Geologic map of the northern half of the Bear Creek 7.5-minute quadrangle, Chatham and Moore Counties, North Carolina

North Carolina Department of Environmental Quality Division of Energy, Mineral and Land Resources Kenneth B. Taylor, State Geologist This Geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program North Carolina Geological Survey Open File Report 2018-08 CORRELATION OF MAP UNITS 03 и о Qal V s о Ф о О. o Albemarle Arc Pluton (?) Zdi Aaron Formation Youngest detrital zircons of ca. 588 and 578 Ma (Pollock et al., 2010 and Samson et al„ 2001 , respectively) Za Zae/pl Zaqdp Hyco Formation - upper portion Metamorphosed volcaniclastic sedimentary and pyroclastic rocks associated with Hyco Formation: upper portion ca. 616 - 612 Ma (Wortman, et al., 2000; Bowman, 2010; and Bradley and Miller, 2011 ) Zhe’ Zhable .Zfidlt (u>' W ш (5‘ s *o CD_ Q> o' D (Л c D 0 & INTRODUCTION The Bear Creek 7.5-minute Quadrangle lies in the east central-portion of the North Carolina Piedmont. The unincorporated communities of Bear Creek and Harpers Crossroads are present in the quadrangle. Old US HWY 421 crosses the northeast corner, State HWY 902 diagonally cuts across the northern portion and State HWY 42 cuts across the southern portion of the quadrangle. Bear Creek controls the drainage in the northern portion of the quadrangle. Bear Creek drains to the Rocky River. The Rocky River is a major tributary of the Deep River. The southern portion of the quadrangle drains directly to the Deep River along named tributaries of Tysons Creek, Indian Creek, Little Indian Creek, Falls Creek and other unnamed tributaries. Natural exposures of crystalline and Triassic rocks primarily occur along these named and unnamed creeks. Rock exposure at road cuts, ridges, resistant finned¬ shaped outcrops and pavement outcrops locally occur outside of drainages. The elevations in the map area range from approximately 650 feet above sea level on a resistant hill, near the intersection of Siler City - Glendon Road and Providence Church Road, in the northern portion of the quadrangle, to approximately 250 feet along several tributaries draining the southern edge of the quadrangle. GEOLOGIC BACKGROUND Pre-Mesozoic crystalline rocks in the Bear Creek Quadrangle are part of the redefined Hyco Arc (Hibbard et al., 2013) within the Neoproterozoic to Cambrian Carolina terrane (Hibbard et al., 2002; and Hibbard et al., 2006). In the region of the map area, the Carolina terrane can be separated into two lithotectonic units: 1) the Hyco Arc and 2) the Aaron Formation and the associaed volcanic Virgilina member of the redefined Virgilina sequence (Hibbard et al., 2013). The Hyco Arc consists of the Hyco Formation which include ca. 633 to 612 Ma (Wortman et al., 2000; Bowman, 2010; Bradley and Miller, 2011) metamorphosed layered volcaniclastic rocks and plutonic rocks. Available age dates (Wortman et al., 2000; Bradley and Miller, 2011) indicate the Hyco Formation may tentatively be divided into lower (ca. 630 Ma) and upper (ca. 615 Ma) portions (informal) with an apparent intervening hiatus of magmatism. In northeastern Chatham County, Hyco Formation units are intruded by the ca. 579 Ma (Tadlock and Loewy, 2006) East Farrington pluton and associated West Farrington pluton. The Aaron Formation consists of metamorphosed layered volcaniclastic rocks with youngest detrital zircons of ca. 588 and 578 Ma (Pollock et al., 2010 and Samson etal., 2001, respectively). FOLDS The Hyco Arc and Aaron Formation lithologies were folded and subjected to low grade metamorphism during the ca. 578 to 554 Ma (Pollock, 2007; Pollock et al., 2010) Virgilina deformation (Glover and Sinha, 1973; Harris and Glover, 1985; Harris and Glover, 1988; and Hibbard and Samson, 1995). In the map area, original layering of Hyco and Aaron Formation lithologies are observed ranging from shallowly to steeply dipping and are interpreted to be a result of open to tight folds that are locally overturned. Four hundred and seven (407) primary bedding, layering and compaction/welding foliation measurements from this and adjacent quadrangles in the immediate area of the map were used in stereogram analyses to determine the range of fold interlimb angles. Calculated interlimb angles range from greater than 120 