The timing of Acadian orogenesis in Maine is reassessed, on the basis of a new Silurian-Devonian time scale, new U/Pb and 40Ar/39Ar ages of Acadian plutons, new conodont and palynomorph ages of strata that constrain the age of deformation, and published information. This analysis shows that the Acadian deformation front migrated some 240 km (present distance) from southeast to northwest during a span of about 40 million years from Late Silurian to Middle Devonian time.

"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"--

Dedicated to Bob Hatcher, this Memoir explores linkages between tectonic processes through a series of field-, numerical- and laboratory-based studies, concentrating on feedback mechanisms within ancient and evolving orogens by which individual or linked tectonic processes may influence or predetermine the operation of other processes in space and time. Case studies cover a wide range of ancient to modern orogens: the Svecofennian of southern Finland, the Gyeonggi Massif of Korea, the Caledonides of northern Scotland, the Variscan of the East European craton, the Appalachians of the eastern United States, the European Alps and Dinarides, north Cascades of the northwestern United States, and the Himalaya. Emphasis is placed on integration between data sets developed from a wide range of analytical approaches, including: field mapping, seismic reflection profiling, strain analyses, petrology, isotopic dating, and numerical modeling-based studies of thermal evolution associated with tectonic processes such as thrust-related burial and exhumation.