Geologic map of the Moncure 7.5-minute quadrangle, Lee and Chatham counties, North Carolina

North Carolina Department of Environmental Quality Division of Energy, Mineral and Land Resources Brian L. Wrenn, Division Director Kenneth B. Taylor, State Geologist This Geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program ro c i_ 0 -t— ■ я О Я '■c. dg Qal Qtl Qth disturbed ground alluvium terrace deposits - low terrace deposits - high Correlation of Map Units Tphms Heavy Mineral Bearing Sand о 'o N О CO 0 Km (?) Middendorf Formation (?) diabase Triassic Sedimentary Rocks Deep River Basin: Sanford Sub-basin Sanford Formation Cumnock Formation Pekin Formation Trs Deep River Basin: Durham Sub-basin Lithofacies Association Trcs/c Trcs Trp Trcs/si2 Trcsi/s Lithofacies Association о 'o N 2 0 • 2 Q_ О 0 Aaron Formation Youngest detrital zircons of ca. 588 and 578 Ma (Pollock et al., 2010 and Samson et al 2001, respectively) Za Hyco Formation - upper member 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) Easternmost Carolina Terrane CZbg Discordant zircons ages of 573, 574, and 579 Ma and an upper intercept age of 575 ±12 Ma, interpreted as the time of crystallization (Goldberg, 1994) for a sample of Big Lake-Raven Schist in the Cary Quadrangle. CZbr3 Zhime/pl Zhdlt (u) Stratigraphic relations uncertain INTRODUCTION The Moncure 7.5-minute Quadrangle lies in the east central-portion of the North Carolina Piedmont. In Chatham County, the unincorporated communities of Moncure, Haywood and Brickhaven are present within the quadrangle. In Lee County, the unincorporated communities Blacknel and Osgood are present. The local transportation corridor US HWY 1 cuts across the northwest portion of the quadrangle. NC HWY 42 cuts diagonally across the map in the southeast portion of the quadrangle. The Cape Fear River controls the drainage in the quadrangle. The Deep and Haw Rivers join to form the Cape Fear River in the northern portion of the quadrangle. The smaller tributaries of Shaddox Creek, Gulf Creek, Wombles Creek, Little Shaddox Creek, Lick and Bush Creek flow directly to the Cape Fear. Natural exposures of crystalline and Triassic rocks, as well as younger Quaternary sediments, 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 470 feet above sea level near the south-central edge of the quadrangle where Coastal Plain sediments cap metamorphic and Triassic-aged rock units, to approximately 160 feet in the Cape Fear River channel on the east-central edge of the quadrangle. Geologic Background In the northwestern corner of the Moncure Quadrangle, the crystalline rocks are part of the redefined Hyco Arc and Aaron Formation (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 of the redefined Virgilina sequence (Hibbard et al., 201 3). The Hyco Arc consists of the Hyco Formation which include ca. 633 to 612 Ma (Wortman etal., 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 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 et al., 2001 , respectively). Hibbard et al. (201 3) interprets an at least 24 million year unconformity between the Aaron and underlying Hyco Formation. The southeastern corner of the quadrangle is underlain by metamorphosed crystalline rocks of the Cary sequence (Parker, 1979; Farrar, 1985). The Cary sequence is interpreted to be part of the Carolina terrane but separated from the rest of the terrane by the Triassic basin (Hibbard et al., 2002). For this map, related rocks are identified as being part of the Easternmost Carolina terrane. One of the main rock units is the Big Lake-Raven Rock schist. In the Cary Quadrangle, a sample from the unit yielded, discordant 207Pb/206Pb zircons ages of 573, 574, and 579 Ma and an upper intercept age of 575 ±12 Ma, interpreted as the time of crystallization (Goldberg, 1994). This is a similar age to the Aaron Formation. The central portion of the quadrangle is underlain by Triassic-aged sedimentary rocks of the Deep River Mesozoic basin which is separated into three sub-basins (Durham, Sanford and Wadesboro). The Colon cross structure (Campbell and Kimball, 1923 and Reinemund, 1955), partially located within the quadrangle, is a constriction zone in the basin characterized by crystalline rocks overprinted by complex brittle faulting. The Colon cross-structure marks the transition between the Durham and Sanford sub¬ basins. The Colon Quadrangle contains the Triassic-aged units from oldest to youngest of the Pekin, Cumnock and Sanford Formations of the Sanford sub-basin. Detailed descriptions of the Triassic sediments are provided in Reinemund (1955). A detailed comparison of the Durham and Sanford sub¬ basins is provided in Clark et al. (2001). Dikes of Jurassic aged diabase intrude the Triassic sediments and crystalline rocks of the map area. Coastal Plain sediments are present in the southern portion of the quadrangle. Quaternary aged alluvium is present in most modern river valleys, with at least two levels of fluvial terraces along the major drainages. These terraces, where preserved, mark the location and elevation of ancestral river systems, prior to incision to the modern floodplain levels. 