Location: 40o 44' 00" N, 116o 01' 08" W.
Carlin Canyon, a few miles east of the town of Carlin, Nevada, is a classic place that reveals just how complex the Earth's history is. On the left side of the image are vertical layers of conglomerate from the Mississippian Period, about 300 million years ago. Above them, on the distant hilltop, are younger limestone layers from the next period, the Pennsylvanian, that slope, or dip, to the east (right).
Beginning about 300 million years ago, the western United States was subject to repeated episodes of crustal disturbance and mountain building. During one mountain building episode, erosion stripped rocks off the mountains and deposited them as beds of sand and gravel. Those deposits were tilted and eroded, then a sea covered the eroded surface with limestone. Later on, a second crustal disturbance tilted the rocks again.
A small stream, the Humboldt River, flows along the valley floor. Even though it is a very small stream today, it was larger in the past and cut through the mountains as they were being uplifted. At one time it probably flowed to the Pacific, but uplift of the Sierra Nevada in California cut the river off from its former outlet, and today it flows across Nevada and ends in a series of dry lakes near Reno. As small as the stream is, it provides an easy route across the mountains of Nevada and was followed first by Indians, then by covered wagons and the transcontinental railroad. Modern Interstate 80 follows the river for much of its length.
Created 30 June 2009, Last Update 14 December 2009
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