This series of monographs represents continuation on an international basis of the previous series MINERALOGIE UNO PETROGRAPHIE IN EINZELOARSTELLUNGEN, published by Springer-Verlag. The voluminous results arising from recent progress in pure and applied re­ search increase the need for authoritative reviews but the standard scientific journals are unable to provide the space for them. By their very nature, text-books are unable to consider specific topics in depth and recent research met'hods and results often receive only cursory treat­ ment. Advanced reference volumes are usually too detailed except for experts in the field. It is often very expensive to purchase a symposium volume or an "Advances in . . . " volume for the sake of a specific review chapter surrounded by unrelated chapters. We hope that this monograph series will by-pass these problems in fulfilling the need. The purpose of the series is to publish, at reasonable prices, reviews and reports of care­ fully selected topics written by carefully selected authors, who are both good writers and experts in their scientific field. In general, the mono­ graphs will be concerned with the most recent research methods and results. The editors hope that the monographs will serve several functions, acting as supplements to existing text-books, guiding research workers, and providing the basis for advanced seminars. August 1967 W. VON ENGELHARDT, Tiibingen T. HAHN, Aachen R. Roy, University Park, Pa. J. W. WINCHESTER, Ann Arbor, Mich. P. J. WYLLIE, Chicago, Ill.

Zeolites form a family of minerals which have been known since the 18th century, but they remained a curiosity for scientists and collectors until 60 years ago, when their unique physicochemical properties attracted the attention of many researchers. In the past 30 years there has been an ex­ traordinary development in zeolite science; six International Conferences on Zeolites have been held every 3 years since 1967, and a large number of interesting contributions have been published in their proceedings. Many books, written either by individual authors or by several authors under a leading editor, have been published on these interesting silicate phases, but none has been devoted specifically to natural zeolites, even though this theme may be of interest not only to earth scientists, but also to chemists, as the in­ formation obtained from natural samples completes and in­ tegrates the characterization of many zeolites. We are trying to fill this gap on the basis of 20 years of research on natural zeolites, which we performed at the University of Modena together with many friends and colleagues. If it is in general difficult to write a scientific book with­ out upsetting somebody, this is particularly true for a book on natural crystals, because mineralogy is an interdisciplin­ ary science which covers some fields of physics, chemistry, it is almost impossible to meet every petrology, geology, and requirement.

Considerable progress has been made in our understanding of the physicochemical evolution of natural rocks through systematic analysis of the compositional properties and phase relations of their mineral assemblages. This book brings together concepts of classical thermodynamics, solution models, and atomic ordering and interactions that constitute a major basis of such analysis, with appropiate examples of application to subsolidus petrological problems. This book is written for an audience with a senior undergraduate level background in chemistry. Derivations of fundamental thermodynamic relations which are in need of reemphasis and clarification are presented.

This monograph was begun with two objectives in mind. The first was to provide a review of research involving the application of neodymium isotopic measurements to pro­ blems in earth science. In the process of organizing to do this, I realized that the research in this field had produced a need for an updated review of the underlying paradigms. This need had arisen because of the special properties of the samarium-neodymium isotopic system, and because the research had transgressed the traditional boundaries be­ tween the subfields of earth science. Without such a review, the significance of the results seemed likely to remain un­ necessarily obscure to interested scientists from related disciplines. Consequently, the second objective became the provision of a theoretical framework for the application of neodymium isotopic studies. Much of what this contains is not new, but it is drawn together here for the first time. At the time the writing was initiated, the literature of the field was still relatively limited. Over the past 5 years it has grown enormously. Considering the rate at which the writing progressed, it became clear that this could not be a fully up-to-date review and still reach completion. The selection of material for the review sections is biased toward earlier studies. Part I presents most of the background information.

There are several books emphasizing the mineralogical and petrological aspects of granites, but this book is the only one emphasizing the experimental aspects.