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. 79 00' 00" 35 45' 00" Faults Abundant evidence of brittle faulting at the outcrop-scale, map-scale and large-scale lineaments (as interpreted from hillshade LiDAR data) are present in the area. The quadrangle includes the eastern portion of the Colon cross¬ structure that marks the transition between the Durham and Sanford sub-basins. The brittle faulting and lineaments are interpreted to be associated with Mesozoic extension. A fault bounded block with in the Carolina terrane (in the northwest corner of the Moncure Quadrangle and southwest corner of the Merry Oaks Quadrangle) has been identified with rotated metamorphic foliations up to 70 degrees clockwise. This rotation is speculated to be related to rotation of a breeched relay ramp. Past Work Reinemund (1955), is an important work, that has laid the foundation for the geology with in the Triassic basin. For this mapping effort, Reinemund’s maps were georeferenced to a digital elevation model from Hillshade LiDAR. Geologic contacts within the Triassic basin were digitized and modified, if needed. Most of the geology south of the Cape Fear River within the Triassic basin was digitized as presented by Reinemund. The northeast corner of the Moncure Quadrangle is situated in the transition between the Durham and Sanford sub-basins. In the Sanford sub-basin, a three-layer stratigraphy has been identified and formalized from oldest to youngest as the Pekin, Cumnock and Sanford Formations (Campbell and Kimball, 1923 and Reinemund, 1955). In the Durham sub-basin, this three-layer system is not recognized. Previous mapping by North Carolina Geological Survey staff separated the Durham sub-basin into lithofacies associations using the nomenclature of Smoot et al. (1988). Hoffman and Gallaghar (1989) began using the lithofacies association nomenclature and it was subsequently adopted for all mapping in the Durham sub-basin. The formation mapping of Reinemund (1955) in the Sanford sub-basin and the lithofacies association mapping in the Durham sub-basin are incompatible (Clark et al., 2001). These two methods of mapping meet in the Moncure and Merry Oaks Quadrangles. The detailed investigation of the contrasting mapping methods and establishment of a unified stratigraphic nomenclature for the Sanford and Durham sub-basins is out of the scope of this mapping project. As such, the map units from the adjacent Cokesbury Quadrangle (Butler et al., 2016) were extended into Moncure to mark the change of unit nomenclature from the Sanford sub-basin to the Durham sub¬ basin. Additional work is needed to establish a new stratigraphic nomenclature for the entire Deep River basin. Heckert et. al (2012) presented the results of a microroinvertebrate fossil analysis of Triassic sediments from a clay pit within the quadrangle. The sediments are interpreted to belong to the Cumnock Formation and extend the eastward extent of the Cumnock Formation map unit compared to that of Reinemund (1955). Monitoring well boring location data from the Comprehensive Site Assessment Report for the Duke Energy Cape Fear Steam Electric Plant (SynTerra, 2015) is included on the map. Boring data includes bedrock rock type and thickness of surficial material. Mineral Resources Clay Products and Crushed Stone The red claystones of the Pekin and Sanford Formations continue to supply area brick manufactures raw material. In the 1950's, it was reported that multiple brick and tile producers were active in the nearby area (Reinemund, 1955). It has been and continues to be an important location for clay products. Six abandoned and one active clay pits are present in the map and are identified. One active crushed stone quarry is in operation in the northwest corner of the quadrangle. Coal Deposits Coal has been mined within the region since before the Revolutionary War - ca. 