Excavation

Gerelateerde afbeelding

To the north and south of it, excavation has been deep and wide, and the mountain front is of formidable demeanor. Yet this one piece of the Great Plains-extremely narrow but still intact-extends like a finger and, as ever, touches the mountain core: the pink deroofed Precambrian granite, the top of the range. At this place, as nowhere else, you can step off the Great Plains directly onto a Rocky Mountain summit. It is known to geologists as the gangplank. Now the Bronco began to rise through the snow, and Love remarked that we were on the gangplank. The land fell away on either side, and in the low visibility we seemed indeed to be on a plank going up into the sky. As we continued to climb, the strip of earth became narrower and narrower. We pulled over onto the shoulder, shut off the motor, and squinted. We appeared to be on a bridge-built of disassembled Rockies and travelled ash-crossing a great excavation through Rapping veils of snow. “There are twelve inches of precipitation per annum here, and it’s mostly snow,” he said. “The mean zakelijke energie vergelijken temperature is thirty-eight degrees. The growing season is less than ninety days. Conditions are about the same in this part of Wyoming as at the Arctic Circle.” With that, we gave up the geology and crawled off to his home in Laramie, defeated by the snow. We went back to the gangplank in clear weather. It was half a mile long. To the north and south, the land fell away along the mountain front in profound excavation of the sediments that once had been there. The excavation had exposed the broken, upturned ends of Pennsylvanian sandstones, dipping steeply eastward and leaning on the mountains. They rested there like lumber stood against a barn. These red sandstones lean against the Laramie Range on both sides. By themselves, they tell the story of the Laramide Orogeny, for they are a part of what was deroofed. They are a part of the zakelijke energie Paleozoic package that once rested Rat on the deep Precambrian granite. They are thought by some to have been Pennsylvanian beach sands. Whatever they may have been, they were indubitably horizontal, and for roughly two hundred and fifty million years remained horizontal while layer after layer of sediment accumulated above them, finally including the floors of the Cretaceous seas.

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