degrees to less than 30 degrees indicating the presence of gentle to tight folds. Preliminary domainal analyses of measurements in Hyco Formation units only, indicate the folds range from tight to open with the majority of the folds within the tight to close range. Preliminary domain analyses of measurements in Aaron Formation units only, indicate the folds range from tight to gentle with the majority of the folds within the open range. PAST WORK The map area is located within the study area of Green et al. (1982), Abdelzahir (1978), and Green (1977). Their studies documented the presence of an overlapping series of metavolcanic and metavolcaniclastic lithologies sourced from distinct areas. Nixon (1954) mapped portions of the area and investigated the historic copper prospects and mines in the area. Moore (1980) mapped and investigated felsic flows that included a small portion of the southern edge of the quadrangle. Abundant evidence of brittle faulting at the outcrop scale and large-scale lineaments (as interpreted from hillshade LiDAR data) are present in the map area. The brittle faulting and lineaments are interpreted to be associated with Mesozoic extension. The Colon cross-structure (Reinemund, 1955), located to the east of the study area, is a constriction zone in the Deep River Mesozoic basin and is characterized by crystalline rocks overprinted by complex brittle faulting. Dikes of Jurassic aged diabase intrude the crystalline rocks of the map area. Quaternary aged alluvium is present in most major drainages. MINERAL RESOURCES Glendon Pyrophyllite Deposits There is one active pyrophyllite mine in the quadrangle. Pyrophyllite is used to manufacture a variety of products for the refractory, ceramics and filler industries. The active Standard Minerals Pyrophyllite Mine is located at the southern edge of the quadrangle in Moore County. The area around the active mine is known as the Glendon pyrophyllite deposits and is home to several historic economic deposits of pyrophyllite that were first documented in the early to mid 1800's (Olmstead, 1822 and Emmons, 1856). Stuckey (1928 and 1967) and Conley (1962) conducted investigations into the structure and characteristics of the deposits. McDaniel (1976) and Spence (1975) interpreted the origin of the pyrophyllite deposits as being related to ancient hydrothermal (hot spring) activity. Klein (1985), as part of a detailed field trip guide, described aspects of the geology, mineralogy and structure of the Glendon pyrophyllite deposits. The Glendon pyrophyllite deposits consist of four mines, from southwest to northeast include; Bates (inactive), Phillips (inactive), Womble (active Standard Minerals mine) and White (inactive for pyrophyllite) Mines. The inactive Bates mine is in the quadrangle immediately to the south. Some of the early mining in the Glendon area was underground; mining is presently from open pits. The mines are located along the Glendon fault (Stuckey, 1928 and Conley, 1962). The Glendon fault is a high angle reverse fault that is a locus of pyrophyllite alteration for a distance of over 30 km (18 miles) in northeast Moore County and into southern Chatham County. The Glendon fault is interpreted to be parallel to the axial surfaces of regional-scale overturned folds and disrupts an anticline near its crest (Green et al., 1982 and Klein, 1985). In general, the fault is a zone of intense deformation ranging from 10 to 50 meters wide with abundant small-scale folds, fractures and deformed and undeformed quartz veins indicating a complicated movement history (Klein, 1985). Quartz veins may be folded and high strain foliations present within the fault zone overprint and/or transpose primary bedding and regional foliation. Northwest-trending faults of probable Mesozoic age cut the Glendon fault. Gold-pyrophyllite Belt in Moore County Lesure (1981) presented the results from a geochemical reconnaissance study from old gold mines, pyrophyllite deposits and road outcrops throughout northwestern Moore County. One hundred and ninety (190) of the rock samples contained gold in quantities ranging from 0.02 to 2.4 ppm. Twenty-six (26) samples were collected from the Glendon pyrophyllite deposits and vicinity with gold values ranged from 0.02 to 0.04 ppm. Copper Mines and Prospects