1750’s. Reinemund (1955) estimates the total production in the Deep River Coal Field exceeded 1 million tons. The majority of the production was from two mines with extensive underground workings in the adjacent Colon Quadrangle. Reinemund (1955) identified a limited coal outcrop area and two former coal pits north of the community of Brickhaven within the Moncure quadrangle. Reinemund (1955) provides an extensive review of the coal deposits and geology of the Deep River Coal Field. Oil and Gas Potential Natural gas exploration well NCCM-2 was drilled east of the coal outcrop area in 1981 by North American Exploration to a depth of 250 feet. Several other natural gas exploration wells have been drilled in the nearby Goldston Quadrangle. A summary of the natural gas potential of the Sanford sub-basin is provided in Reid et al. (2011). A compilation map showing seismic lines, drill holes and hydrocarbon shows is provided in Reid et al. (2010). An overview of the Triassic rift / lacustrine basins, their hydrocarbon potential in North Carolina, a regulatory framework overview and data access information can be found in Reid et al. (2018). Quaternary Deposits Quaternary deposits in the Moncure Quadrangle were previously mapped by Reinemund (1955), along with bedrock mapping; however, the mapping was conducted prior to 1:24,000 topographic map availability. The Quaternary mapping for this project utilized digital county soil survey parent material maps (Soil Survey Staff, 2019), high resolution LiDAR surface topography, data from Reinemund (1955), and new field observations (outcrops and hand augers). The Quaternary fluvial sediments were divided into 3 map units (modern floodplain and two terrace levels). Three terrace levels had been mapped by Reinemund (1955); however, Reinemund’s lowest terrace level occurs in large part on the modern floodplain, based on LiDAR and soil survey mapping. Due to practical considerations and mappability at the 1 :24,000 scale, we chose to map only two terrace levels (Qth and Qtl), similar in concept to mapping in quadrangles immediately to the west by Bradley et al. (2020) and Rice et al. (2020). The oldest and highest terrace deposits (Qth) contains fluvial deposits in an ancestral Haw River, Deep River, and Cape Fear River system that has since incised to its present level. The elevation of this terrace level in the Moncure Quadrangle ranges from as high as 265 feet to 190 feet asl, typically about 40 to 100 feet above the modern floodplain. There are likely multiple terrace levels within this map unit that we chose to not differentiate because of the high degree of dissection and because lithological differences were not readily observed. Possible causes for the river’s overall incision during the Quaternary include tectonic, glacial isostatic adjustment (forebulge of Laurentide Ice Sheet) and climatic processes. The age of deposits within the high terrace unit are speculatively middle Pleistocene based on the terrace height above the modern floodplain (Mills, 2000), degree of dissection, and weathering characteristics (Suther et al., 2011). Deposits of Qth are only mapped where thicker than about 1 .5 feet (0.5 m). Areas with thinner Qth deposits may be present locally in the Moncure Quadrangle at similar elevation ranges, typically in a strath terrace underlain by Triassic residuum and bedrock. In some areas, in-situ weathering of Triassic sandstone or conglomerate can result in soil profiles with loamy sand or gravelly sand textures that resemble terrace deposits. The terraces deposits themselves are in part reworked from weathered Triassic bedrock. Thus, differentiation of these materials can be difficult within the soil profile, but may be based on the sharpness of the contact, the presence of a basal gravel lag, or an unconformity. The low terrace deposits (Qtl) contain younger Cape Fear River Basin fluvial deposits, with terrace elevations ranging from 210 feet to 170 feet asl, typically about 10 to 30 feet above the local modern floodplain. The age of deposits within the low terrace unit are speculatively late Pleistocene to early Holocene based on the terrace height above the modern floodplain (Mills, 2000; Suther et al., 2011 ). Deposits of the low terrace are generally fine-grained and can be more than 1 5 feet thick. About 6 feet of low terrace deposits overlie more altered Qth fluvial deposits at a railroad cut east of Corinth Road and south of Brickhaven. At least 20 feet of fine-grained (silty clay, silt and fine