Search results for: lamprophyres

Lamprophyres

Author : N. M. S. Rock
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Following their recognition by GUmbel (1874), lamprophyres were treated for an entire century as little more than obscure curiosities. Although this situation has changed recently, with a flowering of publications and active workers, lamprophyres remain almost the only group of igneous rocks which have not yet received attention in a dedicated monograph. In five exploratory reviews (1977-1987), the writer aimed to set out what was known about these rocks. The lUGS Subcommission on igneous rock systematics had meanwhile presented its nomenclatural framework (Streckeisen 1979). All this has now been overtaken by a recent explosion of interest, epitomized not least by lamprophyres' greater prominence in the 4th International Kimberlite Conference Proceedings. More data have become available since 1985 than over the entire previous century, and it is obviously impossible for such an extraordinary outpouring to be fully reviewed in this first, preliminary book. At the risk of dissatisfying some readers, therefore, this book concentrates on factual matters, and on a broad overview rather than minutiae. Because not even a world map of known lamprophyres was previously available, almost half the book is deliberately taken up by the first global lamprophyre compilation, and its commensurately extensive Bibliography. Such a compendium of largely objective information is believed to be of more immediate interest and lasting value than a premature pottage of petrogenetic polemic. Chapters 1-7 bring previous studies up to date, and concentrate on factual information.

Metallogeny and Petrogenesis of Lamprophyres in the Mid European Variscides

Author : Thomas Seifert
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Presents a model important for the exploration for Sn, W, Mo, Ag, Cu, Zn, Pb, In, and U mineralization in the Bohemian Massif and comparable ore deposit provinces worldwide.

Lamprophyres Lamproites and Related Rocks

Author : L. Krmíček
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Paleoproterozoic to Cenozoic lamprophyres, lamproites and related rock types (e.g., orangeites, kimberlites) are volatile-rich mafic magmatic rocks with a unique potential for the investigation of processes affecting mantle reservoirs. They originated from primary mantle-derived melts that intruded both cratons and off-craton regions, which were parts of former supercontinents – Columbia, Rodinia and Gondwana–Pangea. Well-known for hosting economic minerals and elements such as diamonds, base metals, gold and platinum-group elements, they are also significant for our understanding of deep-mantle processes, such as mantle metasomatism and mantle plume–lithosphere interactions, as well as large-scale geodynamic processes, such as subduction-related tectonics, and supercontinent amalgamation and break-up. This book aims to provide a timely overview of the state-of-the-art and recent advances as achieved by various research groups around the world. Mineralogical, geochemical, geochronological and isotope analyses are used to decipher the complex petrogenesis and metallogenesis of these extraordinary rocks, and unravel a complete history of tectonic events related to individual supercontinent cycles.

Mineral Deposits at the Beginning of the 21st Century

Author : A. Piestrzynski
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The Joint 6th Biennial SGA-SEG Meeting was held in Krakow in August 2001. This volume contains 274 extended abstracts, grouped thematically under 18 session titles covering topics such as lead-zinc deposits; metamorphism affecting mineral deposits; and the environmental aspects of mining.

Igneous Petrogenesis A Global Tectonic Approach

Author : B.M. Wilson
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As a major text in igneous petrology, this innovative book offers a much-needed, radically different approach to the study of igneous rocks. Bridging a long-recognized gap in the literature by providing petrogenic models for magmatismin terms of global tectonic processes, it encompasses geophysics and geochemistry in a comprehensive treatment of the subject. Most textbooks in igneous petrology have intended to avoid discussion of potentially controversial petrogenetic models. However, this is precisely the sort of information senior students of igneous petrology require. Dr Wilson has drawn on 15 years of research and 10 years of teaching experience in writing an account of what is now a well established understanding of the processes involved in environments of magma generation. She provides full discussions of the major-element, trace-element, and radiogenic isotope characteristics of magmas generated in different tectonic settings and she deals with the information derived from such data concerning magma source regions and their ascent trough the Earth's lithosphere. Additionally each chapter contains a summary of geophysical data relating to crustal and mantle structure and the location of magma reservoirs. The modular format of the book will facilitate its use by all students, researchers and professionals with an interest in igneous petrology. A basic knowledge of geochemistry, mineralogy, phase diagrams, regional geology and global tectonics is assumed, but such advanced topics as trace element and isotope geochemistry can be omitted initially if the reader's background is inappropriate. The text is profusely illustrated and the bibliography contains over 1000 carefully selected references. Marge Wilson graduated in geology at the University of Oxford. She then spent a year at the University of California, Berkeley, and subsequently studied the petrogenesis of nepheline syenites from the Gardar province of Greenland, leading to a PhD from the University of Leeds. Her research has focused on island-arc, oceanic-island and intra-continental plate tectonic settings.

Igneous Rocks

Author : Alok K Gupta
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Petrology of Lamproites

Author : Roger H. Mitchell
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In this book, the first dedicated entirely to the petrology of lamproites and their relationships to other potassium-rich rocks, the objective of the authors is to provide a comprehensive critical review of the occurrence, mineralogy, geochemistry, and petrogenesis of the clan. Although lamproites represent one of the rarest of all rock types, they are both economically and scientifically important and we believe the time is ripe for a review of the advances made in their petrology over the past two decades. Many of these advances stem from the recognition of diamond-bearing lamproites in Western Australia and the reclassification of several anomalous diamond-bearing kim berlites as lamproites. Consequently lamproites, previously of interest only to a small number of mineralogists specializing in exotica outside the mainstream of igneous petrol ogy, have become prime targets for diamond exploration on a worldwide basis. Contemporaneously with these developments, petrologists realized that lamproites possess isotopic signatures complementary to those of midoceanic ridge basalts, alkali basalts, kimberlites, and other mantle-derived melts. These isotopic studies provided new insights into the long-term development of the mantle by suggesting that the source regions of lamproites were metasomatically enriched in light rare earth and other incompatible elements up to 1-2 Ga prior to the melting events leading to generation of the magma.

The Metallogeny of Lode Gold Deposits

Author : Ulrich Kretschmar
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The Metallogeny of Lode Gold Deposits: A Syngenetic Perspective is a synthesis of lode gold vein forming processes, addressing the commonality in similar worldwide deposits. The book’s empirical model incorporates widely known and accepted principles of ore deposition and shows how it applies in the volcanic-sedimentary greenstone belt environment. Several chapters detail outcrop maps and photos of field occurrences and textures. The interpretations flow directly from the authors’ field work, and are coupled with analyses of underlying physical processes. Utilizing detailed geological mapping, field work, and chemical analyses as the basis of a syngenetic formation mode, the text arms readers with the tools necessary to accurately analyze and interpret new data on the subject. This includes information on decoding the significance of asymmetry in vein formation, as well as the role of lamprophyres in gold camps, how Archean geology requires integration into a lode vein formation model, and how to develop an understanding of the worldwide applicability of gold cycles to lode vein formation and exploration and how it can be applied to deposits of all ages. Presents the first book to galvanize lode gold research into a single authoritative reference Simplifies the complexity of lode gold’s underlying processes and presents valid concepts surrounding the lode gold forming environment Features color figures, illustrations, and photos that enrich the content’s focus and aid in the retention of key concepts

Geological Survey of Canada Open File 3228

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Neogene Quaternary Continental Margin Volcanism

Author : Claus Siebe
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