Several historic copper deposits are present in southwestern Chatham County. In the Bear Creek Quadrangle, the copper deposits include several prospects and small mines including; the Barringer Phillips Prospect, the Bear Creek Mine and Phillips Mine. More detailed descriptions of the deposits are provided in Berry (1943), Nixon (1954) and Carpenter (1976). The Barringer Phillips Prospect consisted of two pits now filled in. The Bear Creek Copper Mine was worked in the 1940’s with several tons of ore removed and has an abandoned shaft up to 32 feet deep. The Phillips Mine was also worked in the 1940’s with several hundred tons of ore removed with subsequent exploration and collection of rock core; a water filled pit is all that is left of the workings. Copper minerals reported include; chalcopyrite, bornite, chalcocite, malachite and azurite. DESCRIPTION OF MAP UNITS All pre-Mesozoic rocks in the map area have been metamorphosed to at least the chlorite zone of the greenschist metamorphic facies. Many of the rocks display a weak or strong metamorphic foliation. Although subjected to metamorphism, the rocks retain relict igneous, pyroclastic, and sedimentary textures and structures that allow for the identification of protolith rocks. As such, the prefix “meta” is not included in the nomenclature of the pre-Mesozoic rocks described in the quadrangle. Jurassic diabase dikes are unmetamorphosed. Map units of metavolcanic and metavolcaniclastic rocks include various lithologies that when grouped together are interpreted to indicate general environments of deposition. The dacitic lavas and tuffs unit is interpreted to represent dacitic domes and proximal pyroclastics. The andesitic to basaltic lavas (with tuffs or conglomerates) units are interpreted to represent eruption of intermediate to mafic lava flows and associated pyroclastic and/or epiclastic deposits. The epiclastic/pyroclastic units are interpreted to represent deposition from the erosion of dormant and active volcanic highlands. Some of the metavolcaniclastic units within the map area display lithologic relationships similar to dated units present in northern Orange and Durham Counties. Due to these similarities, the metavolcanic and metavolcaniclastic units have been tentatively separated into upper and lower portions of the Hyco Formation; geochronologic data in the map area is needed to confirm this interpretation. A review of the regional lithologies is summarized in Bradley (2013). A preliminary review of the area geology is provided in Bradley (2013). Unit descriptions common to Bradley et al. (2017) and Hanna et al. (2015) from the Siler City and Siler City NE geologic maps, respectively were used for conformity with on strike units in neighboring quadrangles. Unit descriptions and stratigraphic correlations were maintained from adjacent mapping in Orange County (Bradley et al., 2016). The nomenclature of the International Union of Geological Sciences subcommission on igneous and volcanic rocks (IUGS) after Le Maitre (2002) is used in classification and naming of the units. The classification and naming of the rocks is based on relict igneous textures, modal mineral assemblages, or normalized mineral assemblages when whole-rock geochemical data is available. Pyroclastic rock terminology follows that of Fisher and Schminke (1984). Sedimentary Unit Qal / A ■Jd Zdi Zae/pl Zaqdp Za Zhe* Zhime/pl 'Zhdlt (d) . Zhable Qal - Alluvium: Unconsolidated poorly sorted and stratified deposits of angular to subrounded clay, silt, sand and gravel- to boulder-sized clasts, in stream drainages. May include point bars, terraces and natural levees along larger stream floodplains. Structural measurements depicted on the map within Qal represent outcrops of crystalline rock inliers surrounded by alluvium. Intrusive and Metaintrusive Units Jd - Diabase: Black to greenish-black, fine- to medium-grained, dense, consists primarily of plagioclase, augite and may contain olivine. Locally has gabbroic texture. Occurs as dikes up to 100 ft wide. Diabase typically occurs as spheriodally weathered boulders with a grayish-brown weathering rind. Red station location indicates outcrop or boulders of diabase. Purple stations indicate outcrops or boulders of gabbroic textured diabase. Zdi - Diorite: Mesocratic (CI-50), greenish-gray to grayish-green, fine- to medium-grained, metamorphosed, hypidiomorphic granular diorite. Major minerals include plagioclase and amphibole. Plagioclase crystals are typically sericitized and saussuritized. Amphiboles are typically altered to chlorite and actinolite masses. Gabbro intermingled locally. Metavolcanic and Metavolcaniclastic Units Aaron Formation Zae/pl - Aaron Formation (Virgilina member) mixed epiclastics, pyroclastics and lavas of the Devils Tramping Ground area: Grayish-green to greenish- gray, metamorphosed tuffaceous sandstones, conglomeratic sandstones, siltstones and minor phyllite. The siltstones typically are weakly phyllitic. Contains lesser amounts of fine- to coarse tuff, welded tuff and dacitic lavas. Fiamme-like shaped clasts are common in the conglomerates sandstones and tuffs. Quartz and feldspar crystal fragments are common in the sedimentary components, tuffs and lavas. Silicified and/or sericitized altered rock and quartz with adularia and locally present. Unit is interpreted to be in gradational contact with unit Za. Contact with unit Za designated at first occurrence of sandstones with angular clasts or primary volcanic rocks. Zaqdp - Quartz dacite porphyry: Porphyritic with aphanitic groundmass and sub- to euhedral phenocrysts (2-6 mm) of white to salmon plagioclase and gray to dark gray (beta-) quartz; phenocrysts typically constitute 20 to 25% of the rock. May locally have fine-grained intrusive texture. Interpreted as either lava flows or shallow intrusives possibly associated with domes. Similar to quartz dacite porphyry unit within the Bynum Quadrangle (Bradley et al., 2013). Za - Aaron Formation: Distinctive metasedimentary package that ranges from fine-grained siltstones to coarse-grained sandstones, pebbly sandstones and conglomerates. Siltstones are similar in appearance to Hyco Formation lithologies. The sandstones, pebbly sandstones and conglomerates (classified as litharenite, feldspathic litharenite and lithic feldsarenite by Harris (1984)) are distinctive and commonly contain rounded to subrounded clasts of quartz ranging from sand- to gravel-sized. In the sandstones, feldspar is the most prominent mineral grain; quartz varies from sparse to abundant in hand sample. Lithic clasts are typically prominent and range from sand- to gravel-size. Harris (1984), performed a detailed sedimentary study of the Aaron Formation to the immediate west of the map area. Harris (1984) interpreted the Aaron Formation to have been deposited by turbidity currents in a retrogradational submarine fan setting. Pollock et al., (2010) interprets an approximate 35 million year unconformity between the Aaron and underlying Hyco Formation. This interpretation is based in part on detrital zircon age date data from an Aaron conglomerate sample collected in the nearby Liberty Quadrangle. Hyco Formation - Upper Portion Zhe* - Epiclastic rocks of the Southern Chatham County area: Grayish-green to green, locally with distinctive reddish-gray or maroon to lavender coloration, siltstones, sandstones, conglomeratic sandstone, and conglomeratic siltstone (greywacke). Siltstones are locally phyllitic. Siltstones typically display bedding ranging from mm-scale up to 10 cm, bedding layers traceable for several feet locally, may exhibit soft sediment deformation. Locally tuffaceous with a relict vitric texture. Locally contain interbedded intermediate to mafic lavas. Conglomerates and conglomeratic sandstones typically contain rounded to angular clasts. Deposition interpreted as distal from volcanic center. Zhime/pl - Mixed intermediate to mafic epi clastic-pyroclastic rocks with interlayered intermediate to mafic lavas: Grayish-green to green, locally with distinctive reddish-gray or maroon to lavender coloration; metamorphosed: conglomerate, conglomeratic sandstone, sandstone, siltstone and mudstone. Lithologies are locally bedded; locally tuffaceous with a cryptocrystalline-like groundmass. Siltstones are locally phyllitic. Locally contain interbedded intermediate to mafic lavas identical to the Zhable unit. Contains lesser amounts of fine- to coarse tuff and lapilli tuff with a cryptocrystalline-like groundmass. Pyroclastics, lavas, and epiclastics are mainly intermediate to mafic