This series of monographs represents continuation on an inter­ nationai basis of the previous series MINERALOGIE UND PETRO­ GRAPHIE IN EINZELDARSTELLUNGEN, published by Sprin­ ger-Verlag. The voluminous results arising from recent progress in pure and applied research increase the need for authoritative reviews but the standard scientific journals are unable to provide the space for them. By their very nature, text-books are unable to consider specific topics in depth and recent research methods and results often receive only cursory treatment. Advanced reference volumes are usually too detailed except for experts in the field. It is often very expensive to purchase a symposium volume or an "Advances in . . " volume for the sake of a specific review chapter surrounded by unrelated chapters. We hope that this monograph series will by­ pass these problems in fulfilling the need. The purpose of the series is to publish reviews and reports of carefully selected topics written by carefully selected authors, who are both good writers and experts in their scientific field. In general, the monographs will be concerned with the most recent research methods and results. The editors hope that the monographs will serve several functions, acting as supple­ ments to existing text-books, guiding research workers, and providing the basis for advanced seminars. March 1971 W. VON ENGELHARDT, Tiibingen T. HAHN, Aachen R. Roy, University Park, Pa. J. W. WINCHESTER, Tallahassee, Fla. P. J. WYLLIE, Chicago, III. Contents 1 I. Introduction Sketch of Trollheimen 4 Acknowledgments . .

Professor OTTO BRAITSCH'S Entstehung und Stoffbestand der Salz- lagerstiitten has since its publication in 1962 enjoyed a reputation as the most complete and authoritative treatment, in any language, of the geochemistry of evaporites. The issue of this translation will now make it accessible to a much wider circle of readers. The years since first publica- tion of the German edition have seen a great surge of discussion and research on evaporites among English-speaking geologists, and while BRAITSCH'S work was important to some of these it can now no longer be ignored by any. It may be worth pointing out that, title notwithstanding, this volume takes as its subject not only the salts but all evaporite minerals and rocks, but that it makes no attempt to go beyond the geochemical evidence in discussing the origin of these evaporites. The reader should not expect to find here any extensive discussion of paleogeography and stratigraphy, or even petrographic detail. Within its scope of geochemistry and mineral- ogy the coverage is extensive.

Since the end of World War II isotope geology has grown into a diversi­ fied and complex discipline in the earth sciences. It has progressed by the efforts of a relatively small number of specialists, many of whom are physi­ cists, chemists, or mathematicians who were attracted to the earth sciences by the opportunity to measure and to interpret the isotopic compositions of certain chemical elements in geological materials. The phenomenal growth of isotope geology during the last 25 years is an impressive indi­ cation of the success of their efforts. We have now entered into a new phase of development of isotope geology which emphasizes the application of the new tools to the solution of specific problems in the earth and planetary sciences. This requires the active participation of a new breed of geologists who understand the nature and complexity of geological problems and can work toward their solution by a thoughtful application of the principles of isotope geology. It is there­ fore necessary to explain these principles to earth scientists at large to enable them to make use of the new information which isotope geology can offer them.

and their identification obviates individual thermochemical studies on every genus. The stability relations among sedimentary carbonate minerals are now more or less well known. The common rock-forming minerals cal­ cite and dolomite are indeed stable phases in the pertinent systems. Most other carbonate minerals of similar composition which are known to occur in the younger sediments are metastable with respect to calcite, dolomite, and magnesite. This implies that the sedimentation of carbon­ ates is determined only in part by stability relations. Kinetic factors, which allow the formation of metastable minerals, appear to be more important. Although the diagenetic transformations leading to stable minerals take place by virtue of thermodynamic requirements, the reac­ tions themselves are triggered by kinetic factors as well. Some of the reactions leading from metastable to stable carbonate assemblages are susceptible to simulation in the laboratory; others (e. g. dolomitization) appear to be so slow that they can be studied only in analogous systems characterized by reasonable reaction rates. In all attempts to explain the possible mechanisms of such reactions, we must consider the crystal structures of the final products as well as of the starting materials. This is another viewpoint from which mineralogy is important to carbonate petrology, if we regard the crystal chemistry of minerals as a part of mineralogy. A certain parallelism with clay mineralogy suggests itself.

