The Appalachian

Afbeeldingsresultaat voor site:ilocate.nl

Bermuda came through there like a train coming out of a tunnel. Or so it would appear. In the Campanian age of late Cretaceous time, when Great Meteor was in mid-Atlantic, Bermuda was under the Great Smoky Mountains. The Appalachian system consists of parallel bands of kindred geology sinuously winding from Newfoundland to Alabama, where they disappear under the sediments of the Gulf Coastal Plain. Why this long ropy package would stand high in two places and sink low in others is not explained by plate tectonics. It can be explained by hot spots. Great Meteor and Cape Verde seem to have lifted New England’s high zakelijke energie mountains, Bermuda the Smokies. Uplift accelerates erosion. The rock of the Permian period-the last chapter in the Appalachian mountain-building story-has been removed everywhere in eastern America except in West Virginia and nearby parts of Ohio and Pennsylvania, halfWay between the hot-spot tracks, halfWay between New Hampshire and North Carolina. Because plate motions have shifted over time, the tracks of all hot spots, ancient and modern, form a plexus on the face of the earth. Untouched areas between lines often prove to be continental basins-the Michigan Basin, the Illinois Basin, the Mississippi Embayment, the Williston Basin-while the rims of the basins are structural arches lined up on the tracks of the hot spots. Morgan thinks the large continental basins may have been cre8.ted when hot spots elevated the edges. The Great Meteor track runs between the Hudson Bay Basin and the Michigan Basin. A Paleozoic hot spot seems to have made the Kankakee Arch, which separates the Michigan and Illinois basins. The Bermuda track zakelijke energie vergelijken runs between the Illinois Basin and the Mississippi Embayment. “Every basin gets missed,” comments Morgan, with his hand on a map. “I don’t think that’s a coincidence.” Bermuda made the Nashville Dome. It lifted the Ozark Plateau, in middle Cretaceous time. “How much erodes off the top when a hot spot lifts something up depends on the durability of what’s there,” Morgan goes on. “If it’s coastal mush, or Mississippi River mush, it goes quickly and in great volume. If it’s quartzite, it resists. The resistant stuff stands up higher.”