Bedrock Geology and Mineral Resources of the Knoxville 1°x2° Quadrangle, Tennessee, North Carolina, and South Carolina By G.R. ROBINSON, Jr., F.G. LESURE, J.I. MARLOWE II, N.K. FOLEY, and S.H. CLARK U.S. GEOLOGICAL SURVEY BULLETIN 1979 U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN/ Jr./ Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government UNITED STATES GOVERNMENT PRINTING OFFICE: 1992 For sale by Book and Open-File Report Sales U.S. Geological Survey Federal Center, Box 25286 Denver, CO 80225 Library of Congress Cataloging in Publication Data Bedrock geology and mineral resources of the Knoxville 1°x2° quadrangle Tennessee, North Carolina, and South Carolina / by G.R. Robinson, Jr. ... [etaf.]. p. cm.-(U.S. Geological Survey bulletin ; 1979) Includes bibliographical references. Supt. of Docs. no.: I 19.3:1979 1. Geology—Tennessee. 2. Geology—North Carolina. 3. Geology—South Carolina. 4. Mines and mineral resources—Tennessee. 5. Mines and mineral resources—North Carolina. 6. Mines and mineral resources- South Carolina. I. Robinson, G.R. II. Series. QE75.B9 no. 1979 [QE 165] 557.3 s-dc20 91-592 [577.68] CIP CONTENTS Abstract 1 Description of the Area 2 Geography 2 National Park, National Forest, and Indian Lands 5 Wilderness, Wilderness Study, and Roadless Areas 5 Geology of the Knoxville Quadrangle 7 Introduction 7 Previous Work 7 Geologic Overview 7 Inner Piedmont Lithotectonic Belt 10 Blue Ridge 13 East Flank Blue Ridge Lithotectonic Belt 14 Helen Thrust Sheet 15 Amphibolitic Basement Complex and Richard Russell Thrust Sheet 15 Tallulah Falls Thrust Sheet 16 Central Blue Ridge and Proterozoic Portion of the West Flank Blue Ridge 17 Ocoee Supergroup 17 Murphy Belt 18 Valley and Ridge and Paleozoic Portion of the West Flank Blue Ridge 19 Late Proterozoic to Early Ordovician 19 Middle Ordovician to Devonian 20 Late Devonian and Mississippian 20 Structure 20 Metamorphism 20 Geologic Summary 22 Mineral Resources 26 Introduction 26 Construction Materials 26 Cement 27 Common Clay and Shale 28 Crushed Stone 28 Dimension Stone 29 Lightweight Aggregate 30 Limestone and Dolomite 30 Sand and Gravel 30 Industrial Minerals 31 Mineral Commodities Related to Mafic and Ultramafic Rocks 31 Asbestos 39 Chromite 39 Corundum 39 Nickel 40 Olivine 40 Platinum-Group Elements 40 Soapstone and Talc 40 Vermiculite 41 Mineral Commodities Related to Granite and Pegmatite 42 Pegmatite Deposits 45 Pegmatite Districts 46 Spruce Pine District 46 Woodlawn District 46 Buncombe District 46 Bryson City District 47 Franklin-Sylva District 47 Cashiers District 47 Feldspar 47 Kaolin 48 Mica 48 Quartz 49 Zircon 49 Other Industrial Minerals 49 Barite 49 Fluorspar 51 Garnet 51 Gem Stones 52 Graphite 53 Kyanite Group of Minerals 53 Phosphate 54 Rutile 55 Oil and Gas Potential 55 Metallic Resources 56 Base Metals (Copper, Lead, Zinc, and Iron) 56 Precious Metals (Gold, Silver, and PGE's) 60 Manganese 61 Vanadium 61 Thorium and Rare-Earth Elements 61 Uranium 62 Tungsten 62 Acknowledgments 62 References Cited 62 PLATES [Plates are in pocket] 1. Preliminary bedrock geologic map of the Knoxville l°x2° quadrangle, Tennessee, North Carolina, and South Carolina 2. Paleozoic metamorphic facies map of the Knoxville l°x2° quadrangle FIGURES 1-2. Maps showing: 1. Location of the Knoxville l°x2° quadrangle, with State and county boundaries 2 2. Physiographic provinces of the Appalachian region 3 3. Knoxville l°x2° quadrangle showing available 7 1/2-min topographic maps 4 4. Areas of National Forest, National Park, and Indian lands in the Knoxville \°x2° quadrangle, with wilderness, wilderness study, and roadless areas 6 5. Areal coverage of geologic mapping at a scale of 1:24,000 or larger in the Knoxville quadrangle 12 6. Areal coverage of geologic mapping at a scale of 1:25,000 to 1:62,500 in the Knoxville quadrangle 12 7. Areal coverage of geologic mapping at a scale of 1:63,360 to 1:125,000 in the Knoxville quadrangle 12 8. Named faults and windows of the Knoxville quadrangle 13 9. Generalized lithotectonic map of the Knoxville quadrangle 14 10. Subunits of the east flank of the Blue Ridge 16 11. Distribution of Middle Proterozoic crystalline rock and rocks of the Late Proterozoic Ocoee Supergroup in the Blue Ridge 17 12. Age of metamorphism 23 13. Generalized tectonics of the Knoxville quadrangle 24 14. Areas of limestone, dolomite, and marble resources in the Knoxville quadrangle 29 15. Localities of rock samples analyzed for platinum-group elements, southern part of the Knoxville quadrangle 42 16. Pegmatite districts and outlying pegmatites in the Southern Appalachians 44 17. Areas containing pegmatite resources and granite suitable for feldspar production in the Knoxville quadrangle 45 18. Areas containing resources of garnet, graphite, kyanite, quartz, rutile, sillimanite, and zircon in the Knoxville quadrangle 50 19. Areas ofbarite and fluorite resources in the Knoxville