Selection of papers from the IGCP Project 157 and 160 meeting at the Univ. Nacional Autonoma de Mexico, 11-14 Jan. 1982

Since 1964, the time when the Upper Mantle Project was started, the Precambrian continental crust has been studied in considerable detail in many areas. Multidisciplinary studies, using modern tools and techniques have resulted in increasing levels of accuracy. The Precambrian continental crust has been subjected to several thermal events and multiple episodes of deformation. These events have obliterated the scenario produced by early events and present-day efforts are directed towards evaluating the cause-effect processes of each event. How far back the known geological processes of the Phanerozoic can be extended into the Precambrian is one of the main questions. The present volume provides data and interpretations which will help in formulating the answer to some of these questions.The book contains 30 contributions resulting from researches on almost all the important Precambrian terranes.

The book deals with the record of important Neoproterozoic to Early Palaeozoic events in southwestern Gondwana, that heralded the Cambrian explosion and the dawn of modern ecosystems. It contains a detailed account of the Neoproterozoic to Cambrian geological record in a poorly-known part of the world, which is at the same time key to understand fundamental processes at the Proterozoic-Cambrian transition. The emphasis is placed on litho-, bio-, chemostratigraphy and magmatism. The palaeoclimatic, tectonic, evolutionary radiation and extinction events and associated mineralizations will be identified and discussed. A synthesis of all data is provided at the end of the book, integrating the data from all cratons and fold belts in southwestern Gondwana. The events will be individualized, their impact discussed and correlations between different successions both within and outside Gondwana proposed.The book is organized in three sections. Section one is an introduction to the neoproterozoic and Cambrian seen as a time of upheavals, extremes and innovations. Section two comprises nineteen chapters dealing with the neoproterozoic-Cambrian events in southwestern Gondwana. Section three will provide a synthesis on every major topic, and a critical assessment of the global implications of the presented data. - The book deals with the record of important Neoproterozoic to Early Palaeozoic events in southwestern Gondwana, that heralded the Cambrian explosion and the dawn of modern ecosystems - It contains a detailed account of the Neoproterozoic to Cambrian geological record in a poorly-known part of the world, which is at the same time key to understand fundamental processes at the Proterozoic-Cambrian transition - The emphasis is placed on litho-, bio-, chemostratigraphy and magmatism

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.