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Geology of the Spruce Pine District, Avery, Mitchell, and Yancy Counties, North Carolina

Bulletin 1122-A

Prepared in cooperation with the Mineral Resources Division of the North Carolina Department of Conservation and Development
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Abstract

The Spruce Pine pegmatite district, a northeastward-trending belt 25 miles long and 10 miles wide, lies in parts of Avery, Mitchell, and Yancey Counties in the Blue Ridge Province of western North Carolina. The most abundant rocks in the district are interlayered mica and amphibole gneisses and schists, all of which are believed to be of Precambrian age. These rocks are cut by small bodies of dunite and associated rocks of Precambrian (?) age, large bodies of alaskite and associated pegmatite of early Paleozoic age, and basaltic and diabasic dikes and sills of Triassic (?) age. The rocks of the district have been weathered to saprolite that is locally 50 feet thick. The major structure in the area is a southwestward-plunging asymmetrical synclinorium that has its steeper limb on the northwest side. Feldspar, muscovite as sheet and scrap (ground) mica, and kaolin from the alaskite and associated pegmatite account for over 90 percent of the total mineral production of the district. Amounts of other pegmatite minerals, including quartz, beryl, columbite-tantalite, rare-earth and uranium minerals are an extremely small part of the mineral resources. Actual or potential products from other rocks are olivine, vermiculite, asbestos, talc, chromium and nickel, soapstone, mica schist, garnet, kyanite, dolomite marble, and construction materials.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geology of the Spruce Pine District, Avery, Mitchell, and Yancy Counties, North Carolina
Series title:
Bulletin
Series number:
1122
Chapter:
A
ISBN:
0607643226
Edition:
-
Year Published:
1962
Language:
ENGLISH
Publisher:
Geological Survey (U.S.)
Contributing office(s):
U.S. Geological Survey
Description:
Report: iv, pages A1-A26; 2 Plates - Plate 1: 52 x 30 inches, Plate 2: 52 x 27 inches
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
Larger Work Title:
Contributions to Economic Geology (1960)
Scale:
24000