This book represents the results of a lengthy study which Professor ALFRED RITTMANN began some thirty years ago. The relationship between the chemical and mineralogical composition of igneous rocks is established as far as is possible. Petrographers will appreciate that this problem is extremely complex, particularly since this relationship forms the basis of the classification and nomenclature of igneous rocks. The ingenious scheme of calculation of the CI.P.W. norm system is essentially chemical in nature. The compositions of the stoichiometrically ideal "normative minerals" do not correspond to those of the constituent minerals found in rocks. Although the "norm" is not intended to equal the "mode" or actual mineral composition of a rock, at least a qualitative agreement between the norm and the mode is desirable. For a number of rocks and rock groups, especially the leucocratic and silicic rocks, the deviation of the norm from the mode is generally within tolerable limits. For the melanocratic and highly subsilicic rocks, on the other hand, the CI.P. W. scheme of calculation too often yields results which fail to reflect the observed mineral composition. The anomalies produced in the cal­ culation of extremely subsilicic volcanic rocks have recently been briefly discussed by F. CHAVES and H. S. YODER, JR. (1971).

My goal in writing this book was to provide an introduction to meteorite science and a handbook on meteorite classification. Insofar as I succeeded it should prove useful both to the practicing professional and to university students at the upper-division and graduate levels. I originally intended the book to be nearly twice as long. The second half was to be a review of properties relating to the origin of each group of meteorites. Chapter XVIII is an example of how these later chapters would have looked, although most would not have been as interpretative. These chapters would have been useful chiefly to meteorite researchers looking for a quick summary of group properties; they were not written because of lack of time. Perhaps I will start to prepare this "second volume" in a year or so when my family and I have recovered from the preparation of the present volume. Although some parts of the classification portion are mildly icono­ clastic, I have attempted either to avoid the inclusion of speculative interpretations or to flag them with a caveat to the reader. I have relaxed these principles somewhat in Chapter XVIII to conserve space, but even there the discussion of alternative speculations should give the reader a feeling for the degree of uncertainty attached.

At first glance it may seem presumptuous to want to add yet another to the numerous books on Differential Thermal Analysis (DT A). Thermoanalytical methods have been in use for some time, as shown by the more than five thousand publications containing DT A or TG curves listed by SMOTHERS and CHIANG in the bibliography to their handbook and abstracted in the several volumes of Thermal Analysis Abstracts (TAA), edited by J. P. REDFERN for the International Con­ federation for Thermal Analysis (ICT A). Every three years the proceed­ ings of ICT A meetings are published, bringing the latest results of thermoanalytic research. There is also the Scifax DT A Data Index, edited by R. C. MACKENZIE (1962) and modeled on the ASTM pattern card index (used for X-ray investigations), a compilation of the DT A data for several hundred minerals, and inorganic and organic materials. The theoretical foundations of thermogravimetry and DT A have been described in detail by LEHMANN, DAS and PAETSCH (1953), R. C. MACKENZIE (1957, 1970), DUVAL (1963), WENDLANDT (1964), GARN (1965), F. PAULIK et al. (1966), SMOTHERS and CHIANG (1966), and KEATTCH (1969). Thermoanalytical results are strongly influenced by various factors relative to preparation and equipment (see 1-2. 4 of this study). This is the reason why we frequently find, in these books as well as in the Scifax-Card catalog, contradictory data on the same substance.

