Greenstone Gold and Crustal Evolution


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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 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.







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.




Classic Cordilleran Concepts


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Open-file Report


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Geology of the Precambrian Superior and Grenville Provinces and Precambian Fossils in North America


Book Description

This volume contains a description of the geology and mineral deposits of the Superior Province of the Canadian Shield, an overview of Grenville Province geology, and a synopsis of Precambrian fossil occurrences in North America. Six large plates include a geological map of Canada, geological map of the Grenville Province, lithotectonic map of the Superior Province, Archean mineral deposit map of the Superior Province, and more.




Archean-Mesoproterozoic Crustal Evolution and Crust-Mantle Geodynamics of Western Liaoning-Northeastern Hebei Provinces, North China Craton


Book Description

This thesis presents geological, petrological, geochemical, and zircon U–Pb–Lu–Hf isotopic field data for representative Precambrian lithologies in the Western Liaoning-Northeastern Hebei Provinces along the northern margin of the North China Craton (NCC). It describes late Neoarchean (2.64–2.48 Ga) supracrustal metavolcanic rocks and granitoid gneisses; late Paleoproterozoic (1.72–1.68 Ga) Jianping alkaline plutons and Pinggu alkaline volcanic rocks; and newly discovered ~1.23 Ga mafic dykes. The nature of magma sources and genesis of each magmatic episode are investigated, and the Precambrian (~2.6–1.2 Ga) lithospheric mantle evolution and crust-mantle interaction processes are established for the first time –aspects that provide important constraints in our understanding of the Precambrian crustal evolution and geodynamic processes in the region studied.




African Mining ’91


Book Description

The second 'African Mining' conference is planned for June 1991, and follows the first, very successful, event held in May 1987. That full four-year period was characterized by substantial changes in the political and economic climate of many countries in both hemispheres. Copper prices were relatively firm, and the advance and steady demand for nickel and ferrochromium stabilized important sectors of the mineral industry, certainly in Zimbabwe. The promise for gold remained unfulfilled, but the smaller, relatively flexible, mines survived and only the large, deep and low-value mines seem seriously at risk. None of this has affected the hungry, and intensive exploitations from surface to the water-table have revealed many targets of promise to those willing to take the risks. The pattern in Southern Africa was extraordinarily stable among the turmoil, with independence for Namibia, adjustments in South Africa and a gradual shift to market economies in the region. The pace of exploration has increased to recover some part of the progress that was lost in the Independence struggle, and atthe end of the first decade in Zimbabwe, for example, oil is being sought in the Zambesi Rift, following the investigation of the Luangwa in Zambia, and there are exciting exploration projects for methane released from coal, deep in its basins.