New Jersey Highlands

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Conventional thought had been that the old rock of the Green Mountains, the Berkshires, the New Jersey Highlands, the Catoctin Mountains, and the northern Blue Ridge was in place, firmly rooted-autochthonous, as geologists are wont to say. It may have been crushed and pounded in the various orogenies, and metamorphosed, too, but it was nonetheless thought to be securely glued where it first had formed as rock. The belt was supposed to have been the fixed starting block from which, somehow, thrusting had proceeded northwest. The idea had come up through the Old Geology and been incorporated into the substance of plate tectonics. Then, in i979, Vibroseis rumbled into the country and showed that from Quebec to the Blue Ridge the entire belt was deracinated. The Great Smokies and the Skyline Drive, Camp David and the Reading Prong, the Berkshires and the Green Mountains-all of it had moved, at least a few tens of miles and as much as a hundred and conference room amsterdam seventy-five miles, northwest. Using the new data, Leonard meticulously drew a palinspastic reconstruction of North American rock, showing it as it had appeared before it was shoved and deformed. He chose a cross section that had been shot more or less from Knoxville to Charleston and out to sea. The reconstruction showed that the rock of the Ridge and Valley-the folded-and-faulted, deformed Appalachians-had been squeezed so much that its breadth had been reduced about sixty miles. The supposedly rooted Blue Ridge had been moved inland from what is now the coast. Rock of the present Piedmont had come from three hundred miles out in the present sea. This left Africa out in the conference room rotterdam cold and plate-tectonic theory in no small need of a substitute for what had been-and in many classrooms would continue to be-the world’s most “classical” example of a continent-tocontinent suture.