Bedrock geologic map of the Essex 7.5-minute quadrangle, Nash, Halifax and Warren Counties, North Carolina

DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF ENERGY, MINERAL, AND LAND RESOURCES TRACY E. DAVIS, DIRECTOR NORTH CAROLINA GEOLOGICAL SURVEY KENNETH B. TAYLOR, STATE GEOLOGIST This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program OPEN FILE REPORT 2015-01 Equal Area Schmidt Net Projection of Contoured Poles to Primary Bedding and Compositional Layering Contour Interval = 2 sigma N=155 Equal Area Schmidt Net Projection of Contoured Poles to Foliation, Schistosity, Cleavage, Phyllitic Cleavage, Spaced Cleavage, Slaty Cleavage, and Shear Foliation Contour Interval = 2 sigma N = 547 Unidirectional Rose Diagram of Fractures (Joints) N = 301 Outer Circle = 6% Mean vector = 272 degrees MAJOR GEOLOGIC FEATURES 78*00' 00' 1 85 77*52’ 30" CZmmv ,/ Moss-Richardson Mo Deposit (Carpenter, 1 976) CZimv' CZmgs CZimv CZmmv, I CZfmgs /4 'CZimv H and H Mine (Carpenter, 1976) Sand and Gravel Abandoned CZimv CZmgs CZmwa/ Cataclasite CZimv 15' CZmgs Nash Brick 68j . 55 Company 7 Clay Pit Bridge CZmwa Saunders Cameteryi CZmms I CZfmgd / Aveht Cernatery CZfmgs j Aventon Avon Ion Posl OHice Do?ieit*N Lake Dam Gay Cemetery Ward y Cemetery CZmmv :-Ж©\ N\ ■' Argo Mine \ Д' (Carpenter, 1976)- Ricks Cemetery CZmmv Qemetery 1 №t*. ( 9 26' V 168 MILS 1c44' \ 31 MILS UTM GRID AND 2010 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET In Ы Momver Aurefcen Springs Centerville Essex Ringwood Castalia Red Oak Drake ADJOINING 7.5" QUADRANGLES SCALE 1:24 000 1 0.5 0 1 I I I I I I I I I I I — I Miles 1,000 500 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 III I I - I I - I I — I Feet 1 0.5 0 1 I — I I — I I — I I — I I — I I I Kilometers CONTOUR INTERVAL - 10 FEET Southern Essex geology mapped between September 2012 and May 2013. Field assistance provided by Barry Lumpkin and Eddie Hull. Northern Essex geology mapped between September 2014 and June 2015. PPMgm INTRODUCTION The Essex 7.5-minute Quadrangle lies in the easternmost North Carolina Piedmont. Fishing Creek, the Nash County - Halifax County line, crosses the quadrangle from west to southeast, dividing it into northern and southern portions. A small sliver of Warren County lies in the northwest corner of the quadrangle. South- and east-flowing Little Fishing Creek and Swift Creek cross the quadrangle near its northern and southern edges, respectively. The unincorporated crossroads communities of Ita and Essex (both in Halifax County), and Aventon (Nash County), are located in the area. The quadrangle is crossed by north-south NC Highway 43, which runs north-south between Rocky Mount and Hollister, and by east-west NC Highway 561 between Louisburg and Halifax. Nash Brick Company has clay pit operations in the region surrounding the Ita crossroads. The Government Complex of the Haliwa- Saponi Tribe is located near the northern edge of the quadrangle, along NC Highway 43/561; the Tribal School is just off the map in the southwestern corner of the Hollister Quadrangle. The southern portion of Medoc Mountain State Park and its hiking and horse trails occupy the northeastern corner of the quadrangle on both sides of Little Fishing Creek. Fishing Creek is primarily responsible for the drainage in the quadrangle. Its tributaries flow south in the northern portion of the quadrangle, and north in the southern portion. In the southern Essex Quadrangle, named tributaries of Fishing Creek are White Oak Swamp in the west, and Crooked Swamp, which flows generally eastward to join Fishing Creek near the eastern edge of the quadrangle. Little Fishing Creek, a major tributary, flows south to join Fishing Creek near the southeastern corner of the quadrangle. Powells Creek is a south-flowing tributary of Little Fishing Creek. Gideon Swamp drains much of the southwestern part of the Essex Quadrangle, and is itself a tributary of Swift Creek to the south. Natural exposures of crystalline rocks occur almost exclusively along these and numerous unnamed creeks, while the higher areas along drainage divides constitute broad generally flat surfaces that appear to be underlain by unconsolidated