Proterozoic Crustal Evolution


Book Description

As a final product of the International Geological Correlation Program (IGCP) Project 217, this volume brings together significant advances in the understanding of Proterozoic crustal evolution. This IGCP Project focussed on nine research objectives: 1) Comparison of Archean and Proterozoic supracrustal assemblages to more fully understand differences between Archean and post-Archean tectonic regimes; 2) To more fully understand the geochemical differences between Archean and post-Archean sediments and to evaluate the various factors that control sediment composition; 3) From combined U/Pb zircon and whole-rock Sm/Nd studies, to see if the apparent 2.4-2.0 continental crust "generation gap" is real; 4) To employ new techniques in the dating of individual zircons to more fully understand Proterozoic tectonic history and the role of crustal reworking; 5) From trace element ratios and Nd isotopic data from basalts, to better understand Proterozoic mantle evolution; 6) To encourage more detailed studies of the anorogenic granite-anorthosite association to better understand its origin and significance in terms of crustal evolution; 7) From combined Nd, Pb, and Sr isotopic data, to more precisely estimate the amount of new continental crust formed during the Proterozoic; 8) To encourage joint P-T and geochronological studies of Proterozoic and high-grade terranes to better understand Proterozoic orogenesis: and 9) To try and understand why hydrothermal precious metal deposits are relatively rare in the Proterozoic compared to both the Archean and the Phanerozoic. The book should be of interest to professionals in the geosciences (especially geochemists, petrologists and structural geologists) and graduate students in the same fields.




Archean Crustal Evolution


Book Description

The integration of Tectonics/Geochemistry, up-to-date reviews by leading scientists as well as a broad topical coverage of the Archean, are some of the features of this particular volume. As geochronology has progressed in the last 20 years, the Archean has continued to attract interest. Advancements in the understanding of Archean crustal and mantle evolution have progressed rapidly since the first International Archean Symposium in Western Australia (1970). The landmark for the Archean was the NATO Advanced Study Institute at Leicester (1975). At this meeting the Archean truly "came of age". Investigators from many different disciplines focused their expertise on the early history of the earth. For the first time, the nature of the atmosphere, oceans, and life during the Archean was an important part of an Archean symposium. During the most recent Archean Symposium in Perth in 1990, there was a shift in interest from field and trace element data to the new rapidly evolving high-precision U/Pb geochronology of Archean rocks and to detailed structural studies of both low and high grade Archean terrains. The terrane concept so widely applied to the Phanerozoic was proposed for the Archean Yilgarn Province in Western Australia and is now widely accepted for the Archean (as evident by the articles in this book). Plate tectonics is now widely accepted as the principal process that controls the history of continents and oceans. There are, though, well substantiated differences between Archean and post-Archean rocks that indicate that Archean tectonic regimes must have differed in some respects from modern ones. The question of how and to what degree did Archean plate tectonics differ from modern plate tectonics is treated in many of the chapters of this book. Altogether, the editor has presented a selection of articles that provide a fascinating insight into the latest observations in this field.




Crustal Evolution of Southern Africa


Book Description

Syntheses of the geology of major areas of the Earth's crust are increasingly needed in order that the features of, and the problems associated with, the secular evolution of the continents can be understood by a wide audience. Southern Africa is fortunate in having a remarkable variety of geological environments developed without many breaks over 3. 8 Ga, and many of the rock groups are household names throughout the geological world. In one respect the geology of Southern Africa is particularly important: cratonization clearly began as early as 3. 0 Ga ago, in contrast to about 2. 5 Ga in most other continental areas such as North America. This book documents very well the remarkable change in tectonic conditions that took place between the Early and Mid-Precambrian; we have here evidence of the very earliest development of rigid lithospheric plates. This book is a tribute to the multitudes of scientists who have worked out the geology of Southern Africa over many years and decades. Whatever their discipline, each provided a step in the construction of this fascinating story of 3. 8 Ga of crustal development. In the book the reader will find a detailed review of the factual data, together with a balanced account of interpretative models without the indulgence of undue speculation. One of its attractions is its multidisciplinary approach which provides a stimulating challenge to the reader.




Proterozoic East Gondwana


Book Description

This volume focuses on Late Mesoproterozoic to early Cambrian events related to Gondwana assembly and break up. The nineteen papers provide a comprehensive review including advanced knowledge and new data from all critical areas of East Gondwana. The recent knowledge of the evolution of East Gondwana, which was regarded as an integral part of the Mesoproterozoic supercontinent Rodinia, is the major theme of the volume, which is reinforced by highlighting this radical and new understanding of the evolution of this region.




Principles of Precambrian Geology


Book Description

Principles of Precambrian Geologyis an update to the 1991 book, Precambrian Geology: The Dynamic Evolution of the Continental Crust, by the same author. The new edition covers the same topics in a more concise and accessible format and is replete with explanatory figures, tables, and illustrations. The book serves as a modern comprehensive statement on the Earth's Precambrian crust, covering the main aspects of distribution, lithiostratigraphy, age, and petrogenesis of Precambrian rocks by continent within the context of the Earth's evolving continental crust. Principles of Precambrian Geology provides a suitable framework for assessing various Earth dynamic and biospheric hypotheses, including the modern plate tectonic paradigm and the Gaian hypothesis. Despite the concise format, the new edition provides extensive updated references to support the information presented. It is designed to serve the needs of student, teacher, explorationist and general student of the continental crust. - Updated to provide more concise accessible information - Extensive illustrations, tabulations, and maps - Provides a framework for assessing recent hypothesis on Earth dynamics - Covers main aspects of distribution, lithostratigraphy, age, and protogenesis of Precambrian rocks







Plate Tectonics & Crustal Evolution


Book Description

This substantially revised edition includes recently published information relating to plate tectonics and continental origin. A large number of new figures have been added, and new sections included on meteorites, seismic tomography, mantle convection, accretionary terranes, mantle sources and evolution, continental growth, secular changes in Earth history, also a new chapter on exogenic Earth systems. In addition the following topics have been substantially revised: lunar origin, global gravity, origin of the core, metamorphism, plate boundaries, hotspots, tectonic settings, and magma associations. Among the new features the Tectonic Map of the World has also been updated.




Crustal Evolution and Metallogeny in India


Book Description

Crustal evolution means the resultant changes that the Earth's crust has gone through in its geologic past affected by changes in the mantle-crust system, the atmosphere, the hydrosphere and the biosphere. Metallogeny is the genesis of metallic mineral deposits. Both the terms are used in the book in their conventional sense, but keeping in mind an Indian context. This book is the first of its kind to document in detail the nature, origin and evolution of mineral deposits in India and is contextualized in local, regional and global geology. The book is unique in that it combines both metallogeny and crustal evolution that were hitherto treated as stand-alone topics. The exhaustive chapters in the book carry detailed case studies of the distribution and occurrence of ores. The book would be useful to students of advanced geology, researchers, teachers, planners and global metallogeneticists around the world.




Geology of North America—An Overview


Book Description

Summaries of the major features of the geology of North America and the adjacent oceanic regions are presented in 20 chapters. Topics covered include concise reviews of current thinking about Precambrian basement, Phanerozoic orogens, cratonic basins, passive-margin geology of the Atlantic and Gulf Coast regions, marine and terrestrial geology of the Caribbean region and economic geology.