Atlas of Deformed and Metamorphosed Rocks from Proterozoic Orogens

Atlas of Deformed and Metamorphosed Rocks from Proterozoic Orogens is a richly illustrated reference book featuring 400 full-color images of varied rock compositions, each with a concise description providing location, lithology, structural fabric, possible deformational history, metamorphic features, and other important geological information. Its relevance and significance in understanding the geological and tectonic history of the region is highlighted by providing relevant key references. The high-grade rocks included in the Atlas are mostly from the regions of Proterozoic orogenic belts. However, some of the regions in these orogenic belts are often covered by sediments, glacial deposits or vegetation, and therefore, inaccessible for scientific research. Atlas of Deformed and Metamorphosed Rocks from Proterozoic Orogens provides a range of lithologies and associated structural features that are captured from well-exposed sections of Proterozoic orogenic belts of India, Sri Lanka, Madagascar, Western Australia, Southern Africa, the Arabian Shield, and Antarctica. The Atlas provides an important source of information and reading for a broad range of earth scientists, graduate and undergraduate students, researchers, academicians and other professionals. This will also be useful for specialists in structural geology, petrology, geochemistry, geochronology, isotope studies, exploration geology, economic geology, and geophysics. Features 400 full-color photographs representing typical lithologies and associated structural and metamorphic features from different Proterozoic orogens Includes line drawings of the photographs for clarity and better understanding Presents regional geologic maps from Proterozoic orogens worldwide

Evidence for Early Proterozoic north-verging folding and thrusting in the continental foreland of the Penokean orogen is present in two widely separated areas in northern Michigan. In the eastern part of the exposed orogen, asymmetric to over-turned folds in the Early Proterozoic Michigamme Formation suggest an initial (D1) phase of possibly north verging thin-skinned deformation. A second phase (D2 ) is characterized by a more thick skinned deformation consisting of northward thrusting of Archean gneiss and overlying Early Proterozoic quartzite along ductile thrust faults. Crosscutting shear zones indicate a third phase (D3 ) of deformation involving east- northeast thrusting of Archean gneiss. Thick-skinned deformation D2 and D3 phases include spaced fracture cleavage, kink folds, and lineations in D1, foliation surfaces. Near the west end of the exposed orogen in Michigan, bedding-cleavage relationships in the Early Proterozoic Tyler Formation also indicate northward tectonic transport. These structures, which are interpreted as D1 lie along the north edge of the Archean Puritan batholith and associated Archean greenstone. The north-verging structures in the northern Michigan segment of the Penokean orogen were formed approximately 1,850 Ma during collision of the Wisconsin magmatic terranes with the continental foreland of Michigan, Wisconsin, and Minnesota.

The BIRPS Atlas presents the 100 deep seismic reflection profiles collected around the British Isles by the BIRPS Group (BIRPS - British Institutions Reflection Profiling Syndicate) at desk-top scale.

T is atlas is intended primarily for anybody who is in-some background for the arrangement of how the terested in basic geology of Africa. Its originality lies atlas was done. T e second chapter is devoted to the in the fact that the regional geology of each African history of geological mapping in Africa, necessary nation or territory is reviewed country-wise by maps for a fuller appreciation of why this work in Africa is and text, a view normally not presented in textbooks worth doing. Chapter 3 provides an executive s- of regional geology. It is my belief, that there has long mary on the stratigraphy and tectonics of Africa as a been a need in universities and geological surveys, whole, i. e. in the context of no political boundaries. both in Africa and in the developed world, for sum- T e main part of the atlas lies in Chapter 4, where in marizing geological maps and an accompanying basic alphabetical order each African country or territory text utilising the enormous fund of knowledge that is presented by a digitized geological overview map has been accumulated since the beginning of geologi- and an accompanying text on its respective strat- th cal research in Africa in the mid-19 century. I hope raphy, tectonics, economic geology, geohazards and that, in part, the present atlas may satisfy this need. geosites. A short list of relevant references is also a- ed.

In December, 1987, Project 233 of the International Geological Correlation Pro gram hosted an international conference in Nouakchott, Mauritania. Discussions were focused on the "Tectonothermal Evolution Of The West Mrican Orogens And Circum-Atlantic Terrane Linkages". A wealth of new information was pre sented during the conference, and it was apparent that the time was appropriate to prepare a systematic volume dealing with the geology of northwest Mrica. The present volume is an outgrowth of this conference, but is not merely a compilation of the papers presented in Nouakchott. Instead, it represents a coordinated vol ume designed to present a balanced, comprehensive view of our present under standing of West Mrican geology and potential correlations in other Circum-At lantic Paleozoic orogens. We sincerely appreciate the efforts of all the reviewers whose comments have greatly helped to improve the quality of this volume. We also thank the various contributors for their diligence and perseverance in manuscript preparation. The calibre of the present volume is a reflection of their labor. Athens/Marseille, Autumn 1990 R. D. DALLMEYER J. P. LECORCHE Contents Chapter 1 Introduction . . . . . . . . . . . . . . . 3 R. D. DALLMEYER and J. P. LECORCHE Chapter 2 Geophysics and the Crustal structure of West Africa 9 J. ROUSSEL and A. LESQUER Chapter 3 Crystalline Basement of the West African Craton . . . . . . . . . . . . .. . . 31 .

This encyclopedia includes a two-volume index, a 12-volume Micropaedia (Ready reference), a 17-volume Micropaedia (Knowledge in depth), and the Propaedia.