young sedimentary deposits. The elevations in the map area range from about 332 feet above sea level along Lynch-Hedgepeth Road (SR 1 330 in Halifax County) near the northwestern corner of the quadrangle and the Halifax-Warren County line, to less than 110 feet along Fishing Creek at the eastern edge of the quadrangle. PREVIOUS WORK Previous geologic investigations pertinent to the Essex Quadrangle include several regional and reconnaissance studies. Parker (1968) defined the structural framework of the region. Wilson and Spence (1979) produced a reconnaissance map of Nash County. A multi-county map by McDaniel (1980) includes Warren County. Farrar (1985a, b) mapped the entire eastern Piedmont of North Carolina, defined map units for the region, and proposed a stratigraphy and a tectonic model. A map of a four-quadrangle area by Stoddard and others (2009) includes the Centerville Quadrangle, just west of Essex. The Hollister Quadrangle (Boltin, 1985; Sacks and others, 2011 ) lies to the north of Essex, and the Red Oak Quadrangle (Stoddard and others, 2012) lies to the south. Additional mapping by Sacks (1999 and unpublished manuscript map), in a study of the Hollister fault zone, includes part of the eastern Essex Quadrangle, as does mapping and related research by Kite (1982). Other research relating to the geology of the Essex Quadrangle includes geophysical studies of the Hollister fault zone by Fletcher (1992) and by Lawrence (1999), a study of the sub-Coastal Plain basement (Lawrence and Hoffman, 1993), and a study of quartz-rich rocks in the area, interpreted as quartz arenites by Stanley (1978). A map by Weems and others (2009) shows surficial geology for the Roanoke Rapids 1:100,000 scale map, which includes the Essex Quadrangle. They show several surficial map units in the Essex Quadrangle. They also show the Thornburg fault, a high-angle fault with east side down, trending north -north east across the quadrangle, and constituting a scarp that separates two terraces of the Coastal Plain. DESCRIPTION OF MAP UNITS The pre-Mesozoic crystalline rocks of the Essex 1:24, 000-scale Quadrangle lie within either the Spring Hope or Roanoke Rapids terrane. The terrane-separating late Paleozoic and Alleghanian orogeny Hollister fault zone (Farrar, 1985b; Sacks, 1999) trends north-south near the eastern edge of the quadrangle. Most of these rocks were metamorphosed to the chlorite zone of the greenschist facies during Neoproterozoic and middle to late Paleozoic tectonothermal activity. In the extreme northwestern corner of the quadrangle, metamorphic conditions reached the biotite zone. Only Jurassic diabase dikes are not regionally metamorphosed. Minor contact metamorphic effects occur locally where diabase intrudes metasedimentary rocks. While subjected to this low-grade regional metamorphism and locally displaying fracture, foliation, and lineation, most prominently within and near the Hollister fault zone, most crystalline rocks preserve relict plutonic, volcanic, or volcanogenic sedimentary textures, which when combined with bulk rock compositions, allow for protolith identification. Therefore, the prefix "meta” is not included in the nomenclature of the pre-Mesozoic rocks described in the quadrangle. The classification and naming of sedimentary rocks in the Essex Quadrangle follows Walker and Cohen (2006), while igneous rocks uses the nomenclature of the International Union of Geological Sciences (IUGS) subcommission on the systematics of igneous rocks after Le Maitre (2002). Relict igneous textures, modal mineral assemblages, or normalized mineral assemblages when whole-rock geochemical data are available, provide the basis for naming meta-igneous units. Past regionally related maps and lithologic descriptions of McDaniel (1980), Kite (1982), Kite and Stoddard (1984), Farrar (1985a, b), and Stoddard and others (2009, 2012) assisted the development of the mapping results. The Spring Hope terrane underlies most of the quadrangle. Across the map area, its rocks are dominantly metasedimentary in nature, including mudstone, siltstone, and wacke-graywacke. Dacitic volcanic rocks dominate toward the north-central portion of the