists from the North Atlantic area the full range of geological phenomena encountered in the British Caledonian rocks. The ASl travelled from South Wales to the far northwest of Scotland by the route shown on the map and in doing so examined sedimentary, igneous and metamorphic rocks from Pembrokeshire (Dyfed), Cardigan (Ceridigian), Snowdonia, Anglesey, the English Lake District and the Southern Uplands and Highlands of Scotland. Thus the fifty or so participants in the ASl studied the geological history and major structures of rocks exposed on either side of the supposed Lower Palaeozoic Iapetus Ocean the British sector of which closed to the south of the present Southern Uplands. Wales (1-5) afforded insight into the nature of the late Precambrian basement of England and Wales and the relationship of sedimentary and volcanic cover sequences to this basement. The Ordovician sequence in Wales is a sample of the volcanic rocks typical of a marginal basin, and were examined in Pembrokeshire and Snowdonia. The English Lake District (6) displays rocks from an island arc also of Ordovician age.

1.1. HISTORICAL DEVELOPMENT OF THE OPHIOLITE CONCEPT. Ophiolite, Greek for 'the snake stone', appears to have received its first written definition by Brongniart (1813) as a serpentine matrix containing various minerals. Later in 1821 and 1827, Brongniart determined that volcanic and gabbroic rocks were also present, associated with cherts, and he ascribed an igneous origin to the ophiolite. Amstutz (1980) gives an excellent exegesis of these early contributions and traces the further use of the term and concept of ophiolite. This concept had been forged in the western Alps and Apennines where, thanks to talented Italian geologists, in particular A. Sismonda, B. Gastaldi, V. Novarese and S. Franchi, the study on metamorphic ophiolites (the 'pietre verdi') has rapidly progressed. At the tum of the century the association of radiolarite, diabase, gabbro (euphotide), and serpentinite-peridotite was clearly identified, even through their metamorphic transformations. In 1902, Franchi developed the hypothesis introduced earlier by Lotti (1886), of a submarine outflow to explain the 'pietre verdi' association, on the basis of the attribution of the variolites and metamorphic prasinites to an hypabyssal volcanism, also responsible for the formation of radiolarites. Thus, before the popular work of Steinmann in 1927, the various components constituting an ophiolite had been identified and its hypabyssal origin proposed. As recalled by Amstutz (1980), the so-called 'Steinmann trinity', which consists of the association of radiolarites, diabases and serpentinites, was more completely and better defined in these earlier works.

work on structural and stratigraphic relationships is presented from various parts of the mountain belt. In the first paper of the section, R. O. Greiling (Heidelberg) describes the Middle Allochthon of Vasterbotten, northern Sweden, where tectonic windows through the Upper Allochthon (Seve Nappe) show that the Middle Allochthon has a similar lithostratigraphy to that of the Stalon Nappe Complex of the eastern Caledonian margin but with a more ductile deformation and metamorphosed to a higher grade following thrust emplacement. These relations are explained by suggesting that the window rocks were initially subducted beneath a colliding western plate but were later accreted to the base of the western plate and thrust with it. The thrust geometry of the windows, described as antiformal stacks, agrees with this model. The Middle Allochthon of the Caledonian margin in northern Sweden is described by R. O. Greiling and R. Kumpulainen (Heidelberg and Stockholm) who record two distinct metasedimentary units separated by a thick zone of mylonites interpreted as a lateral thrust ramp. Turbidites in the northern unit were derived from an unidentified igneous source to the east and cannot be correlated with other sequences in the Middle Allochthon. In another paper dealing with the northern Swedish Caledonides, L. Hansen (Uppsala) describes down-to-the-west normal faults cutting the autochthonous Cambrian sediments in the tunnel sections of the Vietas Hydropower Station, but themselves being truncated by the basal decollement of the Lower Allochthon.