I was invited to write this book as part of the Minerals, Rocks and Organic Materials Series of Springer-Verlag by Professor Peter J. Wyllie in 1974. Ophiolites have preoccupied me ever since 1948 as a graduate student and up to the present time as part of my research with the U.S. Geological Survey. During this period ophiolite, an obscure European geological term, has attained an ever-increasing importance, is now used to include all fragments of ancient oceanic lithosphere incorporated into the orogenic zones of modern and ancient continental margins, and is a standard part of the plate tectonic paradigm. The purpose of this book is to provide a starting point for anyone interested in the background and state of knowledge concerning ophiolites (ancient oceanic lithosphere). Because ophiolites represent fragments of old oceanic crust their tectonic setting and age are extremely important in the reconstruction of ancient plate boundaries. Present­ day plate tectonic theories involve the generation and disposal of oceanic lithosphere, so that these ancient fragments of oceanic lithosphere can be used directly to reconstruct conditions within the ancient oceans. Since 1970, numerous meetings and conferences directly related to ophiolites have stimulated worldwide interest in the subject. As part of the International Correlation Program, the project "Ophiolites of Continents and Comparable Oceanic Rocks," was initiated by Dr. N. Bogdanov, Geological Institute, Moscow. This project has brought together an international group that has focused on the outstanding problems and is now producing a world map of ophiolite distribution.

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.

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.

Students of a phenomenon as common but complex as andesite genesis often are overwhelmed by, or overlook, the volume and diversity of relevant information. Thus there is need for periodic overview even in the absence of a dramatic breakthrough which "solves the andesite problem" and even though new ideas and data keep the issues in a state of flux. Thus I have summarized the subject through mid·1980 from my perspective to help clarify the long-standing problem and to identify profitable areas for future research. Overviews are more easily justified than achieved and there are fundamental differences of opinion concerning how to go about them. It is professionally dangerous and therefore uncom­ mon for single authors, especially those under 35 such as I, to summarize a broad, active field of science in book-length thor­ oughness. Review articles in journals, multi-authored books, or symposia proceedings appear instead. The single-authored approach is intimidating in scale and can result in loss of thoroughness or authority on individual topics. The alternatives lack scope or integration or both.

The idea for a book on anorthosites came to me in January of 1986 while returning to Houston after holiday festivities in Dallas. The original idea was a review paper on anorthosites, but by the time I reached Houston, the subject material I contemplated induding was obviously too extensive for a single paper. The Director of the Lunar and Planetary Institute, Kevin Burke, was receptive to the idea of a book, and suggested that I contact Peter Wyllie, who serves as Editor of the Springer-Verlag series Minerals and Rocks. This effort, which I originally expected would take about a year, has taken nearly 6. I have many excuses- indolence, moving to another continent, other commitments, etc.-but the basic truth is that writing a book is much larger an undertaking than can be anticipated. Many people are aware of this, and I was duly forewarned. . But why write a book on anorthosites? This is a very good question, which I have considered from many angles. One rationale can be expressed in terms of a comparison between anorthosite and basalt. A first-order understanding of basalt genesis has been extant for many years. By contrast, there is little agreement about the origin of anorthosite. There are good reasons for studying and writing about basalt: it is the most abundant rock type on the Earth's surface, and is also plentiful on the surfaces of the other terrestrial planets.

This series of monographs represents continuation on an inter­ national basis of the previous series MINERALOGIE UND PETRO­ GRAPHIE IN EINZELDARSTELLUNGEN, published by Springer­ Verlag. The voluminous results arising from recent progress in pure and applied research increase the need for authoritative reviews but the standard scientific journals are unable to provide the space for them. By their very nature, text-books are unable to consider specific topics in depth and recent research methods and results often receive only cursory treatment. Advanced reference volumes are usually too detailed except for experts in the field. It is often very expensive to purchase a symposium volume or an "Advances in . . . " for the sake of a specific review chapter surrounded by volume unrelated chapters. We hope that this monograph series will by­ pass these problems in fulfilling the need. The purpose of the series is to publish reviews and reports of carefully selected topics written by carefully selected authors, who are both good writers and experts in their scientific field. In general, the monographs will be concerned with the most recent research methods and results. The editors hope that the monographs will serve several functions, acting as supplements to existing text-books, guiding research workers, and providing the basis for advanced seminars. W. VON ENGELHARDT, Tiibingen July 1970 T. HAHN, Aachen R. RoY, University Park, Pa. J. W. WINCHESTER, Tallahassee, Fla. P. J. WYLLIE, Chicago, Ill. Preface Sub-series on "Isotopes in Geology".

