The thermal evolution of mountain belts is recorded inthe distribution, origin and ages of magnatism. In this volume, petrologic, isotopic and geochemical evidence is presented to highlight the contribution of igneous rocks to the evolution of the Appalachian Orogen in both Canada and the United States. These papers emphasize the use of modern geochemical and petrologic data to discriminate the sources yielding magmas, and thus the nature of the crust and mantle.

"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.

Consisting of papers that have appeared recently in International Geology Review, Middle American Terranes, Potential Correlatives, and Orogenic Processes focuses on Middle American terranes in which tectonic processes, including flat-slab subduction, for orogenic development are examined at various times since the late Mesoproterozoi

"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"--