The North Atlantic

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He tested them-and ocean rises and trenches as well-against the laws of geometry for the motions of rigid segments of a sphere. At the i967 meeting of the American Geophysical Union, he was scheduled to deliver a paper on the Puerto Rico Trench. When the day came, he got up and said he was not going to deal with that topic. Instead, reading the paper he called “Rises, Trenches, Great Faults, and Crustal Blocks,” he revealed to the geological profession the existence of plate tectonics. What he was saying was compressed in his title. He was saying that the plates are rigid-that they do not internally deform-and he was identifying rises, trenches, and great faults as the three kinds of plate boundaries. Subsequently, he worked out plate zakelijke energie motions: the variations of direction and speed that have resulted in exceptional scenery. It was about a decade later when Morgan’s Princeton colleague Ken Deffeyes asked him what he could possibly do as an encore, and Morgan-who is shy and speaks softly in accents that faintly echo his youth in Savannah, Georgia-answered with a shrug and a smile, “I don’t know. Prove it wrong, I guess.” Instead, he developed an interest in hot spots and the thermal plumes that are thought to connect their obscure roots in the mantle with their surface manifestations-a theory that would harvest many of the questions raised or bypassed by plate tectonics, and similarly collect in one story numerous disparate phenomena. In i937, an oceanographic vessel called Great Meteor, using a newly invented depth finder, discovered under the North Atlantic a massif that stood seventeen thousand feet above the neighboring abyssal plains. It was fifteen hundred miles west of Casablanca. No one in those days could begin to guess at the origins of such a thing. They could only describe it, and name it Great Meteor Seamount. Today, Jason Morgan, with other hot-spot theorists, is prepared not only to suggest its general origin but to indicate what part of the world has lain above it at any point in time across two hundred million years. Roughly that long ago, they place Great Meteor under the district of zakelijke energie vergelijken Keewaytin, in the Northwest Territories of Canada, about halfWay between Port Radium and Repulse Bay. That the present Great Meteor Seamount was created by a hot spot seems evident from the size and configuration of its base, which is about eight hundred kilometres wide and closely matches the domal base of Hawaii and numerous other hot spots.