This series of monographs represents continuation on an international basis of the previous series MINERALOGIE UNO PETROGRAPHIE IN EINZELOARSTELLUNGEN, published by Springer-Verlag. The voluminous results arising from recent progress in pure and applied re­ search increase the need for authoritative reviews but the standard scientific journals are unable to provide the space for them. By their very nature, text-books are unable to consider specific topics in depth and recent research met'hods and results often receive only cursory treat­ ment. Advanced reference volumes are usually too detailed except for experts in the field. It is often very expensive to purchase a symposium volume or an "Advances in . . . " volume for the sake of a specific review chapter surrounded by unrelated chapters. We hope that this monograph series will by-pass these problems in fulfilling the need. The purpose of the series is to publish, at reasonable prices, reviews and reports of care­ fully selected topics written by carefully selected authors, who are both good writers and experts in their scientific field. In general, the mono­ graphs will be concerned with the most recent research methods and results. The editors hope that the monographs will serve several functions, acting as supplements to existing text-books, guiding research workers, and providing the basis for advanced seminars. August 1967 W. VON ENGELHARDT, Tiibingen T. HAHN, Aachen R. Roy, University Park, Pa. J. W. WINCHESTER, Ann Arbor, Mich. P. J. WYLLIE, Chicago, Ill.

Zeolites form a family of minerals which have been known since the 18th century, but they remained a curiosity for scientists and collectors until 60 years ago, when their unique physicochemical properties attracted the attention of many researchers. In the past 30 years there has been an ex­ traordinary development in zeolite science; six International Conferences on Zeolites have been held every 3 years since 1967, and a large number of interesting contributions have been published in their proceedings. Many books, written either by individual authors or by several authors under a leading editor, have been published on these interesting silicate phases, but none has been devoted specifically to natural zeolites, even though this theme may be of interest not only to earth scientists, but also to chemists, as the in­ formation obtained from natural samples completes and in­ tegrates the characterization of many zeolites. We are trying to fill this gap on the basis of 20 years of research on natural zeolites, which we performed at the University of Modena together with many friends and colleagues. If it is in general difficult to write a scientific book with­ out upsetting somebody, this is particularly true for a book on natural crystals, because mineralogy is an interdisciplin­ ary science which covers some fields of physics, chemistry, it is almost impossible to meet every petrology, geology, and requirement.

Considerable progress has been made in our understanding of the physicochemical evolution of natural rocks through systematic analysis of the compositional properties and phase relations of their mineral assemblages. This book brings together concepts of classical thermodynamics, solution models, and atomic ordering and interactions that constitute a major basis of such analysis, with appropiate examples of application to subsolidus petrological problems. This book is written for an audience with a senior undergraduate level background in chemistry. Derivations of fundamental thermodynamic relations which are in need of reemphasis and clarification are presented.

This monograph was begun with two objectives in mind. The first was to provide a review of research involving the application of neodymium isotopic measurements to pro­ blems in earth science. In the process of organizing to do this, I realized that the research in this field had produced a need for an updated review of the underlying paradigms. This need had arisen because of the special properties of the samarium-neodymium isotopic system, and because the research had transgressed the traditional boundaries be­ tween the subfields of earth science. Without such a review, the significance of the results seemed likely to remain un­ necessarily obscure to interested scientists from related disciplines. Consequently, the second objective became the provision of a theoretical framework for the application of neodymium isotopic studies. Much of what this contains is not new, but it is drawn together here for the first time. At the time the writing was initiated, the literature of the field was still relatively limited. Over the past 5 years it has grown enormously. Considering the rate at which the writing progressed, it became clear that this could not be a fully up-to-date review and still reach completion. The selection of material for the review sections is biased toward earlier studies. Part I presents most of the background information.

There are several books emphasizing the mineralogical and petrological aspects of granites, but this book is the only one emphasizing the experimental aspects.