quadrangle. No fossils have been identified in the Spring Hope terrane, but radiometric ages on dacite range from 525 to 628 Ma (Goldberg, 1994; Horton and Stern, 1994; Coler and Samson, 2000; Stoddard and Miller, 2011). East of the Hollister fault in the Essex Quadrangle, the Roanoke Rapids terrane consists of the Halifax County mafic-ultramafic igneous complex (Kite, 1982; Kite and Stoddard, 1984). Metamorphosed granitoid intrusive rocks from elsewhere in the Roanoke Rapids terrane have been dated from 607 to 672 Ma (Horton and Stern, 1994; Coler and Samson, 2000). The Spring Hope and Roanoke Rapids terranes are inferred to represent elements of one or more Neoproterozoic-Cambrian oceanic island arcs of the peri-Gondwana realm (Hibbard and others, 2002, 2006). In some exposures, especially within the Hollister fault zone, highly partitioned strain produces variably fractured, cataclastic, phyllonitic, or proto my Ion itic and mylonitic rocks of meta-igneous and metasedimentary origin. Local outcrops of highly silicified or silicified-epidotized cataclasite rock have unclear protolith affinity. All the Cenozoic-aged geologic materials identified on the map have a detrital origin involving mud- to gravel-sized clasts and occur as part of Tertiary upland sediment deposits or Quaternary stream and floodplain deposits. INTRUSIVE ROCKS Jd - diabase. Melanocratic (Cl>80), dark gray to black, fine to medium aphyric to phyric, dense diabase consisting primarily of plagioclase, augite and locally olivine. May be plagioclase phyric. Occurs as dikes and sills and is typically seen as spheroidally weathered stream and hillside boulders and cobbles. Weathered surfaces are generally tan gray, grayish or brownish in color. Occurs in vertically to steeply dipping dikes. Red dashed lines link individual station locations where stream outcrops or boulders of diabase are exposed. Traces of larger dikes correlated with and extrapolated along strike using linear aeromagnetic anomalies. Red dots indicate isolated outcrops or float occurrences. PPmm - Medoc Mountain granite. Leucocratic (CI=5-7), tan to pink white to pink gray, medium phaneritic, xenomorphic equigranular biotite granite. Pavement outcrops are common east of Little Fishing Creek in Medoc Mountain State Park and east of Medoc Mountain Road where the Moss-Richardson molybdenite deposit was located (Carpenter, 1976). Only disturbed earth mounds now reflect this mine activity. The elongate and tabular stock crosscuts Hollister fault zone shear foliation in protomylonitic to mylonitic diorite gneiss of the Roanoke Rapids terrane. Numerous boulder fields and crosscutting tension fractures of bull quartz are located within the granite. Only locally is silicified granite(?) mylonitized and cataclastically fractured; however, some zones are several meters in length and width and always associated with the bull quartz tension fractures. Commonly, epidote blebs and a variable "pinking" overprint have been developed by the action of hydrothermal fluids on both K-feldspar and plagioclase. These are reminiscent of hydrothermal "pinking” events that affect other late Paleozoic and Alleghanian orogeny mylonite zones and granite plutons in the southern Appalachian orogen (Bartholomew and others, 2009; Dennis, 2010). PPMgm - granitoid rocks and metamorphosed and foliated granitoid rocks. Leucocratic (Cl<20), light tan, gray white to orange, or pinkish-white, medium to coarse phaneritic, hypidiomorphic to xenomorphic granular granite, granodiorite, or quartz diorite. Commonly foliated (S>L) and locally lineated (L>S) to produce protomylonitic to mylonitic granitoid gneiss containing relic feldspar porphyroclasts, quartz ribbons, and biotite aggregate mineral lineation (denoted as foliated granitoid, PPMfgm, in cross section). Individual samples may contain porphyroclastic magnetite crystals up to 3 mm in length. Locally, felsic minerals are altered to a dark gray color. Forms an elongate, tabular body within and adjacent to the late Paleozoic, Alleghanian orogeny Hollister fault zone. Granitoids appear to be intrusive into the rocks of the Halifax County complex within the Roanoke Rapids terrane. They