GEOLOGY OF SELECTED MAFIC AND ULTRAMAFIC ROCKS OF GEORGIA: A REVIEW Compiled by Harold R. Vincent Keith I. McConnell Philip C. Perley DEPARTMENT OF NATURAL RESOURCES ENVIRONMENTAL PROTECTION DMSION INFORMATION CIRCULAR 82 GEORGIA GEOLOGIC SURVEY Cover photo: Typical outcrop of metagabbroic rocks of the Brasstown complex, exposed along the shore of Lake Chatuge, near the old Lower Bell Creek corundum mine, approximately 1-3/4 miles north of Hiawassee, Towns County, Georgia. GEOLOGY OF SELECTED MAFIC AND ULTRAMAFIC ROCKS OF GEORGIA: A REVIEW Compiled by Harold R. Vincent Keith I. McConnell Philip C. Perley Georgia Department of Natural Resources J. Leonard Ledbetter, Commissioner Environmental Protection Division Harold F. Reheis, Assistant Director Georgia Geologic Survey William H. McLemore, State Geologist Atlanta 1990 INFORMATION CIRCULAR 82 TABLE OF CONTENTS Page Introduction ................................................................................................................. 1 Methods of Investigation ............................................................................................. _, ....... 1 An Overview of Previous Investigations .................................................................................... .1 Blue Ridge ................................................................................................................ 1 Northern Piedmont/Blue Ridge? .......................................................................................... .3 Southern Piedmont ... : . ................................................................................................. 4 Blue Ridge Mafic and Ultramafic Rocks .................................................................................... .4 Introduction ..............................................................................................................4 Marble Hill Metagabbro .................................................................................................. 5 Chatsworth Talc District .................................................................................................. 5 Northern Piedmont Mafic and Ultramafic Rocks ........................................................................... .7 Introduction .............................................................................................................. 7 Lake Chatuge Complex ...................................................................................................7 Dicks Creek Suite ................................................................................................. ·........ 9 Lake Burton Dunite ..................................................................................................... 11 Beavert Mountain Suite .................................................................................................. 13 Laurel Creek Mafic-Ultramafic Complex ................................................................................ 15 Laura Lake Mafic Complex .............................................................................................. 15 Kellogg Creek Mafic Complex ........................................................................................... 19 Holly Springs Ultramafite ................................................................................................ 20 Carrollton Suite . 22 Southern Piedmont Mafic and Ultramafic Rocks ........................................................................... 22 Introduction . 22 Soapstone Ridge Complex .............................................................................................. 22 Whitewater Creek Metagabbro ......................................................................................... 25 Morning Creek Metapyroxenite ......................................................................................... 25 Durham Town Metagabbro ............................................................................................ .28 Burks Mountain Suite .................................................................................................. 30 Coody Creek Suite .......................................................................................................32 Berner Mafic Complex .................................................................................................. 35 Gladesville Gabbro . 35 Juliette Mafic Suite ................................................................................................... 37 Monticello- Metagabbro ...............................................................................................37 Griggs Chapel Metagabbro .............................................................................................. 37 Metagabbro Exposed near Cedar Creek .........................................................., ....................... 37 Metagabbro Exposed at the Little River, Putnam County .............................................................. 39 Ultramafic Rock Exposed Southwest of Musella Community ......................................................... 39 Chlorite-Actiniolite Schist Near Shoulderbone Creek ................................................................... 44 Diabase ............................................................ _....................................................... 44 Additional Occurrences . 44 Lincoln County ......................................................................................................... 44 Oglethorpe County ..................................................................................................... 44 Haralson County ....................................................................................................... 44 Jasper County .......................................................................................· ................... 46 Lumpkin County ..................................................................................................... 46 Troup County .......................................................................................................... 46 Putnam County ......................................................................................................... 46 Presley's Mill Gabbro ................................................................................................ 46 Rudden Metapyroxenite............................................................................................... 49 Other Bodies ......................................................................................................... 49 Summary ........................................................................................... _....................... 49 References Cited ........................................................................................................... 49 Appendices ................................................................................................................. 53 iii LIST OF FIGURES Page Figure 1. Generalized location map of mafic and ultramafic rock bodies described in this report. ................... 2 Figure 2. Location map of the Marble Hill Metagabbro, Pickens County. .......................................... 6 Figure 3. Location map of the Chatsworth Talc District· · · · · · · · · · · · · · · · · · · · · · ........................................ 8 Figure 4. Generalized geologic map of the Lake Chatuge complex, Towns and Union Counties ..................... .10 Figure 5. Location map of Dicks Creek suite and Lake Burton dunite, Rabun County............................... 12 Figure 6. Location map of the Beavert Mountain suite, Rabun County ................. ·............................. 14 Figure 7. Location map of the Laurel Creek mafic-ultramafic complex .............................................. 16 Figure 8. Generalized geologic map of the Laurel Creek Mine area .................................................. .17 Figure 9. Location map of the Laura Lake Mafic Complex, Cobb and Cherokee Counties; and the Kellogg Creek Mafic Complex, Bartow, Cherokee, Cobb and Paulding Counties ....................................... 18 Figure 10. Location map of the Holly Springs ultramafite, Cherokee County......................................... 21 Figure 11. Location map of ultramafic rock near Carrollton, Carroll County. ...................................... 23 Figure 12. Location map of the Soapstone Ridge Complex, Clayton, DeKalb and Fulton Counties ............ 24 Figure 13. Location map of the Whitewater Creek metagabbro, Heard County....................................... 26 Figure 14. Location map of the Morning Creek metapyroxenite, Fayette County ..................................... 27 Figure 15. Location map of the Durham Town metagabbro, Greene County......................................... 29 Figure 16. Location map of the Burks Mountain suite, Columbia County............................................. 31 Figure 17. Location map of the Coody Creek suite, Elbert County .................................................... 33 Figure 18. Location map of the Gladesville gabbro and a metagabbro exposed north of McElheney's Crossroads, Jasper County .............................................................................................. 36 Figure 19. Location map of the Juliette mafic suite, Monroe County.................................................. 38 Figure 20. Location map of metagabbro near Griggs Chapel, Jasper County.........................................