sand) deposits occur underneath the low terrace east of the Haw River, near a slight bend in Corinth Road where Reichhold Chemical Superfund site (NC DEQ Site ID NCD04 9845548) was located. Alluvial deposits on the modern (Holocene) floodplain (Qal) consist mainly of silt loam to silty clay loam in modern river valleys within in the Triassic Basin. Fine to medium sand occurs in points bars and river channels, along smaller creeks in crystalline terrain (where it can be gravelly) and likely at depth from reworking of Pleistocene and older sediments. Along the Deep-Haw-Cape Fear River valleys, the modern floodplain ranges in elevation from about 190 feet asl (Deep River valley) to 160 feet asl (Cape Fear River valley on eastern edge of quadrangle). This map unit likely also includes very low terraces which are blanketed by modern overbank flood deposits from times of high water levels. 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. Dikes of Jurassic-aged diabase intrude the crystalline rocks and Triassic sediments of the map area. Triassic-aged sediments and Jurassic diabase dikes are not metamorphosed. Quaternary aged alluvium is present in most major drainages. 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). Crystalline rock unit descriptions common to Bradley et al. (2020) from the Colon geologic map, 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 Units 35 37' 30 79 07' 35 37' 30" 30" 79 00' 00" dg Qal Qtl Qth Tphms Km (?) Trsc Trs Trcs Trcs/c Trc Trcsi/s Trcs/si2 Trp Za Zhime/pl Zhdlt (u) CZbg CZbr3 dg - Disturbed ground: consists of fill in highway embankments, railway embankments, industrial areas and mine spoil piles, as well as areas of removed earth in mined-out-areas (clay pits) and coal ash ponds. Qal - Modern (Holocene) floodplain deposits: silt loam to silty clay loam, with fine to medium sand deposits in point bars and channels deposits; smaller tributaries in the Carolina terrane can have more sandy or gravelly alluvium; brown to reddish brown to grayish brown; soft; crudely stratified; observed at least 9 feet thick, but maximum thickness unknown. Includes very low terraces that are periodically inundated by modern floods. Contains weak to moderately developed soil profiles. Structural measurements depicted on the map within Qal represent outcrops of crystalline rock inliers surrounded by alluvium. Qtl - Quaternary low terrace deposits: silt loam to silty clay loam to loamy fine sand; generally does not contain gravel, but may contain a thin lag of gravel near unit base; yellowish brown to brown to light gray; in some areas is difficult to differentiate from high levels of modern floodplain; ranges from 2 feet to more than 20 feet thick Qth - Quaternary high terrace deposits: sandy clay loam to gravelly loamy sand to gravelly sand; yellowish brown to reddish brown; gravel consists primarily of white, rounded to subrounded quartz pebbles, with rare cobbles; the fluvial depositional sequence generally fines upwards, with gravelly zones typically revealed along eroding slopes; total thickness of map unit is typically 2 to 1 0 feet; may consist of a lag deposit in strath terraces over a red, silty clay to clay residuum developed into fine-grained Triassic bedrock. Mapped areas may include multiple, undifferentiated high terrace levels. Contains E and Bt horizons of an Ultisol soil profile, with significant alteration extending several feet into the unit. May exhibit crude stratification or cross bedding at depth, [this unit is similar in concept to Qg3 of Reinemund (1955)] Coastal Plain Deposits Tphms - Heavy Mineral Bearing Sand: silty and clayey; reddish brown, tan, and gray; fine- to very- coarse grained; poor to moderately poor sorting; subangular to rounded quartz sand. Locally quartz gravel is present. Contains rare heavy minerals (dominantly a suite with staurolite, dravite and rutile); rare mica; rare rose quartz. Massively bedded, rarely laminated. Near surface mottling usually obscures sedimentary structures. Basal contact is erosional. Unit is of probable Pliocene age. Description modified from the adjacent Cokesbury Quadrangle geologic map (Butler et al., 2016). Km (?) - Middendorf Formation (?): unconsolidated white sand with brown silt and clay. Locally quartz gravel to small cobbles present. Identified as Tertiary-aged high level surficial deposits by Reinemund (1955) and identified as the Middendorf Formation on the Geologic Map of North Carolina (NCGS, 1985). Intrusive Unit 