may or may not be related to granitoid rocks of the Rocky Mount pluton (Spruill and others, 1987; Moncla, 1990; Stoddard and others, 2012) or to other granitoid rocks mapped by Sacks (1999 and unpublished). METAMORPHIC ROCKS OF THE SPRING HOPE TERRANE Note: Order of listed units does not imply stratigraphic sequence. CZfmv - Felsic metavolcanic rocks. Leucocratic (Cl <5), bluish gray, tan or white weathered, siliceous, aphanitic dacite tuff or porphyritic crystal dacite. Dacite is usually massive and ranges from fine ash to porphyritic plagioclase crystal tuff, as well as hypabyssal fine phaneritic intrusive rock. Contains a generally massive, relict aphanitic groundmass of plagioclase, quartz, and sparser K-feldspar. Locally may be quartz porphyritic. Metamorphic overprint and strain produce a weak phyllitic cleavage in some samples. Interpreted to have a pyroclastic or shallow intrusive origin. Unit is inferred to be correlative, at least in part, with felsic metavolcanic rocks (CZfmv) of Stoddard and others (2012) in the adjoining Red Oak 1:24K Quadrangle to the south, and the Gold Sand, Centerville, Castalia, Justice, and Hollister 1:24K Quadrangles to the west and north (Stoddard and others, 2009; Sacks and others, 2011). Includes distinctive gray, bluish-gray, tan, or white weathering, thinly layered and locally strongly fissile fine-grained layered felsic gneiss composed primarily of plagioclase, quartz, and microcline, with minor or accessory biotite, garnet, amphibole, epidote, white mica and opaque minerals, typically including significant magnetite. Rare relict phenocrysts of sodic plagioclase and/or quartz are locally present. Interpreted to be pyroclastic or lava in origin. Believed to be correlative with Bens Creek leucogneiss of Farrar (1985a, b), quartzite of McDaniel (1980), and "dacitic bluestone” of Stoddard (1993); Stoddard and others, 2009. The lithology includes dacitic to rhyolitic rocks based on analyzed samples from elsewhere (Stoddard, 1993; Stoddard and others, 2011 ; Sacks and others, 2011 ). Zircons from an exposure located in the north- central Centerville Quadrangle gave a discordant upper intercept U-Pb age of 524.9 +/- 8.6 Ma (Stoddard and Miller, 2011). This lithology is commonly associated with subordinate mafic metavolcanic rocks (CZmmv where shown on map). The CZfmv unit also includes light colored, generally fine grained and phyllitic to schistose rocks consisting of white mica, quartz, feldspar(s), chlorite, and rare biotite and epidote. Commonly contain relict phenocrysts of quartz (typically showing beta morphology) as well as sodic plagioclase, and/or white to beige and typically flattened lapilli. Interpreted as crystal- and crystal-lithic tuff. Large (to one cm) and somewhat flattened quartz phenocrysts locally give this lithologic type the field name “quartz-eye tuff." Chemical and petrographic data from the Bunn East Quadrangle (Stoddard, 1993) indicate that at least some of these rocks are rhyodacitic in composition, and locally have relict K-feldspar phenocrysts. Zircon crystals from felsic crystal tuff in the Bunn East Quadrangle have yielded a preliminary U-Pb upper intercept crystallization age of 590 +/- 3 Ma (Goldberg, 1994). Unit also includes tuffaceous metasedimentary rocks, as well as rare intermediate metavolcanic rocks, mineralogically similar to felsic varieties but with a higher percentage of epidote and/or biotite, taking on a darker hue or a salt-and-pepper appearance. CZimv - Intermediate metavolcanic and metaplutonic rocks. Diverse mesocratic (Cl=45) light green, greenish gray, bluish green, black green, light gray, gray, beige or brown, fine to medium grained, metamorphosed phaneritic to plagioclase, quartz, and/or hornblende-porphyritic rocks including microdiorite, andesite, quartz diorite, gabbro, diorite, granodiorite or quartz keratophyre. Typically unfoliated, but may be well jointed, gnarly weathered, silicified and/or brecciated. Includes variable proportions of epidote, biotite, chlorite, sericitic white mica, plagioclase, opaque oxides, K-feldspar, and titanite. Primary igneous hornblende, biotite and plagioclase are typically at least partly replaced