in composition. Minor dacitic lavas and tuffs present. Silicified and/or sericitized altered rock are locally present. Conglomerates and conglomeratic sandstones typically contain subrounded to angular clasts of andesite and basalt in a clastic matrix. Generally interpreted to have been deposited proximal to active intermediate to mafic composition volcanic centers and/or record the erosion of proximal intermediate to mafic composition volcanic centers after cessation of active volcanism. Zhdlt (u) - Dacitic lavas and tuffs of the upper portion of the Hyco Formation: Greenish-gray to dark gray, siliceous, metamorphosed; aphanitic dacite, porphyritic dacite with plagioclase phenocrysts, and flow banded dacite. Dacite with hyaloclastic textures are common. Welded and non-welded tuffs associated with the lavas include: greenish-gray to grayish-green, fine tuff, coarse plagioclase crystal tuff and lapilli tuff. Locally, interlayers of immature conglomerate and conglomeratic sandstone with abundant dacite clasts are present. The dacites are interpreted to have been coherent extrusives or very shallow intrusions associated with dome formation. The tuffs are interpreted as episodic pyroclastic flow deposits, air fall tuffs or reworked tuffs generated during formation of dacite domes. Wortman et al. (2000) reports an age of 615.7+3.7/-1.9 Ma U-Pb zircon date for a dacitic tuff from the unit in the Rougemont quadrangle. Zhable - Andesitic to basaltic lavas with interlayered epiclastic rocks: Light green, gray-green, gray, and dark gray; typically unfoliated, amygdaloidal, plagioclase porphyritic, amphibole/pyroxene porphyritic and aphanitic; metamorphosed: andesitic to basaltic lavas and shallow intrusions. Hyaloclastic texture is common and imparts a fragmental texture on some outcrops and float boulders. Contains lesser amounts of grayish-green, light green, and light gray to white; metamorphosed conglomerate, conglomeratic sandstone, sandstone, siltstone and mudstone. 79 22' 30" 35 37' 30" EXPLANATION OF MAP SYMBOLS CONTACTS, FAULTS, AND OTHER FEATURES inferred contact concealed contact gradational contact - inferred inferred brittle fault; dotted where concealed D indicates downthrown side, U indicates upthrown side quaternary alluvium contact linear geomorphic feature interpreted from hillshade LiDAR - origin uncertain -4- — f— interpreted fold hinge of anticline; dotted where concealed interpreted fold hinge of syncline; dotted where concealed — ^ - interpreted fold hinge of overturned anticline - ^ - interpreted fold hinge of overturned syncline inferred diabase dike; dotted where concealed cross section IN CROSS SECTIONS Hill lllll Hill Hill inferred contact inferred gradational contact brittle fault inferred fold axis in H h 74 strike and dip of primary bedding and/or layering strike and dip of primary bedding and/or layering PLANAR AND LINEAR FEATURES r”L e* i strike and dip of inclined regional foliation 84 (multiple observations at one location) ^ strike of vertical joint surface ro (multiple observations at one location) ( strike and dip of primary volcanic compaction and/or welding foliation 3 strike and dip of inclined regional foliation 77 strike and dip of cleavage П m strike and dip of cleavage 84 (multiple observations atone location) |i 71 strike and dip of inclined joint surface 78 i strike and dip of inclined joint surface 82 (multiple observations at one location) strike of vertical joint surface (multiple observations at one location) clast lineation PROSPECTS AND QUARRIES X и prospect (pit or small open cut) 1 Roads Prospect - copper (USGS, MRDS); Not confirmed by NCGS 4 prospect - unknown commodity (identified by Nixon, 1954); Not confirmed by NCGS 5 Barringer Phillips Prospect- copper (USGS, MRDS; Carpenter, 1976) 6 Oldham Pyrophyllite Pit - pyrophyllite (Reinemund, 1955); approximate location 7 Jones Pyrophyllite Pit - pyrophyllite (Reinemund, 1955); approximate location 8 Currie Pyrophyllite Pit - pyrophyllite (Reinemund, 1955); approximate location mine shaft - abandoned 2 Bear Creek Mine -copper (USGS, MRDS; Carpenter, 1976; Nixon, 1954) quarry or mine - active 10 Standard Minerals (Womble) Pyrophyllite Mine - pyrophyllite ^ quarry or mine - abandoned 3 Phillips Mine -copper (USGS, MRDS; Carpenter, 1976; Nixon, 