Magnetic Fabric Constraints On The Emplacement Of Igneous Intrusions

This edited work contains the most recent advances related to the study of layered intrusions and cumulate rocks formation. The first part of this book presents reviews and new views of processes producing the textural, mineralogical and geochemical characteristics of layered igneous rocks. The second part summarizes progress in the study of selected layered intrusions and their ore deposits from different parts of the world including Canada, Southwest China, Greenland and South Africa. Thirty experts have contributed to this update on recent research on Layered Intrusions. This highly informative book will provide insight for researchers with an interest in geology, igneous petrology, geochemistry and mineral resources.

This volume provides a synopsis of current research on volcanic processes, as gained through the use of palaeomagnetic and rock magnetic techniques. Thermoremanent magnetization information provides a powerful means of deciphering thermal processes in volcanic deposits, including estimating the emplacement temperature of pyroclastic deposits, which allows us to understand better the rates of cooling during eruption and transport. Anisotropy of magnetic susceptibility and anisotropy of remanence are used primarily to investigate rock fabrics and to quantify flow dynamics in dykes, lava flows, and pyroclastic deposits, as well as identify vent locations. Rock-magnetic characteristics allow correlation of volcanic deposits, but also provide means to date volcanic deposits and to understand better their cooling history. Because lava flows are typically good recorders of past magnetic fields, data from them allow understanding of changes in geomagnetic field directions and intensity, providing clues on the origin of Earth’s magnetic field.

Encyclopedia of Geology, Second Edition presents in six volumes state-of-the-art reviews on the various aspects of geologic research, all of which have moved on considerably since the writing of the first edition. New areas of discussion include extinctions, origins of life, plate tectonics and its influence on faunal provinces, new types of mineral and hydrocarbon deposits, new methods of dating rocks, and geological processes. Users will find this to be a fundamental resource for teachers and students of geology, as well as researchers and non-geology professionals seeking up-to-date reviews of geologic research. Provides a comprehensive and accessible one-stop shop for information on the subject of geology, explaining methodologies and technical jargon used in the field Highlights connections between geology and other physical and biological sciences, tackling research problems that span multiple fields Fills a critical gap of information in a field that has seen significant progress in past years Presents an ideal reference for a wide range of scientists in earth and environmental areas of study

viii debate of those earlier days has been beautifully summarized by H. H. Read in his famous "Granite Controversy" (1957). Read's formulation of the controversy occurred at the time when geochemistry was as a new and powerful tool. The new techniques opened era during which emerging an granites were considered mainly from this new viewpoint. Geochemical signatures have shown that mantle and crustal origins for granites were both possible, but the debate on how and why granites are emplaced did not progress much. Meanwhile, structural geology was essentially geometrical and mechanistic. In the early 70's, the structural approach began to widen to include solid state physics and fluid dynamics. Detailed structural maps of granitic bodies were again published, mainly in France, and analysed in terms of magmatic and plastic flow. The senior editor of this volume and his students deserve much of the credit for this new development. Via microstructural and petrofabric studies, they were able to discriminate between strain in the presence of residual melt or in the solid-state, and, by systematically measuring magnetic fabrics (AMS), they have been able to map magmatic foliations and lineations in ever finer detail, using the internal markers within granites coming from different tectonic environments. The traditional debate has been shifted anew. The burning question now seems to be how the necessary, large-scale or local, crustal extension required for granite emplacement can be obtained.

The relationship between magnetic fabric and petrofabric is complex and depends on various factors including the composition, concentration and grain size of mineral grains. Ongoing research in geological applications is paralleled by studies of the fundamental mineral magnetic phenomena involved. The papers in this book represent the current state of investigations in magnetic anisotropy studies as a discipline that integrates geological interpretations, mineral fabric development, technical advances and rock-magnetic properties.

This book offers a high-level summary of shallow magmatic systems (dykes, sills and laccoliths) to support geoscience master and PhD students, scientists and practicing professionals. The product of the LASI (Laccoliths and Sills conference) workshop, it comprises thematic sections written by one or more experts on the respective field. It features reviews concerning the physical properties of magma, geotectonic settings, and the structure of subvolcanic systems, as well as case studies on the best-known systems. The book provides readers a broad and comprehensive understanding of the subvolcanic perspective on pluton growth, which is relevant for mineralogical processes as well as the genesis of mineral deposits.