by the metamorphic minerals epidote, white mica, biotite, chlorite and opaque oxides. Pyrite cubes are locally abundant. Locally spheroidally weathered; rarely well foliated and slaty or phyllitic. May represent dikes, sills, or lava flows, at least in part, as well as plutons. Unit is inferred to be correlative with intermediate metavolcanic rocks (CZimv) of Stoddard and others (2012) in the adjoining Red Oak 1:24K Quadrangle to the south, and potentially with the rare occurrences of intermediate metavolcanic rocks (included with CZfmv) reported to the west and southwest in the Centerville and Castalia 1 :24K Quadrangles (Stoddard and others, 2009). CZmmv - Mafic metavolcanic rocks: Green, dark green, or black, fine to medium grained, massive and non-foliated or weakly to moderately foliated amphibolite, greenstone, phyllite, and quartz-epidote rock containing various mixtures of hornblende, plagioclase, epidote/clinozoisite, quartz, chlorite, and opaque minerals. Locally includes metabasalt having relict plagioclase phenocrysts and amyduloidal texture, and rare metagabbro with relict clinopyroxene. Chemical analyses of mafic metavolcanic rocks of the Spring Hope terrane in the Hollister Quadrangle (Sacks and others, 2011) plot as low-K tholeiite and are inferred to have ocean-floor or island-arc affinities (Boltin, 1985; Boltin and Stoddard, 1987). CZmwa - Metamorphosed quartz wacke. Primarily grayish green, light greenish to medium brown or gray, fine- to medium-grained feldspathic wacke. Individual exposures are generally massive and poorly bedded. Higher clay mineral content in feldspathic wacke indicates a higher abundance of seriticized feldspar relative to quartz in arenite, which overall has a better preserved vitreous luster of individual quartz grains. Abundant fragments and rounded quartz, plagioclase, and microcline grains, as well as small volcanic lithic fragments highlight its relict clastic texture. Their sedimentary characteristics suggest that these rocks may have originated as turbidite deposits, perhaps as distal drape aprons on the flanks of local volcanic centers associated with CZmgs. Unit is inferred to be map-scale horizons that are correlative with metagraywacke (CZmgs) of Stoddard and others (201 2) in the adjoining Red Oak 1 :24K Quadrangle to the south, as well as to the west and southwest in the Centerville and Castalia 1 :24K Quadrangles, respectively (Stoddard and others, 2009). CZmgs - Metamorphosed siltstone, mudstone, and interlayered feldspathic wacke. Mostly greenish tan, beige, or gray, fine grained and phyllitic, fissile siltstone, light tan to medium brown, massive and phyllitic mudstone, and local interlayers of light greenish to medium brown or gray, fine- to medium -grained feldspathic wacke. Contains a matrix of fine-grained quartz, plagioclase, white mica, and locally sparse biotite and opaque minerals. May locally preserve a relict clastic texture and sedimentary bedding. Unit is commonly tuffaceous and includes unmapped interlayers of felsic volcanic rocks. Siltstone and mudstone eposures may weather slabby and have a high clay mineral content indicating the relative abundance of feldspar versus quartz. Cyclic bedding and graded bedding are preserved locally, although individual exposures of feldspathic wacke and quartz arenite are more massive and poorly bedded. Higher clay mineral content in feldspathic wacke indicates a higher abundance of seriticized feldspar relative to quartz, which overall has a better-preserved vitreous luster of individual quartz grains. Abundant fragments and rounded quartz, plagioclase, and microcline grains, as well as small volcanic lithic fragments highlight a relict clastic texture in the wacke. Their sedimentary characteristics suggest that these rocks may have originated as turbidite deposits, perhaps as distal drape aprons on the flanks of local volcanic centers. Along the eastern contact of the unit, high strain is associated with the late Paleozoic Alleghanian orogeny in the Hollister fault zone. It results in a subvertically dipping phyllonitic schistosity in outcrop (denoted as foliated siltstone and mudstone, CZfmgs, in cross section and