1954) 9 White (Snow) Pyrophyllite Mine - pyrophyllite (Reinemund, 1 955) 11 Phillips Pyrophyllite Mine - pyrophyllite 0 Geochemical sample location 12 Nd isotope analysis HOC92-7 (Samson et al., 1995) 13 Nd isotope analysis HOC92-8 (Samson et al., 1995) © OTHER FEATURES observation station location • diabase station location indicates location of quartz dacite porphyry boulders or outcrop indicates location of gabbroic diabase boulders or outcrop Л indicates location of vuggy and/or massive quartz float REFERENCES; Abdelzahir, A.M., 1978, The geology of the Carolina slate belt, northern Moore County, North Carolina, unpublished M.S. thesis, North Carolina State University, Raleigh, North Carolina, 67 p. Allmendinger, R. W., Cardozo, N. С., and Fisher, D., 2013, Structural Geology Algorithms: Vectors and Tensors: Cambridge, England, Cambridge University Press, 289 pp. Berry, E.W., 1943, The copper prospects of Chatham County: North Carolina Department of Conservation and Development, Division of Mineral Resources, Report of Investigation - The Copper Prospects of Chatham County, R.l. 43, 8p. Bowman, J.D., 2010, The Aaron Formation; Evidence for a New Lithotectonic Unit in Carolinia, North Central North Carolina, unpublished M.S. thesis, North Carolina State University, Raleigh, North Carolina, 116 p. Bradley, P.J., and Miller, B.V., 2011, New geologic mapping and age constraints in the Hyco Arc of the Carolina terrane in Orange County, North Carolina: Geological Society of America Abstracts with Programs, Vol. 43, No. 2. Bradley, P.J., 2013, The Carolina terrane on the west flank of the Deep River Basin in the northern Piedmont of North Carolina - A Status Report, in Hibbard, J.P. and Pollock, J.C. editors, 2013, One arc, two arcs, old arc, new arc: The Carolina terrane in central North Carolina, Carolina Geological Society field trip guidebook, pp. 139-151. Bradley, P.J., Hanna, H.D., Gay, N.K., Stoddard, E.F., Bechtel, R., Phillips, C.M., and Fuemmeler, S. J, 2016, Geologic map of Orange County, North Carolina: North Carolina Geological Survey Open-file Report 2016-05, scale 1:50,000, in color. Bradley, P.J., Peach, B.T. and Hanna, H.D 2017, Geologic map of the Siler City 7.5-Minute Quadrangle, Chatham County, North Carolina; North Carolina Geological Survey Open-file Report 2017-07, scale 1 :24,000, in color (Supersedes Open-file Report 2016-08). Cardozo, N., and Allmendinger, R. W., 2013, Spherical projections with OSXStereonet: Computers and Geosciences, v. 51, no. 0, p. 193 - 205, doi: 10. 101 6j/.cageo. 201 2.07.021 Carpenter, P. Albert III., 1976 (reprinted 1993), Metallic mineral deposits of the Carolina Slate, North Carolina Geological Survey, Bulletin 84, 89p. Conley, J.F., 1962, Geology and mineral resources of Moore County, North Carolina: Division of Mineral Resources, North Carolina Department of Conservation and Development, Bulletin 76, 40 p. Emmons, E., 1856, Geological Report of the Midland Counties of North Carolina: North Carolina Geological Survey, Miscellaneous Publication. Fisher, R.V., and Schmincke H.-U., 1984, Pyroclastic rocks, Berlin, West Germany, Springer-Verlag, 472 p. Glover, L., and Sinha, A., 1973, The Virgilina deformation, a late Precambrian to Early Cambrian (?) orogenic event in the central Piedmont of Virginia and North Carolina, American Journal of Science, Cooper v. 273-A, pp. 234-251 . Green, G., 1977, The geology of the slate belt rocks of the Goldston and Bear Creek quadrangles, North Carolina, un-published M.S. thesis, North Carolina State University, Raleigh, North Carolina, 68 p. Green, G., Cavaroc, V., Stoddard, E., Abdelzahir, A., 1982, Volcanic and volcaniclastic facies in a part of the slate belt of North Carolina, In: Bearce, D., Black, W., Kish, S., Tull, J. (Eds.), Tectonic studies in the Talladega and Carolina slate belts, Southern Appalachian Orogen. Geological Society of America Special Paper, vol. 191, pp.109- 124. Hanna, H.D., Bradley, P.J., and Bechtel, R., 2015, Geologic Map of the Siler City NE 7.5 Minute Quadrangle, Chatham County, North Carolina: North Carolina Geological Survey Open-file Report 201 5-02, scale 1:24,000, in color. Harris, C.W., 1984, Coarse-grained submarine-fan deposits of magmatic arc affinity in the late Precambrian Aaron Formation, North