The morning shadow

Afbeeldingsresultaat voor

It stands in the morning shadow of the Annieopsquotch Mountains, of the Green Mountains, of the New Jersey Highlands, of the Berkshire, Catoctin, and Great Smoky Mountains, which are fraternal in structure and composition and are all of Precambrian age. The lookoff where we stood was a part of that Appalachian complex. It was crystalline rock above a thousand million years old-and the rock in the valley was younger, and in the Kittatinny younger still. (Geologists avoid the word “billion” because in one part and another of the Englishspeaking world the quantity it refers to differs by three orders of magnitude. A billion in Great Britain is a million million.) We were looking from the New Jersey Highlands into another segment of the cordillera-the beginnings of the physiographic Ridge and Valley Province, the folded-and-faulted deformed Appalachians, the long ropy ridges of the eastern sinuous welt, which Edmund Wilson had once written off as “fairly unimportant creases in the earth covered with trees.” “Geology repeats itself,” Anita remarked, and she went on to say that anyone who could understand the view before us would have come to flexplek huren leeuwarden understand in a general way the Appalachians as a whole-that what we were looking at was the fragmental evidence and low remains of alpine massifs immeasurably high and wide, massifs which for the most part had stood behind us to the east, and were now largely disintegrated and recycled into younger rock that is tens of thousands of feet deep and wedges out to the west in everdiminishing quantity until what covers Ohio is a thin veneer. The appearance of a country is the effect primarily of water, running off the landscape, cutting out valleys, dozing wantonly as glacier ice. The sculpturing is external. But it is influenced and can even be controlled by the rock within: by the relative strength, not to mention the solubility, of successive strata, and by the folds and faults-the structure-that the rock has been given. Figuring out the Appalachians was Problem i in American geology, and a difficult place to begin, for it was scarcely a matter of layer-cake legibility, like the time scale in the walls of the Grand Canyon. It was flexplek huren eindhoven a compressed, chaotic, ropy enigma four thousand kilometres from end to apparent end, full of overturned strata and recycled rock, of steep faults and horizontal thrust sheets, of folds so tight that what had once stretched twenty miles might now fit into five.

Geef een reactie

Het e-mailadres wordt niet gepubliceerd. Verplichte velden zijn gemarkeerd met *