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. Triassic Sediments of the Deep River Basin Chatham Group Trsc - Conglomerate of the Sanford Formation: mainly conglomerates with fragments of metamorphic rock and quartz embedded in and interbedded with red mudstone, siltstone and sandstone (Reinemund, 1955). Equivalent to Tree of Lithofacies Association III in the Cokesbury Quadrangle. Trs - Sanford Formation: mainly red to brown, locally purple, coarse-grained, arkosic sandstones and conglomerates. Subordinate amounts of claystone, siltstone and fine-grained sandstone (Reinemund, 1955). Tree - Conglomerate of Lithofacies Association ill: reddish-brown to dark brown, irregularly bedded, poorly sorted, cobble to boulder conglomerate. Muscovite is rare to absent in the very coarse-grained to gravelly matrix. An arbitrary cut-off of greater than 50 percent conglomerate distinguishes this unit from the Trcs/c facies. Clasts are chiefly miscellaneous felsic and intermediate metavolcanic rocks, quartz, epidote, bluish- gray quartz crystal tuff, muscovite schist, and rare meta-granitic material. Maximum clast diameters are in excess of 2 m locally. Equivalent to Trsc and included in quadrangle to edge-match with the Cokesbury Quadrangle. Trcs - Interbedded sandstone and pebbly sandstone of Lithofacies Association III: reddish-brown to dark brown, irregularly bedded to massive, poorly to moderately sorted, medium- to coarse-grained, muddy lithic arkoses, with occasional, matrix-supported granules and pebbles or as 1-5 cm thick basal layers. Muscovite is common to absent. Occasional bioturbation is usually surrounded by greenish-blue to gray reduction halos. Beds are tabular, 1-3 meters thick, with good lateral continuity. Unit grades eastward into Trcs/c. Extended into Moncure from Cokesbury Quadrangle. Trcs/c - Sandstone with interbedded conglomerate of Lithofacies Association III: reddish-brown to dark brown, irregularly bedded, poorly sorted, coarse-grained to pebbly, muddy lithic sandstones with interbedded pebble to cobble conglomerate. Muscovite is rare to absent in the matrix. Well-defined conglomerate beds distinguish this unit from conglomerate basal lags of Trcs. An arbitrary cut-off of less than 50 percent conglomerate distinguishes this unit from the Tree conglomerate facies. Conglomerate beds are channel-shaped and scour into the underlying sandstone beds. Unit grades eastward into Tree. Extended into Moncure from Cokesbury Quadrangle. Trc - Cumnock Formation: gray and black claystone, shale and siltstone. Gray sandstone. Contains beds of coal and carbonaceous (organic-rich) shale (Reinemund, 1955). Includes coal horizons. Trcsi/s - Siltstone with interbedded sandstone of Lithofacies Association II: reddish-brown, extensively bioturbated, muscovite-bearing, siltstone interbedded with tan to brown, fine- to medium-grained, muscovite-bearing, arkosic sandstone, usually less than one meter thick. Siltstones can contain abundant, bedded, calcareous concretions (interpreted as caliche) and iron nodules. Bioturbation is usually surrounded by greenish-blue to gray reduction halos. Extended into Moncure from Cokesbury Quadrangle. Portions of unit may correlate with the Cumnock and Pekin Formations. Trcs/si2 - Sandstone with interbedded siltstone of Lithofacies Association II: cyclical depositional sequences of whitish-yellow to grayish-pink to pale red, coarse- to very coarse-grained, trough cross-bedded lithic arkose that fines upward through yellow to reddish-brown, medium- to fine-grained sandstone, to reddish-brown, burrowed and rooted siltstone. Bioturbation is usually surrounded by greenish-blue to gray reduction halos. Coarse-grained portions contain abundant muscovite, and basal gravel lags consist of clasts of quartz, bluish-gray quartz crystal tuff, and mudstone rip-ups. Extended into Moncure from Cokesbury Quadrangle. Unit may correlate with portions of the Pekin Formation. Trp - Pekin Formation: gray, Brown to maroon, white mica bearing, interbedded mudstones, siltstones arkosic sandstones and locally conglomerates. Outcrops and boulders of float identified as part of Pekin Formation are strongly indurated compared to sediments identified as part of the Durham sub-basin. Identified as the Pekin Formation by Reinemund (1955). Trpc - Conglomerate of the Pekin Formation: reddish-brown to dark brown to purplish-red, irregularly bedded, poorly sorted, cobble to boulder conglomerate. Clasts are chiefly miscellaneous felsic and intermediate metavolcanic rocks and quartz. Typically