Proterozoic Crustal Evolution

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.

The main goal of this book is to provide a modern comprehensive statement on the Earth's Precambrian crust. It uses geographic and tectonic location, lithostratigraphy, geochronology, and petrogenesis as a basis for considering Precambrian coastal evolution--including the role of plate tectonics. Detailed consideration is given to the endogenic and exogenic processes which formed the continental crust and also to its subsequent secular evolution across Precambrian time**An essential reference volume for every Precambrian geologist.

This volume provides a synthesis of Archaean and Proterozoic crustal evolution in the North Atlantic Region. There is particular reference to Proterozoic collisional tectonics. The main topics include: Archaean crustal growth; Proterozoic crustal growth; orogenic processes during the Proterozic; geochronology of Proterozoic tectono-thermal processes; and provenance of Proterozoic sediments.

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.

Precambrian Crustal Evolution of China integrates the theory of plate tectonics, structural geology and petrology to identify the tectonic and metamorphic environment in different stages of development of the Archaean and Proterozoic crust. Further, the evolution of the Precambrian atmosphere and hydrosphere is approached by using geochemical data and traces of life. For the first time, the results of the study of the Precambrian geology of China are made available in English to scientists and students not having access to the huge amount of Chinese literature.

This comprehensive text presents a thorough coverage of the key area of plate tectonics and crustal evolution which is suitable for advanced undergraduate and masters courses. This fourth edition bring the text fully up-to-date, with coverage of the latest research in crustal evolution, supercontinents and mass extinctions. A new chapter covers the feedbacks of various Earth systems. In addition, a new appendix provides a valuable survey of current methodology.