This series of monographs represents continuation on an inter­ nationai basis of the previous series MINERALOGIE UND PETRO­ GRAPHIE IN EINZELDARSTELLUNGEN, published by Sprin­ ger-Verlag. The voluminous results arising from recent progress in pure and applied research increase the need for authoritative reviews but the standard scientific journals are unable to provide the space for them. By their very nature, text-books are unable to consider specific topics in depth and recent research methods and results often receive only cursory treatment. Advanced reference volumes are usually too detailed except for experts in the field. It is often very expensive to purchase a symposium volume or an "Advances in . . " volume for the sake of a specific review chapter surrounded by unrelated chapters. We hope that this monograph series will by­ pass these problems in fulfilling the need. The purpose of the series is to publish reviews and reports of carefully selected topics written by carefully selected authors, who are both good writers and experts in their scientific field. In general, the monographs will be concerned with the most recent research methods and results. The editors hope that the monographs will serve several functions, acting as supple­ ments to existing text-books, guiding research workers, and providing the basis for advanced seminars. March 1971 W. VON ENGELHARDT, Tiibingen T. HAHN, Aachen R. Roy, University Park, Pa. J. W. WINCHESTER, Tallahassee, Fla. P. J. WYLLIE, Chicago, III. Contents 1 I. Introduction Sketch of Trollheimen 4 Acknowledgments . .

Professor OTTO BRAITSCH'S Entstehung und Stoffbestand der Salz- lagerstiitten has since its publication in 1962 enjoyed a reputation as the most complete and authoritative treatment, in any language, of the geochemistry of evaporites. The issue of this translation will now make it accessible to a much wider circle of readers. The years since first publica- tion of the German edition have seen a great surge of discussion and research on evaporites among English-speaking geologists, and while BRAITSCH'S work was important to some of these it can now no longer be ignored by any. It may be worth pointing out that, title notwithstanding, this volume takes as its subject not only the salts but all evaporite minerals and rocks, but that it makes no attempt to go beyond the geochemical evidence in discussing the origin of these evaporites. The reader should not expect to find here any extensive discussion of paleogeography and stratigraphy, or even petrographic detail. Within its scope of geochemistry and mineral- ogy the coverage is extensive.

Since the end of World War II isotope geology has grown into a diversi­ fied and complex discipline in the earth sciences. It has progressed by the efforts of a relatively small number of specialists, many of whom are physi­ cists, chemists, or mathematicians who were attracted to the earth sciences by the opportunity to measure and to interpret the isotopic compositions of certain chemical elements in geological materials. The phenomenal growth of isotope geology during the last 25 years is an impressive indi­ cation of the success of their efforts. We have now entered into a new phase of development of isotope geology which emphasizes the application of the new tools to the solution of specific problems in the earth and planetary sciences. This requires the active participation of a new breed of geologists who understand the nature and complexity of geological problems and can work toward their solution by a thoughtful application of the principles of isotope geology. It is there­ fore necessary to explain these principles to earth scientists at large to enable them to make use of the new information which isotope geology can offer them.

and their identification obviates individual thermochemical studies on every genus. The stability relations among sedimentary carbonate minerals are now more or less well known. The common rock-forming minerals cal­ cite and dolomite are indeed stable phases in the pertinent systems. Most other carbonate minerals of similar composition which are known to occur in the younger sediments are metastable with respect to calcite, dolomite, and magnesite. This implies that the sedimentation of carbon­ ates is determined only in part by stability relations. Kinetic factors, which allow the formation of metastable minerals, appear to be more important. Although the diagenetic transformations leading to stable minerals take place by virtue of thermodynamic requirements, the reac­ tions themselves are triggered by kinetic factors as well. Some of the reactions leading from metastable to stable carbonate assemblages are susceptible to simulation in the laboratory; others (e. g. dolomitization) appear to be so slow that they can be studied only in analogous systems characterized by reasonable reaction rates. In all attempts to explain the possible mechanisms of such reactions, we must consider the crystal structures of the final products as well as of the starting materials. This is another viewpoint from which mineralogy is important to carbonate petrology, if we regard the crystal chemistry of minerals as a part of mineralogy. A certain parallelism with clay mineralogy suggests itself.