Carolina, U.S.A., Precambrian Research, 26, pp. 285-306. Harris, C., and Glover, L., 1985, The Virgilina deformation: implications of stratigraphic correlation in the Carolina slate belt, Carolina Geological Society field trip guidebook, 36 p. Harris, C., and Glover, 1988, The regional extent of the ca. 600 Ma Virgilina deformation: implications of stratigraphic correlation in the Carolina terrane, Geological Society of America Bulletin, v. 100, pp. 200-217. Hibbard, J., and Samson, S., 1995, Orogenesis exotic to the lapetan cycle in the southern Appalachians, In, Hibbard, J., van Staal, C., Cawood, P. editors, Current Perspectives in the Appalachian- Caledonian Orogen. Geological Association of Canada Special Paper, v. 41, pp. 191-205. Hibbard, J., Stoddard, E.F., Secor, D., Jr., and Dennis, A., 2002, The Carolina Zone: Overview of Neoproterozoic to early Paleozoic peri-Gondwanan terranes along the eastern flank of the southern Appalachians: Earth Science Reviews, v. 57, n. 3/4, p. 299-339. Hibbard, J. P., van Staal, C. R., Rankin, D. W., and Williams, H., 2006, Lithotectonic map of the Appalachian Orogen, Canada-United States of America, Geological Survey of Canada, Map- 2096 A. 1:1, 500, 000-scale. Hibbard, J.P., Pollock, J.C., and Bradley, P.J., 2013, One arc, two arcs, old arc, new arc: An overview of the Carolina terrane in central North Carolina, Carolina Geological Society field trip guidebook, 265 p. Klein, T.L., 1985, Glendon Pyrophyllite deposits - Stops 2-10, in Feiss, P.G., editor, Volcanic-hosted gold and high-alumina rocks of the Carolina slate belt, guidebook for the field trip held in conjunction with the 1985 fall meeting of the Society of Economic Geologists and the 1985 annual meeting of the Geological Society of America, Orlando, Florida, p. 48-72. Le Maitre, R.W., Ed., 2002, Igneous Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences (IUGS) Subcommission on the Systematics of Igneous Rocks: Cambridge, Cambridge University Press, 252 p. Lesure, F.G., 1981, Map showing reconnaissance geochemistry in the gold-pyrophyllite belt of northwestern Moore County, North Carolina: U.S. Geological Survey, Miscellaneous Field Studies Map MF-1301, scale 1:48000. McDaniel, R.D., 1976, Application of hot spring-fumerole alteration model to the genesis of the pyrophyllite deposits of the Carolina slate belt, unpublished M.S. thesis, North Carolina State University, Department of Geosciences, Raleigh, North Carolina, 75 p. Moore, B.R., 1980, Investigations of a felsic flow, northern Moore County, North Carolina, unpublished M.S. thesis, North Carolina State University, Raleigh, North Carolina 70 p. Nixon, E.C., 1954, Geology of the Harpers Crossroads area, southwestern Chatham County, North Carolina: Unpublished Master’s Thesis, North Carolina State College, Raleigh, 39 p. Olmstead, D., 1822, On the gold mines of North Carolina, American Journal of Science, v.9, p.5-15. Pollock, J. C., 2007, The Neoproterozoic-Early Paleozoic tectonic evolution of the peri-Gondwanan margin of the Appalachian orogen: an integrated geochronological, geochemical and isotopic study from North Carolina and Newfoundland. Unpublished PhD dissertation, North Carolina State University, 194 p. Pollock, J.C., Hibbard, J.P., and Sylvester, P.J., 2010, Depositional and tectonic setting of the Neoproterozoic-early Paleozoic rocks of the Virgilina sequence and Albemarle Group, North Carolina: in Tollo, R.P., Bartholomew, M.J., Hibbard, J.P., and Karabinos, P.M., eds., From Rodinia to Pangea: The Lithotectonic Record of the Appalachian Region: Geological Society of America Memoir 206, p. 739-772. Reinemund, J.A., 1955, Geology of the Deep River coal field, North Carolina: U.S. Geol. Survey Prof. Paper 246, 159 p. Samson, S., Hibbard, J., and Wortman, G., 1995, Nd isotopic evidence for juvenile crust in the Carolina terrane, southern Appalachians: Contributions to Mineralogy and Petrology, v. 121 , p. 171-184. Samson, S.D., Secor, D.T, and Hamilton, M.A., 2001, Wandering Carolina: Tracking exotic terranes with detrital Zircons, GSA Abstracts with Programs Vol. 33, No. 6, p. A-263. Spence, W.H., 1975, A model for the origin of the pyrophyllite deposits in the Carolina slate belt (abstract.). Geological Society of America Abstracts with Programs, v. 7, 536 