present adjacent to border faults. Outcrops and boulders of float identified as part of Pekin Formation are strongly indurated compared to conglomerates identified as part of _2 qqq> _ Durham sub-basin. Identified as the Pekin Formation-basal conglomerate by Reinemund (1955). Metavolcanic and Metavolcaniclastic Units Aaron Formation 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 west of the map area. Harris (1984) interpreted the Aaron Formation to have been deposited by turbidity currents in a retrogradational submarine fan setting. Hyco Formation - Upper Portion Zhime/pl - Mixed intermediate to mafic epiclastic-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 61 5.7+3.7/-1 .9 Ma U-Pb zircon date for a dacitic tuff from the unit in the Rougemont quadrangle. Easternmost Carolina Terrane Metaintrusive Units CZbg - Meta-granitoid rocks of the Buckhorn Dam intrusive suite: dark-colored (CI=15-30), medium- to fine-grained, metatonalite, metagranodiorite and metagranite with variably developed foliation; composed mainly of plagioclase, quartz, epidote, microcline, biotite, and opaque minerals, with minor amounts of sericite, sphene, chlorite, and garnet. Description adapted from the Cokesbury Geologic Map. Cary Sequence- Cary Metamorphic Suite CZbr3 - Big Lake-Raven Rock schist 3: light tan to orange-brown, fine- to medium-grained, white mica schist, phyllite and gneiss. Locally preserves primary volcanic texture, either fragmental or porphyritic. Inferred to have a dacitic volcanic and/or volcaniclastic protolith. Locally includes intermediate to mafic composition rocks that have been metamorphosed to mica phyllite. Description from Cokesbury Geologic Map. Altered by the North Carolina Geological Survey for use on this map Produced by the United States Geological Survey North American Datum of 1983 (NAD83) World Geodetic System of 1984 (WGS84). Projection and 1 000-meter grid:Universal Transverse Mercator, Zone 17S 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, June 2016 - November 2016 Roads . U.S. Census Bureau, 2016 Names . GNIS, 1980 - 2018 Hydrography . National Hydrography Dataset, 1899 - 2018 Contours . National Elevation Dataset, 2008 Boundaries . Multiple sources; see metadata file 2017 - 2018 Wetlands . FWS National Wetlands Inventory 1983 MN GN 0.5 SCALE 1:24 000 0 KILOMETERS ROAD CLASSIFICATION 9"1 160 MILS 1000 500 Г8 20 MILS 0.5 METERS 0 1000 2000 Expressway Secondary Hwy Ramp Local Connector Local Road 4WD 1000 1000 2000 3000 MILES 4000 5000 I Interstate Route 6000 7000 i - 8000 9000 10000 QUADRANGLE LOCATION a US Route О State Route UTM GRID AND 2019 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET U.S National Grid 100.000 -m Snuare ID PV FEET CONTOUR INTERVAL 10 FEET NORTH AMERICAN VERTICAL DATUM OF 1988 This map was produced to conform with the National Geospatial Program US Topo Product Standard, 2011. A metadata file associated with this product is draft version 0.6.18 1 2 3 4 5 6 7 8 Gf«d Zone Designation 17S 1 Pittsboro 2 Merry Oaks 3 New Hill 4 Colon 5 Cokesbury 6 Sanford 7 Broadway 8 Mamers MONCURE, NC ADJOINING QUADRANGLES Equal Area Schmidt Net Projections and Rose Diagram Plots and calculations created using Stereonet v. 10.2.0 based on Allmendinger et al. (2013) and Cardozo and Allmendinger (2013) Equal Area Schmidt Net Projection of Contoured Poles to Foliation and Cleavage in Carolina Terrane Rocks (Blue circles), N=16; and Easternmost Carolina Terrane Rocks (Triangle squares), N=34. Equal Area Schmidt Net Projection of Contoured Poles to Primary Bedding and Layering in Triassic Sediments Contour Interval =2 sigma; N=96 Unidirectional Rose Diagram of Joints N=172 Outer Circle = 10% Mean vector = 354.2° North Carolina Geological Survey Open File Report 2021-01 EXPLANATION OF MAP SYMBOLS CONTACTS, FAULTS, AND OTHER FEATURES , , inferred brittle fault, inferred contact, dotted where concealed - dotted where concealed inferred diabase, dotted where concealed _ T Jonesboro fault, dotted where concealed; ball and bar on downthrown block inferred diabase intruded along fault, dotted where concealed conglomerate beds within Pekin - * and Sanford Formations (Reinemund, 1955) - surficial units contact A' cross section line coal bed within Cumnock Formation, — * - ~ - dotted where concealed (Reinemund, 1955) IN CROSS SECTION - - contact fault, queried where questionable diabase dike, inferred foliation form lines in Easternmost Carolina terrane PLANAR AND LINEAR FEATURES [■ 81 strike and dip of bedding