Geologic maps and block diagrams of the Barite Hill gold-silver deposit and vicinity, South Carolina and Georgia

Clark, Sandra H. B. · 1999 · Report

Geologic Maps and Block Diagrams of the Barite Hill Gold- Silver Deposit and Vicinity, South Carolina and Georgia By Sandra H.B. Clark, U.S.

This 1999 document, Geologic maps and block diagrams of the Barite Hill gold-silver deposit and vicinity, South Carolina and Georgia, is preserved in the Mountain Man Mining Library for research and reference. Original source: pubs.usgs.gov.

U. S. DEPARTMENT OF THE INTERIOR Geologic Maps and Block Diagrams of the Barite Hill Gold- Silver Deposit and Vicinity, South Carolina and Georgia By SandraH.B. Clark U.S. Geological Survey, National Center, MS 954, Reston, VA 22092 This report is preliminary and has not been reviewed for conformity with U.S.Geological Survey editorial standards or with the North American Stratigraphic code. Any use of trade, product or firm names is for descriptive purposed only and does not imply endorsement by the U.S. Government. U.S. Geological Survey Open-File Report 99-1486

Geologic Maps and Block Diagrams of the Barite Hill Gold- Silver Deposit and Vicinity, South Carolina and Georgia By Sandra H.B. Clark, U.S. Geological Survey, National Center, MS 954, Reston, VA 22092 Barite Hill is a metavolcanic-rock-hosted, stratiform gold-silver deposit located in the Piedmont physiographic province in McCormick County, South Carolina. The deposit is in the Lincolnton-McCormick district, which includes other mines and prospects for gold, silver, copper, zinc, lead, kyanite, and manganese, in rocks of the southern Carolina slate belt (pi. 1). The Barite Hill deposit was mined from 1990 to 1994, and, during this time, approximately 1,835,000 grams of gold and 3,390,280 grams of silver were produced S, Wilkerson and D.W. Halverson, Nevada Goldfields, oral commun., 1994), mainly from oxidized ores in the Main and Rainsford Pits (pl.2) The purpose of this report is to make available a regional geologic map (pi. 1), and geologic maps (pi. 2) and block diagrams (pi. 3) of the Barite Hill mine to supplement a brief summary of the geology of the deposit (Clark, 1997) and a more detailed report by Clark, Gray, and Back (in press). The maps in this report supersede geologic maps that appear in preliminary reports on geochemical profiles (Clark and others, 1993) and results of petrographic studies (Back and Clark, 1993). Host rocks for the Barite Hill deposit are sericitically-altered, felsic metavolcanic and metasedimentary rocks of the Late Proterozoic Persimmon Fork Formation, which consists of the Lincolnton metaryholite and the overlying lower and upper pyroclastic units. The Barite Hill deposit lies stratigraphically below an overturned contact between the upper and lower pyroclastic units. The Main Pit contains four parallel zones of gold-silver mineralization: footwall, middle, hanging wall, and Red Hill ore zones. The Rainsford Pit contains only one gold-silver-rich zone, which is the stratigraphic equivalent of the footwall ore zone in the Main Pit. Gold-silver-rich zones in the Main Pit are partly coincident with lenses of siliceous barite rock, but not confined to them, and occur more commonly in pyrite-quartz altered fragmental rock. The stratigraphically uppermost of the four ore zones in the Main Pit is overlain by a zone of barite and base-metal enrichment, which is, in turn, overlain by a talc-tremolite alteration zone. Siliceous barite zones are absent in the Rainsford Pit, and gold-silver minerals are associated with silicified rocks and chert. The Barite Hill deposit is interpreted to be the result of Kuroko-type submarine volcanogenic base-metal sulfide mineralization followed by precious metal deposition under epithermal conditions. The stages of evolution of the Barite Hill deposit as related to the regional volcanic, tectonic, and thermal history are summarized in Table 1.