In recent years mineralogy has developed even stronger links with solid-state chemistry and physics and these developments have been accompanied by a trend towards further quantification in the theoretical as well as the experimental aspects of the subject. The importance of solid-state chemistry to mineralogy was reflected in a symposium held at the 1982 Annual Congress of The Royal Society of Chemistry at which the original versions of most of the contributions to this book were presented. The meeting brought together chemists, geologists and mineralogists all of whom were interested in the application of modern spectroscopic techniques to the study of bonding in minerals. The interdisci plinary nature of the symposium enabled a beneficial exchange of information from the various fields and it was felt that a book presenting reviews of the key areas of the subject would be a useful addition to both the chemical and mineralogical literature. The field of study which is commonly termed the 'physics and chemistry of minerals' has itself developed very rapidly over recent years. Such rapid development has resulted in many chemists, geologists, geochemists and mineralogists being less familiar than they might wish with the techniques currently available. Central to this field is an understanding of chemical bonding or 'electronic structure' in minerals which has been developed both theoretically and by the use of spectroscopic techniques."

The fourth volume in this series consists of eleven chapters. The first five deal with more theoretical aspects of the kinetics and mechanisms of meta morphic reactions, and the next six consider the interdependence of defor mation and metamorphism. All papers deal with natural processes that inter act on various time scales and with different degrees of mass and heat transfer. Consequently, many fundamental axioms of metamorphic petrol ogy and structural geology are questioned both for their accuracy and their usefulness. In raising such questions, most contributors have pointed to ways in which the answers could be forthcoming from appropriate experi mental studies or observations on natural materials. In their discussion of how order/disorder can influence mineral assem blages, Carpenter and Putnis emphasize that metastable crystal growth is common in metamorphic systems and state' 'there may be some reluctance (among many earth scientists) to accept that significant departures from equilibrium could occur." On the basis of presented evidence, they question whether reactions ever occur close to an equilibrium boundary. The neces sity for pressure or temperature overstepping is also required by nucleation rate theory. In any case, the degree of order is severely influenced by these kinetic effects in igneous, sedimentary, and metamorphic environments."

Over 60% of the Earth's surface is covered with deep marine sediments, however, until the early 1980s, no comprehensive text books appeared to support the rapid expansion in the study of these sediments. While the whole field of marine geology has expanded enormously and entirely new disciplines, such as paleoceanography, have been developed, there remains a lack of reference texts on study techniques that investigators in the marine community can turn to. Minerals and Mineraloids in Marine Sediments is an optical identifica tion guide that I believe will become a standard reference text for use in the microscope analysis of marine sediment& and sedimentary rocks. The systematic collection of sediment cores from the deep ocean floor began in earnest with the Swedish Deep Sea Expedition, 1947-1948. Much of the microscopic examination of the sediments collected in these piston cores (10 m+ long) was conducted on separated grain mounts or thin sections of impregnated sediments. By the late 1960s a simpler technique of examining a mounted smear of the cored silt and clay size sediment on a microscope slide had become standard practice in American oceanographic institutions. This semi quantitative technique became the standard tool used in core description aboard Glomar Challenger through the 15 years of the Deep Sea Drilling Project (DSDP), 1968-1983. Visual percentage estimates of biogenic and mineral components were made using petrologic micro scopes."

Statistical evaluations of exploration data are the basis for decisions to be made at various stages of an exploration project. In contrast to other geostatistical books, Statistical Evaluations in Exploration for Mineral Deposits focuses not only on theory, but examples are also given, frequently originating from experience in mineral exploration by the author who worked worldwide for a mining company. Together with its companion volume, Economic Evaluations in Exploration, the book illustrates methods used in exploration campaigns and mining activities. It is intended as a vademecum for geologists who are forced to make quick decisions regarding an exploration project. It also addresses scientists and students involved in teaching or in mineral economic evaluations, recommendations or decisions.

This book represents the proceedings of the 9th written by a very active group of physicists at Kongsberg seminar, held at the Norwegian Mining the University of Oslo - physicists interested in Museum located in the city of Kongsberg about complex systems in general and geo-like systems 70 km Southwest of Oslo. The Kongsberg district in particular. is known for numerous Permian vein deposits of The content of the book is organized into three native silver, and mining activity in the area lasted major parts following the introductory chapter. for more than 300 years, finally ceasing in 1957. Chapters 2 to 7 primarily treat the role of fluids The previous eight Kongsberg seminars were in specific geological environments, ranging from focused on ore-forming processes and all of these sedimentary basins (Chapters 2-3) to contact were organized by Professor Arne Bj0rlykke, now metamorphic/hydrothermal scenarios (Chapters director of the Norwegian Geological Survey. 4-5) and regional metamorphic settings (Chapters Since process-orientated research tends to break 6-7). The following four chapters (8-11) focus down the traditional barriers between the different on various properties of fluid-rock systems that geological disciplines, this seminar has always are critical in controlling flow and transport been a meeting point for people with a variety through rocks. These include: mineral solubility of geological backgrounds.