This book represents the results of a lengthy study which Professor ALFRED RITTMANN began some thirty years ago. The relationship between the chemical and mineralogical composition of igneous rocks is established as far as is possible. Petrographers will appreciate that this problem is extremely complex, particularly since this relationship forms the basis of the classification and nomenclature of igneous rocks. The ingenious scheme of calculation of the CI.P.W. norm system is essentially chemical in nature. The compositions of the stoichiometrically ideal "normative minerals" do not correspond to those of the constituent minerals found in rocks. Although the "norm" is not intended to equal the "mode" or actual mineral composition of a rock, at least a qualitative agreement between the norm and the mode is desirable. For a number of rocks and rock groups, especially the leucocratic and silicic rocks, the deviation of the norm from the mode is generally within tolerable limits. For the melanocratic and highly subsilicic rocks, on the other hand, the CI.P. W. scheme of calculation too often yields results which fail to reflect the observed mineral composition. The anomalies produced in the cal­ culation of extremely subsilicic volcanic rocks have recently been briefly discussed by F. CHAVES and H. S. YODER, JR. (1971).

My goal in writing this book was to provide an introduction to meteorite science and a handbook on meteorite classification. Insofar as I succeeded it should prove useful both to the practicing professional and to university students at the upper-division and graduate levels. I originally intended the book to be nearly twice as long. The second half was to be a review of properties relating to the origin of each group of meteorites. Chapter XVIII is an example of how these later chapters would have looked, although most would not have been as interpretative. These chapters would have been useful chiefly to meteorite researchers looking for a quick summary of group properties; they were not written because of lack of time. Perhaps I will start to prepare this "second volume" in a year or so when my family and I have recovered from the preparation of the present volume. Although some parts of the classification portion are mildly icono­ clastic, I have attempted either to avoid the inclusion of speculative interpretations or to flag them with a caveat to the reader. I have relaxed these principles somewhat in Chapter XVIII to conserve space, but even there the discussion of alternative speculations should give the reader a feeling for the degree of uncertainty attached.

At first glance it may seem presumptuous to want to add yet another to the numerous books on Differential Thermal Analysis (DT A). Thermoanalytical methods have been in use for some time, as shown by the more than five thousand publications containing DT A or TG curves listed by SMOTHERS and CHIANG in the bibliography to their handbook and abstracted in the several volumes of Thermal Analysis Abstracts (TAA), edited by J. P. REDFERN for the International Con­ federation for Thermal Analysis (ICT A). Every three years the proceed­ ings of ICT A meetings are published, bringing the latest results of thermoanalytic research. There is also the Scifax DT A Data Index, edited by R. C. MACKENZIE (1962) and modeled on the ASTM pattern card index (used for X-ray investigations), a compilation of the DT A data for several hundred minerals, and inorganic and organic materials. The theoretical foundations of thermogravimetry and DT A have been described in detail by LEHMANN, DAS and PAETSCH (1953), R. C. MACKENZIE (1957, 1970), DUVAL (1963), WENDLANDT (1964), GARN (1965), F. PAULIK et al. (1966), SMOTHERS and CHIANG (1966), and KEATTCH (1969). Thermoanalytical results are strongly influenced by various factors relative to preparation and equipment (see 1-2. 4 of this study). This is the reason why we frequently find, in these books as well as in the Scifax-Card catalog, contradictory data on the same substance.