or layering |-84 1 strike and dip of bedding or layering 1 r74 (multiple observations at one location) 15 Triassic layering (multiple observations at one location) ^ horizontal Triassic bedding (from USGS PP 246) JS strike and dip of Triassic bedding (from USGS PP 246) [ 46 strike and dip of foliation Г 45 1 strike and dip of foliation ' ^5» (multiple observations at one location) ■f strike of vertical foliation 62 strike and dip of cleavage \84 diabase dike trend 82 diabase dike trend (multiple observations at one location) |- 87 fault plane [eo strike and dip of inclined joint л | strike and dip of inclined joint surface 68 (multiple observations at one location) Hi | strike of vertical joint quartz vein 64 (multiple observations at one location) | mineral lineation 10 (j) crenulation lineation PROSPECTS, QUARRIES AND OTHER FEATURES © observation station location • diabase station location ▼ location of chert debris >|< microfossil locality (Heckert et al., 2012) soil boring, NC DEQ Site ID NCD049845548 (S&ME Report, 1983) CGS 1977 field trip stop X clay pit - brick clay, active X clay pit - brick clay, abandoned -X- quarry - crushed stone, active X coal pit - abandoned (Reinemund, 1 955) groundwater monitoring well location Ф with bedrock data, Cape Fear Steam Electric Plant (SynTerra, 2015) a oil and gas test well CH-C-02-81 u, surficial geology station ^ location - Grimley References: Allmendinger, R. W., Cardozo, N. C., and Fisher, D., 2013, Structural Geology Algorithms: Vectors and Tensors: Cambridge, England, Cambridge University Press, 289 pp. 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., Rice, A.K., Grimley, D.A. and Blocher, W.B., 2020, Geologic map of the Colon 7.5-Minute Quadrangle, Chatham and Lee counties, North Carolina: North Carolina Geological Survey Open-file Report 2020-04, scale 1:24,000, in color. Butler, J.R., Clark, T.W. and Gay, N.K., 2016, Geologic map of the Cokesbury 7.5-minute quadrangle, Wake, Chatham, Harnett and Lee counties, North Carolina: North Carolina Geological Survey Open-file Report 2016-22, scale 1:24,000. Campbell, M.R., and Kimball, K.W., 1923, The Deep River coal field of North Carolina: North Carolina Geological and Economic Survey Bulletin 33, 95 p. Cardozo, N., and Allmendinger, R. W., 2013, Spherical projections with OSXStereonet: Computers and Geosciences, v. 51, no. 0, p. 193 - 205, doi: 10.1016/j.cageo.2012.07.021 Clark, T.W., Gore, P.J., and Watson, M.E., 2001, Depositional and structural framework of the Deep River Triassic basin, North Carolina, in Hoffman, C.W., ed. Field Trip Guidebook for the 50th Annual Meeting of the Southeastern Section, Geological Society of America, Raleigh, North Carolina, p. 27-50. (re-printed in Carolina Geological Society Field Trip Guidebook 2011) Farrar, S.S., 1985, Stratigraphy of the northeastern North Carolina Piedmont: Southeastern Geology, v. 25, no. 3, p. 159-183. 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 . Goldberg, S. A., 1994, U-Pb geochronology of volcanogenic terranes of the eastern North Carolina Piedmont: preliminary results, in Stoddard, E.F. and Blake, D. E., eds., Geology and Field Trip Guide, Western Flank of the Raleigh metamorphic belt, North Carolina, Raleigh, North Carolina Geological Survey, Carolina Geological Society Guidebook for 1994, p. 13-17. 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. Heckert, Andrew B., Mitchell, Jonathan S., Schneider, Vincent P. and Olsen, Paul E., 2012, Diverse New Microvertebrate Assemblage from the Upper Triassic Cumnock Formation, Sanford Subbasin, North Carolina, USA, Journal of Paleontology 2012; 86 (2): 368-390. doi: https://doi.Org/10.1666/11-098.1 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-2096A. 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. Hoffman, C.W., and Gallagher, P.E., 1989, Geology of the Southeast and Southwest Durham 7.5 minute quadrangles, North Carolina: North Carolina Geological Survey Bulletin 92, 34 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, 252 p. Mills, H.H., 2000, Apparent increasing rates of stream incision in the eastern United States during the late Cenozoic. Geology, v. 28; no. 10; p. 955-957. North Carolina Geological Survey (NCGS), 1985, Geologic Map of North Carolina: Raleigh, North Carolina Department of Natural Resources and Community Development, Geological Survey Section, scale 1:500,000, in color. Parker, J.M., 1979, Geology and mineral resources of Wake County: North Carolina Geological Survey Bulletin 86, 122 p., 1:1 00,000-scale map. 