Selasa, 13 Desember 2011

The Wichita Mountains

Rising from the flat terrain of southern Oklahoma, northwest of Lawton, ridges of igneous and metamorphic rock trend northwest to southeast. Thirty miles long, these rock formations originated in a rift zone that developed from the late Precambrian Era into the Cambrian Period, some 550-600 million years ago. Though the rifting process was aborted, plutons of granite, intrusions of gabbro and deposits of rhyolite were encased within and atop the surrounding crust and, over the next 20 million years, were covered by layers of younger Paleozoic sediments.

During the Pennsylvanian Period, about 325 million years ago, the continents began to merge into Pangea. The collision of North America and Africa crumpled up the Southern Appalachians and the docking of South America extended that collision zone toward the west, lifting the Ouachita and Wichita Mountains. Erosion coincided with this uplift and continues today; having carried away the overlying and encasing sediments, wind and water have left behind outcrops of the ancient rock that formed within the Cambrian rift. Of course, the ridges of the Wichita Mountains, like all ranges on this planet, will eventually wear down to a level plain, their aprons of debris carried off to the sea or dispersed by the wind.

Wichita Mountains NWR protects a portion of this scenic landscape, providing habitat for bison, elk and the more common wildlife of southern Oklahoma. Several of the peaks rise above 2400 feet, offering a cool retreat during the summer months and attracting a wide variety of birds to their oak woodlands. From I-44, about 8 miles north of Lawton, head west on Route 49; the refuge will be approximately 12 miles ahead.

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