Deformation Of The Continental Crust

This volume presents a selection of papers showing the current focus of studies of deformation structures and processes within the continental crust. The selected contributions use a large range of analytical techniques suited to the full range of structure sizes and fine-tuned to the physical process that controls the deformation, from the grain boundary at the micro-scale, the lithological contact at the meso-scale to the plate boundary at the global scale. The papers in the volume are grouped into three sections relating to specific lines of research within the analysis of rock deformation structures and processes, in particular in respect to the continental crust: structures within shear zones and faults; magmatic structures, and microstructures and rheology. These sections include papers describing field studies, experimental rock deformation and numerical modelling of deformation processes.

Traditionally, investigations of the rheology and deformation of the lithosphere (the rigid or mechanically strong outer layer of the Earth, which contains the crust and the uppermost part of the mantle) have taken place at one scale in the laboratory and at an entirely different scale in the field. Laboratory experiments are generally restricted to centimeter-sized samples and day- or year-length times, while geological processes occur over tens to hundreds of kilometers and millions of years. The application of laboratory results to geological systems necessitates extensive extrapolation in both temporal and spatial scales, as well as a detailed understanding of the dominant physical mechanisms. The development of an understanding of large-scale processes requires an integrated approach. This book explores the current cutting-edge interdisciplinary research in lithospheric rheology and provides a broad summary of the rheology and deformation of the continental lithosphere in both extensional and compressional settings. Individual chapters explore contemporary research resulting from laboratory, observational, and theoretical experiments.

Summary of recent research covering experimental methods and numerical modelling, for graduate students and researchers.

Traditionally, investigations of the rheology and deformation of the lithosphere (the rigid or mechanically strong outer layer of the Earth, which contains the crust and the uppermost part of the mantle) have taken place at one scale in the laboratory and at an entirely different scale in the field. Laboratory experiments are generally restricted to centimeter-sized samples and day- or year-length times, while geological processes occur over tens to hundreds of kilometers and millions of years. The application of laboratory results to geological systems necessitates extensive extrapolation in both temporal and spatial scales, as well as a detailed understanding of the dominant physical mechanisms. The development of an understanding of large-scale processes requires an integrated approach. This book explores the current cutting-edge interdisciplinary research in lithospheric rheology and provides a broad summary of the rheology and deformation of the continental lithosphere in both extensional and compressional settings. Individual chapters explore contemporary research resulting from laboratory, observational, and theoretical experiments.

One of the most interesting results obtained in the last two decades in the study of crustal deformation has been the recognition that large regions of continental crust undergo rotations about vertical axis during deformation. Proof of such rotations has come through the paleomagnetic studies, which reveal rotations when paleomagnetic declinations within the deforming region arc compared with those found in coeval rocks in the stable regions outside the deforming zone. Such rotations were first described in Oregon then in the North American Cordilleras and in Southern California and were a surprise to everyone. Even in California which, as a result of oil exploration, was among the best geologically explored regions in the world, no one could claim to have predicted that these rotations would be found. Rotations have subsequently been found in other areas of recent continental tectonic activity, notably in the Basin and Range province, New Zealand, the Andes, Greece and Western Turkey, so that they appear as an important feature of continental deformation.

"This book contains landmark papers on the processes of formation of continental crust from its beginnings in the Archean to modern processes, as well as discussions of several ancient and modern orogenic belts. The book is international in scope, with contributions from geoscientists dealing with crustal processes on five continents, and articles from more than 50 non-U.S. authors and co-authors."--Publisher's website.