map). There are also rare exposures of granular and/or sucrosic, fine to medium-grained, and locally conglomeratic pure quartz rocks. These have been interpreted by Stanley (1978) interpreted some horizons as metamorphosed quartz arenite resulting from residual accumulations of quartz phenocrysts weathered out of felsic volcanic rocks in pocket beach environments of the volcanic island-arc. However, because of a general lack of apparent primary sedimentary structures, these rocks may instead have resulted from recrystallization of zones of hydrothermal quartz alteration. The conglomeratic rocks primarily contain polycrystalline quartz pebble clasts in a finer grained polycrystalline quartz matrix. Zircon crystals from an unmapped dacite crystal tuff layer within metasedimentary rocks in the southeastern Centerville Quadrangle yield a nearly concordant U-Pb age of 628 +/- 1.7 Ma (Stoddard and Miller, 2011). Unit is inferred to be correlative with metasiltsone, metagraywacke, and metamudstone (CZmgs) of Stoddard and others (2012) in the adjoining Red Oak 1:24K Quadrangle to the south, as well as to the west and southwest in the Centerville and Castalia 1:24K Quadrangles, respectively (Stoddard and others, 2009). CZmms - Metamorphosed mudstone and siltstone. Subunit of CZmgs in which fine-grained sedimentary rocks dominate. CZmcg - Metamorphosed conglomerate: Subunit of CZmgs characterized by exposures of pebbly wacke and conglomerate. Conglomerate contains clasts of mono- and polycrystalline quartz, feldspars, and likely volcanic clasts, up to one cm. Conglomerate appears to be matrix- supported; mica-rich matrix contains chlorite, epidote and opaque oxides, including magnetite. METAMORPHIC ROCKS OF THE ROANOKE RAPIDS TERRANE PPMfgm CZfmv CZimv CZmmv CZmwa CZmgs CZfmgs CZmms CZmcg CZmgd CZfmgd “T 777 yAffiii REFERENCES Note: Order listed does not imply stratigraphic sequence. Halifax County complex CZmgd - Metamorphosed gabbro/diorite and basalt/microdiorite. Melanocratic to mesocratic (CI=40-80), black to dark green to light greenish gray, medium-grained gabbro and diorite. Unfoliated outcrops contain plagioclase and hornblende, epidote or clinozoisite, opaque oxide minerals, and locally quartz and sulfide minerals. Preserves a relict phaneritic texture between blocky plagioclase and tabular hornblende. Presence of uralite in irregular xenomorphic hornblende or actinolite suggests that these crystals may be psuedomorphs after magmatic clinopyroxene in gabbro. Other relict phaneritic samples display interlocking, xenomorphic to hypidiomorphic granular plagioclase and hornblende that are interpreted to be magmatic diorite. Fine-grained equivalents are interpreted to be basalt, in some cases now amphibolite, and microdiorite that preserve either an aphanitic to fine phaneritic igneous texture. Scattered outcrops of quartz diorite, hornblende tonalite, trondhjemite, and locally granodiorite are intimately associated with the gabbro/diorite and are interpreted to be more quartz-rich and differentiated magmatic rocks of the Halifax County complex. Where overprinted by the late Paleozoic Alleghanian orogeny Hollister fault zone, steeply dipping chlorite-rich phyllonite, mylonite, and gabbro/diorite gneiss protomylonite are produced from the original igneous protoliths (denoted as foliated gabbro/diorite, CZfmgd, in cross section). Unit is inferred to be correlative with mafic to intermediate rocks of the Halifax County complex of Kite (1982) and Kite and Stoddard (1984), as well as metagabbro (CZhmg) and metabasalt (CZhmb) of the Halifax County complex mapped by Stoddard and others (2012) in the adjacent Red Oak 1 :24K Quadrangle just to the south. CZmpx - Metamorphosed pyroxenite cumulate. Melanocratic (Cl>80), pale to dark green, medium grained, massive pyroxenite. Blocky actinolite porphyroblasts up to 7 mm in diameter display uralite, suggesting a pseudomorph of original magmatic cumulate pyroxene crystals that have been replaced by mats of actinolite prisms during metamorphic recrystallization. Pale green clinozoisite is interstitial to the actinolite and may reflect the reaction replacement of intercumulate plagioclase in the original igneous ultramafic rock. Forms an undeformed pod or phacoid of ultramafic rock and gabbro/diorite surrounded by deformed and foliated gabbro/ diorite of the Halifax County complex within the late Paleozoic Alleghanian orogeny Hollister fault zone along Powells Creek due west of its confluence with Little Fishing Creek. Another pod Zone of high strain overprint of Hollister fault zone Bartholomew, M. J., M. A. Evans, F. J. Rich, В. M. Brodie, and R. D. Heath, 2009, Rifting and drifting in South Carolina: Fracture history in Alleghanian granites and Coastal Plain strata: Carolina Geological Society Guidebook, 50 p. 