Geology of the western Great Smoky Mountains, Tennessee

Abstract

Rocks of the Great Smoky Mountains, a part of the Blue Ridge province, have been thrust northwestward over younger more easily eroded rocks of the Valley and Ridge province along the Great Smoky fault. The overridden rocks in a nearly homoclinal sequence northwest of the fault are also exposed in windows eroded through its upper plate farther southeast. The homoclinal sequence consists of Lower Ordovician to Mississippian rocks. The Mississippiau rocks, about 1.500 feet thick, are limestone, shale, and sandstone of the Greasy Cove Formation and siltstone, sandstone, and conglomerate of the Grainger Formation. The Chattanooga Shale represents the uppermost part of the Devonian System. The Chattanooga rests directly upon the Bays Formation of Middle Ordovician age; neither rocks of older Devonian age nor any of Silurian or Late Ordovician ages are present. The Middle Ordovician sequence, about 7,500 feet thick, consists from the top down of red mudrock of the Bays Formation, calcareous shale and sandstone of the Sevier Formation, quartzose calcarenite of the Chota Formation, an older calcareous shale and sandstone of the Tellico Formation, dark calcareous shale of the Blockhouse Shale which includes a sandstone and a limestone member, and at the base, the Lenoir Limestone. Disconformably beneath the Lenoir are interbedded limestone and dolomite in part equivalent to the Mascot Dolomite of Early Ordovician age. Blockhouse Shale and Lenoir Limestone represent the Middle Ordovician in the Tuckaleechee Cove window. Older rocks here are partly correlatives of the Mascot Dolomite, but some both here and in the Cades Cove window have fossils that occur in older Ordovician formations of the Knox Group. Rocks of Early Cambrian, Early Cambrian(?), and late Precambrian age, including the Chilhowee Group and the Ocoee Series, form the upper plate of the Great Smoky fault. Thrust faults cut this plate into several parts, each with its own rock sequence. The northwesternmost of these sequences, that of Chilhowee Mountain, contains the youngest rocks of the upper plate red shale and sandstone of the Rome Formation (Lower Cambrian) underlain by the Shady Dolomite. The Chilhowee Group beneath, with Lower Cambrian fossils in the Helenmode Formation and the Murray Shale, is classed as Early Cambrian and Earl.v Cambrian (?) in age. The Chilhowee Group consists of siltstone and calcareous and glauconitic sandstone of the Helenmode Formation, Hesse Quartzite, Murray Shale, Nebo Quartzite, Nichols Shale, and the Cochran Formation. Beneath the Cochran, micaceous siltstone, sandstone, and conglomerate, interbedded in various proportions, are assigned to the Sand-FIGURE 1. Index map showing location of Great Smoky Mountains National Park and the area of this report.

Geology of the Great Smoky Mountains National Park, Tennessee and North Carolina

“…ical Survey Professional Papers (Hamilton, 1961;Hadley and Goldsmith, 1963;King, 1964;Neuman and Nelson, 1965).…”

Mineral resources of the Citico Creek Wilderness Study Area, Monroe County, Tennessee

“…Unconsolidated alluvial deposits of Quaternary age are found locally in some major stream drainages. Precambrian rocks northeast of the map area and just north of the Little Tennessee River in the western part of the Great Smoky Mountains National Park have been subdivided by Neuman and Nelson (1965). More recently, Merschat and Wiener (1973) (Wiener and Merschat, 1978) designated them the Farner, Boyd Gap, and Buck Bald Formations, respectively.…”

Bedrock geology and mineral resources of the Knoxville 1° x 2° quadrangle, Tennessee, North Carolina, and South Carolina

“…Later work in the western part of the Blue Ridge by Hamilton (1961), Hadley and Goldsmith (1963), King (1951, 1964a andb), Neuman and Nelson (1965), Hadley and Nelson (1971), and, in the Grandfather Mountain window area, by Bryant and Reed (1970) has been the basis for many current concepts of stratigraphy and structure.…”