Plate tectonics

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The experience was cautionary, to say the least. It did not close her mind to plate tectonics, but it opened a line of suspicion and made her skeptical of the theory’s insistent universality. Her discomfort varies with distance from the mobile ocean floors. She likes to describe herself as a “protester.” The protest is not so much against the theory itself as against excesses of its application-up on the dry land. “A number of these people took very interesting ideas that apply to ocean floors and tried to apply them to everything,” she remarked. “They tried to extrapolate plate tectonics through all geologic time. I don’t know that that holds. My husband has blown some of their ideas apart.” Leonard Harris, sometimes co-working space tilburg known as Appalachian Harris, was very much a protester, too. Tragically, he died in i982, a relatively early victim of cancer and related trouble. He was a genial and softspoken, almost laconic man with a lean figure that had walked long distances without the help of trails. He liked to build ideas on studied rock, and was not easily charmed by megapictures global in their sweep. He referred to the long deep time before the Appalachian orogenies as “the good old days.” With regard to plate tectonics, he looked upon himself as a missionary of contrary opinion-not flat and rigid but selective, where he had knowledge to contribute. His wife has compared him to Martin Luther, nailing theses to the door of the castle church. For some years he assisted oil companies in the training of geologists and geophysicists in southern-Appalachian geology, and in┬áreturn the companies made available to him their proprietary data from seismic investigations of the Appalachian crust. Later on, these data were supplemented by the seismic thumpings of the U.S.G.S. and co-working space groningen several university consortiums, whose big trucks go out with devices that literally shake the earth while vibration sensors record wave patterns reflected off the rock deep below. The technique is like computed axial tomography-the medical CAT scan. The patterns reveal structure. They reveal folds, faults, laminations, magmatic bodies both active and cooled. They report the top of the mantle.

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