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Dennis, 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, p. 299-339. Hibbard, J., van Staal, C., Rankin, D., and Williams, H., 2006, Lithotectonic map of the Appalachian orogen (South), Canada-United States of America: Geological Survey of Canada Map 02096A, scale 1:1500000. Horton, J. W., Jr., and T. E. Stern, 1994, Tectonic significance of preliminary uranium-lead ages from the eastern Piedmont of North Carolina: Geological Society of America Abstracts with Programs, v. 26, p. 21. Kite, L. E., 1982, The Halifax County complex: Oceanic lithosphere in the northeastern Piedmont, North Carolina: [M.S. thesis], North Carolina State University, Raleigh, North Carolina, 102 p. Kite, L. E., and E. F. Stoddard, 1984, The Halifax County complex: Oceanic lithosphere in the eastern North Carolina Piedmont: Geological Society of America Bulletin, v. 95, p. 422-432. Lawrence, D. P, 1999, Bouguer gravity study along the Hollister fault zone, eastern North Carolina, in Sacks, P. E. (ed.), Geology of the Fall Zone region along the North Carolina-Virginia state line: Carolina Geological Society Field Trip Guidebook, p. 37-48. Lawrence, D. P, and C. W. Hoffman, 1993, Geology of basement rocks beneath the North Carolina Coastal Plain: North Carolina Geological Survey Bulletin 95, 60 p. 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, 252p. McDaniel, R. D., 1980, Geologic map of Region K: North Carolina Department of Natural Resources and Community Development, Geological Survey Section, Open File Map NCGS 80-2 [scale 1 :100,000], Moncla, A. M., Ill, 1990, Petrography, geochemistry, and geochronology of the Rocky Mount batholith, northeastern North Carolina Piedmont: [M.S. thesis], East Carolina University, Greenville, NC, 61 p. Parker, J. M., Ill, 1968, Structure of easternmost North Carolina Piedmont: Southeastern Geology, v. 9, p. 117-131. Sacks, P. E., 1999, Geologic overview of the eastern Appalachian Piedmont along Lake Gaston, North Carolina and Virginia, in Sacks, P. E. (ed.), Geology of the Fall Zone region along the North Carolina-Virginia state line: Carolina Geological Society Field Trip Guidebook, p. 1-15. Sacks, P. E., W. R. Boltin, and E. F. Stoddard, 2011 , Bedrock geologic map of the Hollister 7.5-minute quadrangle, Warren and Halifax Counties, North Carolina, North Carolina: North Carolina Geological Survey Open-file Report 2011-03, scale 1:24,000, in color. Spruill, R. K., Lawrence, D. P, and Moncla, A. 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EXPLANATION OF MAP SYMBOLS contact - location known contact - location inferred CONTACTS, FAULTS AND FOLDS Lithologic contacts - Distribution and concentration of structural symbols indicates degree of reliability. - ductile fault - location inferred d - J- - anticline, plunging A in cross section, ductile fault - (A indicates movement away from observer, d - 1 - syncline, plunging T T indicates movement towards observer) WHOLE ROCK CHEMISTRY OF SELECTED SAMPLES INDEX TO GEOLOGIC MAPPING This map supersedes NCGS Open File Report 2013-04, Bedrock Geologic Map of the Southern Portion of the Essex 7.5-minute Quadrangle, Halifax, Nash and Warren Counties, North Carolina OXIDES IN V WEIGHT PERCENT TRACE ELEMENTS IN PARTS PER Ml LLION SAMPLE ID ROCK TYPE MAP UNIT SOURCE Si02 Ti02 AI203 Fe203 MnO MgO CaO Na20 K20 P205 L.O.I. Total Rb Sr Zr Cr Ni LKE133F gabbroid CZmgd К 46.09 0.61 16.65 8.57 0.17 10.40 10.92 2.21 0.69 0.11 3.4 99.82 41 nd 49 262 105 LKE135F gabbroid CZmgd К 42.26 0.20 19.00 9.06 0.19 