quadrangle 51 20. Areas having a low potential for phosphate deposits 54 21. Location of detrital monazite belts in the Knoxville quadrangle and vicinity 62 TABLES 1. Ages of igneous rocks in the Knoxville quadrangle and vicinity, by lithotectonic belt 8 2. References for geologic map coverage as shown in figures 5, 6, and 7 11 3. Mineral commodities produced in or near the Knoxville l°x2° quadrangle by State and county 27 4. Recorded production of gold and silver from counties all or partly within the Knoxville l°x2° quadrangle 28 5. Summary of high-magnesium and ultramafic rock deposits that have been mined or prospected for various mineral commodities 32 6. Olivine resources in the Knoxville l°x2° quadrangle 41 7. Palladium, platinum, and rhodium contents of various rock types from the Blue Ridge in the Knoxville l°x2° quadrangle 43 8. Deposit types, location, and geologic setting of the larger mines and metal occurrences in the Knoxville l°x2° quadrangle 57 Bedrock Geology and Mineral Resources of the Knoxville 1°x2° Quadrangle, Tennessee, North Carolina, and South Carolina By G.R. Robinson/ Jr./ F.G. Lesure, J.I. Marlow II, N.K. Foley, and S.H. Clark Abstract regional metamorphism except for a zone of retrograde rocks in the Brevard fault zone and a small area of The Knoxville 1°x2° quadrangle spans the Southern biotite-grade rocks in the extreme southwest part of the Blue Ridge physiographic province at its widest point from Grandfather Mountain window in the northeast corner of eastern Tennessee across western North Carolina to the the quadrangle. northwest corner of South Carolina. The quadrangle also The major mineral resources in the Knoxville 1°x2° contains small parts of the Valley and Ridge province in quadrangle are construction materials and a variety of Tennessee and the Piedmont province in North and South industrial minerals mostly related to either granite and Carolina. Bedrock in the Valley and Ridge consists of unmetamorphosed, folded and thrust-faulted Paleozoic pegmatite or ultramafic rocks. Past production in the miogeoclinal sedimentary rocks ranging in age from quadrangle of metals, which are of secondary importance Cambrian to Mississippian. The Blue Ridge is a complex of relative to construction materials and industrial minerals, stacked thrust sheets divided into three parts: (1) a west include copper in massive sulfides of the Besshi type, flank underlain by rocks of the Late Proterozoic and Early gold-bearing quartz veins, and residual iron and Cambrian Chilhowee Group and slightly metamorphosed manganese deposits. Resources are discussed in relation Late Proterozoic Ocoee Supergroup west of the Green­ to the Valley and Ridge, Blue Ridge, and Piedmont prov­ brier fault; (2) a central part containing crystalline inces. basement of Middle Proterozoic age (Grenville), Ocoee The following resources are the most important: Supergroup rocks east of the Greenbrier fault, and rocks A. Construction materials: of the Murphy belt; and (3) an east flank containing the 1. Dimension stone of the Tennessee marble district in Helen, Tallulah Falls, and Richard Russell thrust sheets and the Valley and Ridge. the amphibolitic basement complex. All of the east flank 2. Limestone and dolomite of the Valley and Ridge. thrust sheets contain polydeformed and metamorphosed 3. Sand and gravel and crushed stone, widespread sedimentary and igneous rocks of mostly Proterozoic age. throughout the quadrangle. The Blue Ridge is separated by the Brevard fault zone from B. Industrial minerals: a large area of rocks of the Inner Piedmont to the east, 1. Feldspar, flake mica, and quartz produced by which contains the Six Mile thrust sheet and the Chauga- flotation methods from the Spruce Pine Alaskite Walhalla thrust complex. All of these rocks are also (muscovite granodiorite) in the east flank of the Blue polydeformed and metamorphosed sedimentary and Ridge. The district produces about half of the U.S. igneous rocks. The Inner Piedmont rocks in this area feldspar and significant amounts of the U.S. flake occupy both the Piedmont and part of the Blue Ridge mica. physiographic provinces. 2. Olivine produced from alpine-type dunite bodies in The intensity of deformation and metamorphism the east flank of the Blue Ridge. increases from west to east in the Blue Ridge. The west 3. Talc and marble from the Murphy belt in the central flank is mostly chlorite grade or relatively unmetamor­ part of the Blue Ridge, phosed, and the central part of the Blue Ridge is mostly 4. Vermiculite produced from a large deposit near staurolite, garnet, or biotite grade, although sillimanite Tigerville, S.C-, in the Inner Piedmont. Deposit grade rocks occur along the eastern part of the central worked out and mine backfilled. Smaller deposits Blue Ridge in the vicinity of the leading edge of the associated with ultramafic rocks in the east flank of Hayesvil Ie fault.