This book has been prepared by the collaborative effort of two somewhat separate technical groups: the researchers at the Institute for Petroleum and Organic Geochemistry, Forschungszentrum Jii lich (KFA), and the technical staff of Integrated Exploration Systems (IES). One of us, Donald R. Baker, from Rice University, Houston, has spent so much time at KFA as a guest scientist and researcher that it is most appropriate for him to contribute to the book. During its more than 20-year history the KFA group has made numerous and significant contributions to the understanding of petroleum evolution. The KFA researchers have emphasized both the field and laboratory approaches to such important problems as source rock recognition and evaluation, oil and gas generation, maturation of organic matter, expulsion and migration of hydrocarbons, and crude oil composition and alteration. IES Jiilich has been a leader in the development and application of numerical simulation (basin modeling) procedures. The cooperation between the two groups has resulted in a very fruitful synergy effect both in the development of modeling software and in its application. The purpose of the present volume developed out of the 1994 publication by the American Association of Petroleum Geologists of a collection of individually authored papers entitled The Petroleum System - From Source to Trap, edited by L. B. Magoon and W. G. Dow."

Identificationof rock-forming minerals in thin section is a key skill needed by all earth science students and practising geologists. This translation of the completely revised and updated German second edition (by Leonore Hoke, Institute of Geological and Nuclear Sciences, New Zealand) provides a comprehensive guide to identifying 140 of the most important rock-forming mineral species. The book is divided into three main parts. Part A is a practical guide to the fundamentals of crystal optics, polarization microscopy and the practical use of microscopes. Part B gives a detailed description of the characteristic optical features, special features, and the paragenesis of the most common rock-forming minerals. This well-illustrated part is divided into opaque minerals, isotropic, uniaxial and optical biaxial mineral groups. Part C contains identification tables for the minerals and diagrams showing the international classification of magmatic rocks, as well as a colour plate section showing crystal forms of minerals. The book will provide an invaluable guide to all undergraduate earth scientists, as well as to professional geologists requiring an overview of mineral identification in thin section.

This book consists of a collection of papers presented at the NATO Advanced Research Workshop (ARW) on "Crust/mantle Recycl ing at Convergence Zones," held in Antalya, Turkey, between May 25 to 29, 1987. The workshop was attended by 36 earth scientists from ten countries and 28 papers were presented. Crust/mantle recycling is one of the most fundamental processes in the Earth. The study and understanding of this process requires the consideration of the Earth as a whole system including the atmosphere, the hydrosphere and the core, as well as the crust and the mantle; effective interdisciplinary collaboration is therefore essential to our progress. The Antalya ARW gave us the opportunity to assemble key specialists from relevant branches of the earth sciences and to address our state of knowledge. This ARW proved to be very useful in attaining an interdisciplinary, mutual understanding among specialists from diverse fields such as isotope and trace element geochemistry, mineral physics, theoretical geophysics, seismology, experimental petrology, and structural geology.

The collection of papers in this volume is a direct result of the Society of Economic Paleontologists and Mineralogists Research Symposium on "Thermal History of Sedimentary Basins: Methods and Case Histories" held as part of the American Association of Petroleum Geologists Annual Convention in New Orleans in March 1985. The original goal of the sym posium was to provide a forum where specialists from a variety of dis ciplines could present their views of methods that can be used to study the thermal history of a sedimentary basin or an important portion of a basin. An explicit part of that goal was to illustrate each method by presentation of a case history application. The original goal is addressed by the chapters in this volume, each of which emphasizes a somewhat different approach and gives field data in one way or another to illustrate the practical useful ness ofthe method. The significance of our relative ignorance of the thermal conductivities of sedimentary rocks, especially shales, in efforts to understand or model sedimentary basin thermal histories and maturation levels is a major thrust of the chapter by Blackwell and Steele. Creaney focuses on variations in kerogen composition in source rocks of different depositional environments and the degree to which these chem- . ically distinct kerogens respond differently to progressive burial heating."

