The Appalachians, with a deeply rugged topography due to fluvial action, spreads over 1,800 miles from the Canadian border to the southern state of Alabama. Relatively low elevation mountains characterize this range, reaching its highest point on Mount Mitchell (2,037 m).
In its northern part of the Appalachians, there’s evidence of the Quaternary glaciations, such as the Great Lakes. This range is further divided into two sections: the Smokey Mountains and the Blue Ridge Mountains.
Sedimentary deposits in the Appalachian Range vary from Paleozoic rocks in the north to metamorphic and granite in the south (Blue Ridge). These are features that reveal that the Blue Ridge Mountains were formed before the northern part of the Appalachian Range.
Different features characterize each of these mountain ranges. The chain of the Smoky Mountains (in contrast with the next highest, the Blue Ridge) is more continuous, more elevated and more regular in their direction and height, and very uniform up five thousand in 1700 to nearly six feet.
The Smoky Mountains are the remnants of an older range. Three hundred million years ago, layers of limestone sediment were added to already existing sedimentation resulting in the beginning of the mountain formations. The mountain structures grew to great elevation with the shifting and tilting of the underlying metamorphic rock. The magnitude of erosion due to water run-off has reshaped and greatly diminished these mountains’ elevations. Most of the rocks in the Smoky Mountains date to the Precambrian Age.
Blue Ridge Mountains
The southern part of the Appalachians is considered the Blue Ridge; it is composed of many low-lying slightly separated elevations. The range is remarkably uniform in shape and elevation. Its origination dates back to the earth’s movements about 270 years ago. During this time rocks were pushed in a westerly direction resulting in accumulation that formed the Appalachians. With the years, erosion has deteriorated these mountains to a fragment of their original size and only the cores are evident today.
The Blue Ridge Mountains have a crystalline foundation and its basement comprises gneiss and schist from volcanic rock. This indicates that volcanic flow may have been partly responsible for the formation of these mountains.
Unesco – Retrieved 1/14/2012 from: http://whc.unesco.org/en/list/304
The New Georgia Encyclopedia – Retrieved 1/14/2012 from: http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-2141
National Park Service, u.S. Dept of the Interior – Retrieved 1/14/2012 from: http://www.nps.gov/grsm/naturescience/geology.htm
Great Smoky Mountains Geology – Retrieved 1/14/2012 from: http://magsfieldguide.blogspot.com/2007/04/great-smoky-mountains-geology.html