New Developments In The Appalachian Caledonian Variscan Orogen

"This volume provides a comprehensive overview of our understanding of the evolution of the Appalachian-Caledonian-Variscan orogen. It takes the reader along a clockwise path around the North Atlantic Ocean from the U.S. and Canadian Appalachians; to the Caledonides of Spitsbergen, Scandinavia, Scotland and Ireland; and thence south to the Variscides of Morocco"--

The classical Appalachian, Caledonian, Hercynian, and Mauritanide orogens are now only segments of a once-continuous Paleozoic mountain belt which has been fragmented during Mesozoic-Cenozoic formation of the North Atlantic Ocean. These segments are major parts of the countries surrounding the North Atlantic - most of which are members of NATO. The aim of this NATO conference was to evaluate these fragments in terms of their pre-Mesozoic positions, and to attempt a synthesis of their geologic evolution on an international and orogen-wide scale. Geologists who have studied these scattered remnants have been separated by both geography and discipline. Orogen-wide syntheses have beeen attempted in the past by individuals who are specialists not only in discipline but also in geography; therefore, these attempts have not been satisfactory to everyone. This conference brought together the foremost specialists in different disciplines from each country. They attempted to teach other specialists, not only in their own fields, but in other disciplines, about regional variations and particular problems. The resulting international cross-fertilization, both within and between speciaLties, enriched individual workers and helped to provide a multi-disciplinary overview of the orogen.

This book contains a comprehensive field guide, including detailed itineraries and supporting data, to the Geology of Western Ireland, a classic site for world geology. It facilitates study into the rock record of the Neoproterozoic ‘birth’ to the Devonian ‘death’ of the Iapetus Ocean along the Laurentian (North American) margin. The enormous variety of lithologies and processes available for study in this spectacularly exposed region include: fluviatile to deep-sea sediments; layered ultramafic intrusions to reverse zoned granite batholiths; zeolite to eclogite facies metamorphic assemblages; continental rifting; subduction processes; island arc evolution; arc-continent collision; Andean margin development; and continent-continent collision. An introduction to the geology, that includes information relevant to the planning and execution of field trips in the region, is followed by nine chapters each providing the necessary background, field itineraries, exercises and points for debate, covering: the Laurentian basement and Neoproterozoic cover of North Mayo, Sligo, the Ox Mountains and Connemara; the metamorphic nappes and syn-orogenic intrusions of the Ordovician Grampian Orogeny; the Cambro-Ordovician subduction-accretion complex of Clew Bay; the obducted Ordovician fore-arc basin of South Mayo; the post-subduction flip late-Ordovician of South Connemara; the Silurian successor basins deformed during the final closure of the Iapetus Ocean; the late to post-orogenic Devonian sediments; the Devonian Granite batholiths ; and the post-orogenic Carboniferous cratonic sediments. Two final chapters summarise: the current tectonic interpretation of this region; areas for future research; and the extensive sources of geochemical and geophysical data.

"The Appalachians constitute one of Earth's major tectonic features and have served as a springboard for innovative geologic thought for more than 170 years. This volume contains 36 original papers reporting the results of research performed throughout nearly the entire length and breadth of the Appalachian region, including all major provinces and geographical areas. Memoir 206 was designed to commemorate the (near-)fortieth anniversary of the publication of the classic Studies of Appalachian Geology volumes that appeared just prior to the application of plate tectonic concepts to the region. Contributions concerning structural evolution, sedimentation, stratigraphy, magmatic processes, metamorphism, tectonics, and terrane accretion illustrate the wide range of ongoing research in the area and collectively serve to mark the considerable progress in scientific thought that has occurred during the past four decades."--pub. desc.

"This Memoir focuses on 7 'turning points' that had specific and lasting impacts on Laurentian evolution: The Neoarchean, characterized by cratonization; the Paleoproterozoic and the initial assembly of Laurentia; the Mesoproterozoic southern margin of Laurentia; the Midcontinent rift and the Grenville orogeny; (5) the Neoproterozoic breakup of Rodinia; the mid-Paleozoic phases of the Appalachian-Caledonian orogen; and the Jurassic-Paleogene assembly of the North American Cordillerar"--

Summaries of the major features of the geology of North America and the adjacent oceanic regions are presented in 20 chapters. Topics covered include concise reviews of current thinking about Precambrian basement, Phanerozoic orogens, cratonic basins, passive-margin geology of the Atlantic and Gulf Coast regions, marine and terrestrial geology of the Caribbean region and economic geology.

This volume focuses on the Canadian Appalachian region. The chapter on the East Greenland Caledonides stands alone and there is no attempt to integrate the geological accounts of the two far removed regions. Rocks of the Canadian Appalachian region are described under four broad temporal divisions: lower Paleozoic and older, middle Paleozoic, upper Paleozoic, and Mesozoic. The rocks of these temporal divisions define geographic zones, belts, basins, and graben, respectively. The area is of special interest because so many modern concepts of mountain building are based on Appalachian rocks & structures.