I was invited to write this book as part of the Minerals, Rocks and Organic Materials Series of Springer-Verlag by Professor Peter J. Wyllie in 1974. Ophiolites have preoccupied me ever since 1948 as a graduate student and up to the present time as part of my research with the U.S. Geological Survey. During this period ophiolite, an obscure European geological term, has attained an ever-increasing importance, is now used to include all fragments of ancient oceanic lithosphere incorporated into the orogenic zones of modern and ancient continental margins, and is a standard part of the plate tectonic paradigm. The purpose of this book is to provide a starting point for anyone interested in the background and state of knowledge concerning ophiolites (ancient oceanic lithosphere). Because ophiolites represent fragments of old oceanic crust their tectonic setting and age are extremely important in the reconstruction of ancient plate boundaries. Present­ day plate tectonic theories involve the generation and disposal of oceanic lithosphere, so that these ancient fragments of oceanic lithosphere can be used directly to reconstruct conditions within the ancient oceans. Since 1970, numerous meetings and conferences directly related to ophiolites have stimulated worldwide interest in the subject. As part of the International Correlation Program, the project "Ophiolites of Continents and Comparable Oceanic Rocks," was initiated by Dr. N. Bogdanov, Geological Institute, Moscow. This project has brought together an international group that has focused on the outstanding problems and is now producing a world map of ophiolite distribution.

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.

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.

Students of a phenomenon as common but complex as andesite genesis often are overwhelmed by, or overlook, the volume and diversity of relevant information. Thus there is need for periodic overview even in the absence of a dramatic breakthrough which "solves the andesite problem" and even though new ideas and data keep the issues in a state of flux. Thus I have summarized the subject through mid·1980 from my perspective to help clarify the long-standing problem and to identify profitable areas for future research. Overviews are more easily justified than achieved and there are fundamental differences of opinion concerning how to go about them. It is professionally dangerous and therefore uncom­ mon for single authors, especially those under 35 such as I, to summarize a broad, active field of science in book-length thor­ oughness. Review articles in journals, multi-authored books, or symposia proceedings appear instead. The single-authored approach is intimidating in scale and can result in loss of thoroughness or authority on individual topics. The alternatives lack scope or integration or both.

The idea for a book on anorthosites came to me in January of 1986 while returning to Houston after holiday festivities in Dallas. The original idea was a review paper on anorthosites, but by the time I reached Houston, the subject material I contemplated induding was obviously too extensive for a single paper. The Director of the Lunar and Planetary Institute, Kevin Burke, was receptive to the idea of a book, and suggested that I contact Peter Wyllie, who serves as Editor of the Springer-Verlag series Minerals and Rocks. This effort, which I originally expected would take about a year, has taken nearly 6. I have many excuses- indolence, moving to another continent, other commitments, etc.-but the basic truth is that writing a book is much larger an undertaking than can be anticipated. Many people are aware of this, and I was duly forewarned. . But why write a book on anorthosites? This is a very good question, which I have considered from many angles. One rationale can be expressed in terms of a comparison between anorthosite and basalt. A first-order understanding of basalt genesis has been extant for many years. By contrast, there is little agreement about the origin of anorthosite. There are good reasons for studying and writing about basalt: it is the most abundant rock type on the Earth's surface, and is also plentiful on the surfaces of the other terrestrial planets.

This series of monographs represents continuation on an inter­ national basis of the previous series MINERALOGIE UND PETRO­ GRAPHIE IN EINZELDARSTELLUNGEN, published by Springer­ Verlag. The voluminous results arising from recent progress in pure and applied research increase the need for authoritative reviews but the standard scientific journals are unable to provide the space for them. By their very nature, text-books are unable to consider specific topics in depth and recent research methods and results often receive only cursory treatment. Advanced reference volumes are usually too detailed except for experts in the field. It is often very expensive to purchase a symposium volume or an "Advances in . . . " for the sake of a specific review chapter surrounded by volume unrelated chapters. We hope that this monograph series will by­ pass these problems in fulfilling the need. The purpose of the series is to publish reviews and reports of carefully selected topics written by carefully selected authors, who are both good writers and experts in their scientific field. In general, the monographs will be concerned with the most recent research methods and results. The editors hope that the monographs will serve several functions, acting as supplements to existing text-books, guiding research workers, and providing the basis for advanced seminars. W. VON ENGELHARDT, Tiibingen July 1970 T. HAHN, Aachen R. RoY, University Park, Pa. J. W. WINCHESTER, Tallahassee, Fla. P. J. WYLLIE, Chicago, Ill. Preface Sub-series on "Isotopes in Geology".