We have used in Vol.2 the same structural scheme similar they are organized alphabetically, just for as used in Vol. 1. convenience in consulting.The alphabetical order We used as the list of minerals the reference is provisional, it is not an important aspect of the book Mineral Reference Manual by Nickel and classification, and willtend to disappear. Nichols, edited by Van Nostrand Reinhold, New In Vol. 1 some condensed model sheets were York, 1991, and we first organized the minerals by presented to illustrate the simplicityof the patterns chemical formulas, from the simpler to the more of the packing layers of the A, AmB and ApBqC n r complex (Tables 73 to 172), as presented on page close-packed minerals (Tables lL to 17Lof Vol.1). 1of Vol.1.The results of the structural studywere The aim was to stimulate the complete systematic ordered by structural formulas (Tables 27S to derivation of the simple mineral close-packed 59S). Then we summarized the classified structure structures, as was tried by the author (Lima-de- types (not including the tentatively classified) in Faria (1965) Zeit. Krist., 122, 359-374). In Vol. 2 Tables 60S to 61S. Finally we presented some the layers are more complex and the correspond- global results (Tables 62S and 63S). ing condensed models sheets were not included. In certain cases the general chemical and the The reader should refer to the book Structural structural formulas may be difficult to compare.

Acknowledgements xix pioneering workers on igneous layering in Greenland xx Wbrkshop participants xxii Henning Sfl!rensen, University of Copenhagen, Dermark. Latte Melchior Larsen, Geological SUrvey of Greenland, Copenhagen, Dermark. Abstract 1 1 * Introduction 1 1. 1 The agpaitic rocks of the Ilimaussaq intrusion 3 2. Igneous layering in the Ilimaussaq intrusion 4 3. Mineralogy of the layered kakortokite series 15 4. Chemistry of the layered kakortokite series 19 5. Origin of the kakortokite layering 20 5. 1 Discussion 22 6. Conclusion 25 References 26 2. I. AYERn";r CCMPl\CTIOO NID PCBJ. "--MN}tATIC ~ IN '!HE KLOKKEN INTRUSIOO 29 Ian Parsons and SUsanne M. Becker, University of Aberdeen, U. K. Abstract 29 1. Introduction 30 2. Age of the intrusion 31 3. General structure and mineral variation 31 vi TABLE OF CONTENTS 3. 1 Nomenclature of rock types 31 3. 2 Bulk chemical and modal variation 36 4. The contacts and wall-rocks 37 4. 1 Guter contact 37 4. 2 The gabbro sheath 37 4. 3 The unlaminated syenite sheath 39 4. 4 The gabbro-syenite transition 41 5. The layered series 43 5. 1 General relationships 43 5. 2 Granular syenites 43 5. 2. 1 Structure and cryptic variation 43 5. 2. 2 Origin of granular layers 46 5. 2. 3 Trace elements and chamber dlinensions 47 5. 3 Laminated syenites 48 5. 3. 1 General features 48 5. 3. 2 Mineral layering 51 5. 3.

During the past few years there has been a marked increase in the use of advanced chemical methods in studies of soil and clay mineral systems, but only a relatively small number of soil and clay scientists have become intimately associ ated and acquainted with these new techniques. Perhaps the most important obstacles to technology transfer in this area are: 1) many soil and clay chemists have had insufficient opportunities to explore in depth the working principles of more recent spectroscopic developments, and therefore are unable to exploit the vast wealth of information that is available through the application of such ad vanced technology to soil chemical research; and 2) the necessary equipment gen erally is unavailable unless collaborative projects are undertaken with chemists and physicists who already have the instruments. The objective of the NATO Advanced Study Institute held at the University of Illinois from July 23 to August 4, 1979, was to partially alleviate these obstacles. This volume, which is an extensively edited and reviewed version of the proceedings of that Advanced Study Institute, is an essential aspect of that purpose. Herein are summarized the theory and most current applications of six different spectroscopic methods to soil and/or clay mineral systems. The instrumental methods examined are Mossbauer, neutron scattering, x-ray photoelectron (XPS, ESCA), nuclear magnetic resonance (NMR), electron spin resonance (ESR, EPR), and photoacoustic spectroscopy. Contributing authors were also lecturers at the Advanced Study Institute, and are each well known and respected authorities in their respective disciplines."