Table 1. Summary of stages of evolution of the Barite Hill gold deposit. Sequence of Events Recorded at Barite Hill Results Probable Correlation with Regional Events Submarine volcanism; hydrothermal fluids moved through, altered, and mineralized the volcanic pile, and were exhaled onto the seafloor. Deposition massive sulfide, barite, and fine-grained silicic exhalites in pyroclasitc sequence. Alteration of volcanic host rocks and sediments near the seawater interface. Late Proterozoic to Cambrian volcanism and sedimentation related to plate convergence and subduction, possibly in a microcontinental or islandarc setting distant from trn ancestral North American continental plate Waning stages of hydrothermal activity in a failed massive sulfide system or a separate epithermal event. Au-Ag-Te and base-and precious-metal tellurideselenide-bismuth mineralization. Late stages of the volcanic phase or a later event. Greenschist facies metamorphism, folding and thrust faulting. Development of pervasive cleavage parallel to axial planes of tight to isoclinal folds, shearing of folds, development of greenschistfacies mineral assemblage, recrystallization of siliceousbarite and massive sulfide minerals in lenses that are elongate parallel to regional cleavage Middle to Late Ordovician Taconic collision of the Carolina terrane with the North American continent. Late-to post-tectonic remobilization of quartz, barite, and gold. Cross-cutting quartz and barite veins. Late phases of Taconic orogeny, Middle Paleozcfc thermal events, and (or) the Alleghanian orogeny High-angle faulting. Offset of orebodies Mesozoic rifting. Deep weathering and oxidation. Removal of base-metal sulfides and precipitation of ferric oxide-hydroxide gossans and barite crystals in upper part of mineralized zone. Quaternary exposure to ground water and atmospheric conditions.

REFERENCES CITED Back, J. M., and Clark, S.H.B., 1993 (for 1992) Preliminary results of petrographic studies of the Barite Hill gold deposit in the southern Carolina slate belt, South Carolina: South Carolina Geology, v. 35, p. 67-78. Biggs, T.H., 1982, The geology of the McCormick area, McCormick County, South Carolina: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 221 p. Clark, S.H.B., 1997, Barite Hill--An example of gold-silver mineralization associated with barite and base metal sulfides in Late Proterozoic felsic volcanic rocks in the Carolina slate belt of South Carolina and Georgia, U.S.A.: Proceedings of the 30th International Geological Congress, v. 9, p 441-452. Clark, S.H.B., Bryan, N.L., Greig, D.D., Padgett, J.P., and Watkins, D.R., 1993 (for 1992), Geochemical profiles of six reverse-circulation drill holes from the Barite Hill gold deposit, South Carolina: South Carolina Geology, v. 35, p. 55-63. Clark, S.H.B., Gray, K.J., and Back, J.M., in press, Geology of the Barite Hill gold-silver deposit in the southern Carolina slate belt: Economic Geology, 42 ms pages. Delia, R.G., 1982, The geology of the southern half of the Wellington 7 1/2-minute quadrangle, South Carolina-Georgia: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 202 p. Fay, W.M., 1980, Geologic and geochemical studies of the Lincolnton and Plum Branch quadrangles, Georgia and South Carolina: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 145 p. Goldstein, S.B., 1980, Geology of the Civil War mine area: Lincoln County, Georgia: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 170 p. Guthrie, V.N., 1980, Geology of the Dorn mine, McCormick, South Carolina: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 165 p. Maher, H. D., Jr., and Sacks, P. E., compilers, 1987, Geologic map of the Clarks Hill and Lean quadrangles, SC and GA, in Secor, D.T., Anatomy of the Alleghanian orogeny as seen from the Piedmont of South Carolina: Carolina Geological Society Field Trip Guidebook, Nov. 14-15, 1987, pi. 1, scale, 1:24,000. Padgett. J., and Watkins, D., 1988, Report on the Barite Hill project, McCormick County, South Carolina: BP Minerals America, unpub. report, 35 p. Paris, T.A., 1976, Geology of the Lincolnton 7 1/2 ' quadrangle, Georgia-South Carolina: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 191 p. Reusing, S.P., 1979, Geology of the Graves Mountain area, Lincoln and Wilkes Counties, Georgia: Athens, Georgia, University of Georgia, unpub. M.S. thesis, 121 p. Sibley, M.J., 1982, Geology of the Magruder-Chambers prospect area, Lincoln and Wilkes Counties, Georgia: Athens, Georgia, University of Georgia M.S. thesis, 190 p.