Granulites And Crustal Evolution

Proceedings of the NATO Advanced Research Workshop on Petrology and Geochemistry of Granulites, Clermont-Ferrand, France, September 5-9, 1988

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.

This Book Is In Commemoration Of The Life And Work Of Professor R.S. Sharma, An Eminent Metamorphic Petrologist And Mineralogist. It Incorporates The Latest Developments In The Field Of Metamorphic Petrology. The Volume Is Divided Into Five Sections, Namely Metamorphism, Fluid Processes, Himalayan Metamorphism, Uhp/ Uht Metamorphism, And Geochronology & Geochemistry. The Book Would Be Of Great Interest To All Geoscientists Concerned With Metamorphic Processes And Crustal Evolution.The Main Topics Covered In The Book Include:The Granulite Facies, Crustal Melting, And Prograde And Retrograde Phase Equilibria In Metapelites At The Amphibolite To Granulite Facies Transition Tim E. Johnson And M. Brown; Evolution Of Early Proterozoic Metamorphism Within Tim-Yastrebovskaya Paleorift, Voronezh Crystalline Massif, East-European Platform: Metapelite Systematics, Phase Equilibrium, And P-T Conditions Tatyana N. Polyakova, Konstantin A. Savko, Vyacheslav Yu. Skryabin; Metamorphosed Carbonate-Evaporitic Rocks At Transition Of High-Pressure Amphibolite/Eclogite Facies Conditions: A Case Study From The Sare Sang Lapis-Lazuli Deposit (Afghanistan) Shah Wali Faryad; Petrogenesis And Evolution Of Peña Negra, An Anatectic Complex In The Spanish Central System M. Dolores Pereira Gómez; Polymetamorphism In The Archaean Gneiss Complex Of Shivpura Gyangarh, District Bhilwara, Rajasthan H. Thomas; Ibc Granulite In Clockwise Pressure-Temperature Regime: A Case From The Orissa Sector Of Eastern Ghats Mobile Belt S.C. Patel; Carbonates In Feldspathic Gneisses From The Granulite Facies: Implications For The Formation Of Co2-Rich Fluid Inclusions William Lamb; Growth And Exhumation Of The Lower Crust Of The Kohistan Arc, Nw Himalayas T. Yoshino And T. Okudaira; Evidence Of Upper Amphibolite Facies Metamorphism From Almora Nappe, Kumaun Himalayas Mallickarjun Joshi And A.N. Tiwari; Is Muscovite In The Mandi Granite Primary? A Guide To Distinction Between The Lower Paleozoic And Tertiary Granites Of The Himalayas S. Nag, S. Sengupta And P.K. Verma; Modeling Of P-T-T Paths Constrained By Mineral Chemistry And Monazite Dating Of Metapelites In Relationship To Mct Activity In Sikkim, Eastern Himalayas Chandra S. Dubey, E.J. Catlos And B.K. Sharma; Uhp Metamorphism And Continental Subduction/Collision J.G. Liou, T. Tsujimori, I. Katayama And S. Maruyama; Uht Metamorphism And Continental Orogenic Belts A. Mohan, I.N. Sharma And P.K. Singh; Single Zircon Dating Of Hypersthene-Bearing Granitoid From Balaram-Abu Road Area, Southern Part Of The Aravalli Mountains, Nw India: Implications For Malani Magmatism Related Thermal Event A.B. Roy, Alfred Kröner, Vivek Laul And Ritesh Purohit; Geochemistry And Petrogenesis Of The High Grade Granulites From Kodaikanal, South India D. Prakash And H. Thomas; The Lower Crust Of The Indian Shield: Its Characteristics And Evolution T.M. Mahadevan

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.

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.

This book reviews current ideas explaining the formation of granite in terms of melting, segregation, ascent and emplacement. It introduces an alternative hypothesis that granites are endogenic in that they essentially form and remain at melting sites in the middle–upper crust under conditions of abnormally high heat flow. The book highlights results of Chinese research over the last 30 years in English for the first time.

The Proterozoic aeon involved at least three major continental readjustments. India and Antarctica appear in most models of supercontinent reconstructions, but their relative position has been the subject of debate. High-resolution petrological and geochronological data, especially from the Proterozoic mobile belts, provide the principal means of resolving this issue. The ice-covered nature of Antarctica allows only limited access to the rocks, and then only in coastal tracts, so detailed studies in more accessible Proterozoic terrains in India assume added significance. This volume, a follow-up to the XII International Symposium on Antarctic Earth Science, Goa (a SCAR symposium), provides new data from selected locations in east Antarctica (Enderby Land and Dronning Maud Land) and from India, including the Eastern Ghats Mobile Belt (EGMB), Chota Nagpur Gneissic Complex, the Khasi Hills and the Aravalli–Delhi Mobile Belt. The presented geochronological data, constrained by petrological studies, are expected to provide new insights, especially into the EGMB–east Antarctica connection and the rate of continental readjustments in the post-Rodinia break-up.