After the spectacular successes of the 1960's and 1970's, the mineral exploration business is at a crossroads, facing uncertain t: imes in the decades ahead. This situation requires a re-thinking of the philosophy guiding mineral exploration if it is to emulate its recent performance. The ma: i. n argument of a previous volume titled "Designing Opt: lmal Strategies for Mineral Exploration," published in 1985 by Plenum Publishing Corporation of New York, is that a possible answer to the challenge facing mineral explorationists lies in the philosophy of opt: irn1zation. This new approach should help exploration staff make the best achievable use of the sophisticated and costly technology which is presently available for the detection of ore deposits. The main emphasis of the present volume is placed on the mathematical and computational aspects of the opt: irn1zation of mineral exploration. The seven chapters making up the ma: i. n body of the book are devoted to the description and application of various types of computerized geomathematical models which underpin the optimization of the mineral exploration sequence. The topics covered include: (a) the opt: lmal selection of ore deposit types and regions of search, as well as prospecting areas within the regions (Chapters 2, 3, 4, 6), (b) the designing of airborne and ground field programs for the opt: lmal coverage of prospecting areas (Chapters 2, 3, 4), (c) delineation and evaluation of exploration targets within prospecting areas by means of opt: irn1zed models (Chapter 5).

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.

Mine Safety combines detailed information on safety in mining with methods and mathematics that can be used to preserve human life.

By compiling various recent research results and data into one volume, Mine Safety eliminates the need to consult many diverse sources in order to obtain vital information. Chapters cover a broad range of topics, including: human factors and error in mine safety, mining equipment safety, safety in offshore industry and programmable electronic mining system safety.

They are written in such a manner that the reader requires no previous knowledge to understand their contents. Examples and solutions are given at appropriate places, and there are numerous problems to test the reader's comprehension.

Mine Safety will prove useful for many individuals, including engineering and safety professionals working in the mining industry, researchers, instructors, and undergraduate and graduate students in the field of mining engineering.

Granite petrology has achieved significant progress since Tuttle and Bowen (1958) wrote the monograph on the Origin of granite in the light of experimental studies in the system NaAISi308-KAISi308-SiOrH20. Since then, the compo nents CaAI Si 0, FeO, MgO, and excess alumina have 2 2 s been added to the pure system Ab-Or-Qz-H 0 in order to 2 include plagioclase and common mafic minerals in the inves tigations. In addition to synthetic systems, natural rocks have been used as starting materials, and other fluid compo or substituted for water. nents have been added to There are many new data concerning properties of melts and magmas, dehydration melting of synthetic and natural rocks, and phase relationships at H 0-undersaturated con 2 ditions. We found it useful and necessary to summarize the available information in this volume, and an effort has been made to present up-to-date data on various aspects of gran ite petrology. Most parts of the manuscript were reviewed by John Clemens, Peter Nabelek, and Alan White. Their friendly help and suggestions improved it considerably. Some chap ters of this volume benefited from critical review by William Brown, Bruno Scaillet, and Robert Linnen. Peter Wyllie pro vided us with reprints and many critical and useful sugges tions. Jagmohan Singh improved the English considerably."

Many geologists have an equivocal attitude to fluid movements within the crust and the associated changes in the chemical and physical properties of crustal rocks. The controversies earlier this centuary between the "soaks" and the "pontiffs" memorably summarised by H. H. Read (1957) in The Granite Controversy have largely been resolved. Few would now advocate the formation of large granitic bodies by in situ transformation of pre-existing crust as the result of the passage of ichors without the formation of a granitic melt. To many geochemists fluid transport and metasomatism have become slightly suspect processes which at the most locally disturb the primary geochemical and isotopic signatures. While there is common agreement that there are marked differences in the composition of the lower and upper crust, the role of fluid movement as one of the controls of this differentiation is often neglected in favour of suggested primary differences in the composition of igneous rocks emplaced at different depths. Selective fluid transport however provides many geologists with their livelyhood. Without the secondary concentration of commercially important elements by fluids within the crust the mining industry, geological science and human activities based on their products would be very different.