11.95 10.67 1.11 0.20 0.04 3.7 98.38 17 nd 20 205 80 LKE152F quartz diorite CZmgd К 59.35 0.81 14.13 9.91 0.20 4.79 6.67 420 046 0.33 nd 100 85 37 174 50 50 8 Analyses by X-ray fluorescence spectrometry; North Carolina State University Total Fe as Fe203; tr=trace; nd=not determined L.O.I. = percent weight loss on ignition source: K= Kite and Stoddard (1984) Little Fishing HOLLISTER Fishing Creek FAULT Creek 200' O' 2000' 4000' cross section scale - 1 :24 000 no vertical exaggeration s У 41 w У У @ LINEAR FEATURES 11 ^ bearing and plunge of crenulation lineation 23 \ bearing and plunge of mineral lineation PLANAR FEATURES bearing and plunge of slickenline lineation bearing and plunge of fold hinge strike and dip of primary layering strike and dip of primary layering (multiple observations at one location) strike and dip of compositional layering V 45 V/ У strike and dip of inclined undifferentiated shear strain foliation strike and dip of inclined undifferentiated shear strain foliation (multiple observations at one location) strike of vertical undifferentiated shear strain foliation strike and dip of compositional layering (multiple observations at one location) strike of vertical undifferentiated shear strain foliation (multiple observations at one location) strike of vertical compositional layering (multiple observations at one location) strike and dip of inclined regional phyllitic cleavage/weak schistosity strike and dip of overprinting cleavage strike and dip of overprinting cleavage (multiple observations at one location) strike and dip of inclined regional phyllitic cleavage/weak schistosity (multiple observations at one location) strike of vertical regional phyllitic cleavage/weak schistosity /^70 strike and dip of crenulation cleavage strike and dip of spaced cleavage strike of vertical regional phyllitic cleavage/weak schistosity (multiple observations at one location) strike and dip of spaced cleavage (multiple observations at one location) horizontal regional cleavage/weak schistosity strike of vertical spaced cleavage (multiple observations at one location) OTHER FEATURES У 75 V/ У / У У 2v strike and dip of inclined joint/fracture surface strike and dip of inclined joint/fracture surface (multiple observations at one location) strike of vertical joint surface strike of vertical joint surface (multiple observations at one location) strike and dip of inclined slickenline surface strike of quartz vein, dip unknown strike of vertical quartz vein strike of vertical diabase dike strike and dip of axial surface of mesoscale fold strike and dip of inclined mesoscale fault X clay pit © station location H sucrosic and friable quartz X clay pit - abandoned • diabase station location A cataclasite n mine or prospect И Tertiary upland sediment location Д location of bull quartz debris and/or veins — diabase dike - location inferred diabase dike - location concealed in cross section, diabase dike BEDROCK GEOLOGIC MAP OF THE ESSEX 7.5-MINUTE QUADRANGLE, NASH, HALIFAX AND WARREN COUNTIES, NORTH CAROLINA By David E. Blake, Edward F. Stoddard, Daniel L. Rhodes, and Robert H. Morrow Digital representation by Michael A. Medina, Heather D. Hanna and Philip J. Bradley 2015 A A' cross section line area of abundant quartz cataclasite LKE133FA 0 geochemical station location Base map is from USGS 2010 GeoPDF of the Essex 7.5-minute quadrangle. Aerial photo, map collar and select features removed. Bounds of GeoPDF based on 7.5-minute grid projection in UTM 17S; North American Datum of 1983 (NAD83). This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program, award numbers G12AC20308 and G14AC00230. 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. 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. Disclaimer: This Open-File report is preliminary and has been reviewed internally for conformity with the North Carolina Geological Survey editorial standards. Further revisions or corrections to this preliminary map may occur. Scan with smartphone for link to GeoPDF of map. Third party App required. BEDROCK GEOLOGIC MAP OF THE ESSEX 7.5-MINUTE QUADRANGLE, NASH, HALIFAX AND WARREN COUNTIES, NORTH CAROLINA NCGS OPEN FILE REPORT 2015-01