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. Reid, Jeffrey C., Taylor, Kenneth B., and Cumberbatch, N.S., 2010, Digital compilation map Sanford sub-basin, Deep River basin, parts of Lee, Chatham and Moore Counties, North Carolina [Seismic lines, drill hole locations, geologic units (from Reinemund, 1955), hydrocarbon shows (gas, oil asphaltic - or combination), and %Ro in wells -Area within dotted line inferred extent of %Ro 2 0.8]: North Carolina Geological Survey, Open-file report 2010-07. Reid, Jeffrey C. and Taylor, Kenneth B., with contributions by Olsen, Paul E., and Patterson, III, O.F., 2011, “Natural Gas Potential of the Sanford sub-basin, Deep River basin, North Carolina,” 57p., in Taylor, Kenneth B. and Jeffrey C. Reid, editors, "Field Trip Guidebook - 60th Annual Meeting," Southeastern Section, Geological Society of America, Wilmington, North Carolina, March 2011. Note: updated and revised version of this field trip guidebook was prepared for the 2011 annual meeting of the Eastern Section, AAPG and is available as AAPG Search and Discovery Article #10366 at URL http://www.searchanddiscovery.com/ documents/201 1 /1 0366reid/ndx_reid .pdf . Reid, Jeffrey C.; Milici, Robert C., and Coleman, James L., Jr., 2018, Mesozoic rift basins - Onshore North Carolina and south- central Virginia, U.S.A.: Deep River and Dan River total petroleum systems (TPS) and assessment units (AU) for continuous gas accumulation, and the Cumberland-Marlboro ‘basin', North Carolina: North Carolina Geological Survey, Special Publication 12, 24p. -Link to publication: https://www.nc-maps.com/ncsppu910and.html Reinemund, J.A., 1955, Geology of the Deep River coal field, North Carolina: U.S. Geol. Survey Prof. Paper 246, 159 p. Rice, A.K., Bradley, P.J., Grimley, D.A., and W.B. Blocher, 2020, Geologic Map of the Goldston 7.5-Minute Quadrangle, Chatham, Lee and Moore Counties, North Carolina, North Carolina Geological Survey Open File Report 2020-06. 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. S and ME, 1983, Geotechnical Investigation Report, Solid Waste Landfill, Moncure, NC, from the NCDEQ files of Reichhold Chemical Superfund site (NC DEQ Site ID NCD049845548), figure 3. Soil Survey Staff, 2019, Natural Resources Conservation Service, United States Department of Agriculture. Soil Survey Geographic (SSURGO) Database for Chatham, Lee, and Moore Counties, North Carolina. Available online. Accessed December 2019. Smoot, J.P., Froelich, A.J., and Luttrell, G.W., 1988, Uniform symbols for the Newark Supergroup, in Froelich, A.J., and Robinson, G.R., Jr., eds., Studies of the early Mesozoic basins of the eastern United States, US Geological Survey Professional Paper 1776, p. 1-6. Suther, B.E., Leigh D.S., and G.A. Brook, 2011. Fluvial terraces of the Little River Valley, Atlantic Coastal Plain, North Carolina. Southeastern Geology, v. 48, no. 2, p. 73-93. SynTerra, 2015, Comprehensive Site Assessment Report - Cape Fear Steam Electric Plant, pages 1010. Accessed from NC Department of Environmental Quality, Division of Water Resources online document library in 2020. 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. A Trpc Zhime/pl Qal, Qth and Qtl undifferentiated Qal. Qth and Qtl undifferentiated 300' -0’ - -2,000’ no vertical exaggeration for bedrock units Qal and surficial thickness exaggerated to be visible Department of Environmental Quality Geologic Map of the Moncure 7.5-Minute Quadrangle, Lee and Chatham Counties, North Carolina By Philip J. Bradley, Aaron K. Rice and David A. Grimley Geologic data collected in June 2020 through May 2021 Map preparation, digital cartography and editing by Philip J. Bradley, Michael A. Medina and Aaron K. Rice 2021 Moncure base map information: Base map is from USGS 2010 GeoPDF of the Moncure 7.5- minute quadrangle. Air 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). 2010 Magnetic North Declination at Center of Sheet = 9 degrees 1 minutec West This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program under StateMap award number G20AC00249, 2020. 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. Acknowledgments: This work was supported in part by the Illinois State Geological Survey, University of Illinois (with contributions to terrace and alluvium mapping by David A. Grimley). Thanks to Colby W. Brown, North Carolina Geological Survey, for field and laboratory assistance. by car Geologic Map of the Moncure7. 5-Minute Quadrangle, Lee and Chatham Counties, North Carolina