p. Stuckey, J.L., 1928, Pyrophyllite deposits of North Carolina: North Carolina Department of Conservation and Development, Bulletin 37, 62 p. Stuckey, J.L., 1967, Pyrophyllite Deposits in North Carolina: North Carolina Geological Survey, Bulletin 80, scale 1:500000. Tadlock, K.A., and Loewy, S.L., 2006, Isotopic characterization of the Farrington pluton: constraining the Virgilina orogeny, in Bradley, P.J., and Clark, T.W., editors, The Geology of the Chapel Hill, Hillsborough and Efland 7.5-minute Quadrangles, Orange and Durham Counties, Carolina Terrane, North Carolina, Carolina Geological Society Field Trip Guidebook for the 2006 annual meeting, pp. 17-21. Wortman, G.L., Samson, S.D., and Hibbard, J.P., 2000, Precise U-Pb zircon constraints on the earliest magmatic history of the Carolina terrane, Journal of Geology, v. 108, pp. 321-338. Equal-Area Schmidt Net Projections and Rose Diagram Plots and calculations created using Stereonet v. 8.6.0 based on Allmendinger et al. (201 3) and Cardozo and Allmendinger (201 3). 79 30' Topographic base produced by the United States Geological Survey. Altered by the North Carolina Geological Survey for use with map. North American Datum of 1983 (NAD83) World Geodetic System of 1984 (WGS84). Projection and 1 000-meter grid: Universal Transverse Mercator, Zone 17S 10 000-foot ticks: North Carolina Coordinate System of 1983 This map Is not a legal document. Boundaries may be generalized for this map scale. Private lands within government reservations may not be shown. Obtain permission before entering private lands. Imagery . NAIP, August 2014 Roads . U.S. Census Bureau, 2015 - 2016 Names . GNIS, 2016 Hydrography . National Hydrography Dataset, 2014 Contours . National Elevation Dataset, 2008 Boundaries . Multiple sources; see metadata file 1972 - 2016 Wetlands . FWS National Wetlands Inventory 1977 - 2014 35 30' 79 22' 30" 30" тЬшаД c 0.5 SCALE 1:24 000 KILOMETERS ROAD CLASSIFICATION 1000 500 0‘ 54 16MILS 0.5 METERS 0 1000 2000 Expressway Secondary Hwy Ramp Local Connector Local Road 4WD 1000 1000 2000 3000 MILES 4000 5000 6000 7000 I Interstate Route 8000 9000 10000 QUADRANGLE LOCATION О Route О State Route UTM GRID AND 2016 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET U.S. National Grid 100,000 m Square ID PV Grid Zone Destination 17 S FEET CONTOUR INTERVAL 10 FEET NORTH AMERICAN VERTICAL DATUM OF 1988 This map was produced to conform with the National Geospatial Program USTopo Product Standard, 2011. A metadata file associated with this product is draft version 0.6,19 1 2 3 4 5 6 7 8 1 Coleridge 2 Siler City 3 Siler City NE 4 Bennett 5 Goldston 6 Robbins 7 Putnam 8 White Hill BEAR CREEK, NC AP JOINING QUADRANGLES Equal Area Schmidt Net Projection of Contoured Poles to Primary Bedding and Layering Contour Interval =3 sigma; N=68 Bear Bear Bill Lambert Siler City Glendon NC HWY Zeb Brooks Equal Area Schmidt Net Projection of Contoured Poles to Foliation and Cleavage Contour Interval =4 sigma; N=190 TRAVERSE MAP Hillshade derived from a 20 foot LiDAR digital elevation model. Red and blue lines show paths of field traverses. Unidirectional Rose Diagram of Joints N = 215 Outer Circle = 10% Mean vector = 341 .2° ± 08.3°; Max value =15.81395% between 151° and 160° Environmental Quality This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program under StateMap award number G17AC00264, 2017. This map and explanatory information is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints for governmental use. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. Geologic Map of the Northern Half of the Bear Creek 7.5-Minute Quadrangle, Chatham and Moore Counties, North Carolina. By Brandon T. Peach and Philip J. Bradley Geologic data collected in June 2017 through May 2018. Map preparation, digital cartography and editing by Michael A. Medina, Brandon T. Peach and Philip J. Bradley. 2018 by car by foot This is an Open File Map. It has been reviewed internally for conformity with North Carolina Geological Survey mapping standards and with the North American Stratigraphic Code. Further revisions or corrections to this Open File map may occur. Geologic Map of the Northern Half of the Bear Creek 7.5-Minute Quadrangle, Chatham and Moore Counties, North Carolina. Open File Report 2018-08