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CZbr1
CZpbg
CZslg
CZccg
CZbr1
CZbr2
CZcbp
DU
?
DU
CZbr1
CZbr1
CZbr1
CZbr2
?
?
CZbr1
CZbr1
DU
TrscTrsc
Trsc
Trsc
Trsc
Trsc
Trcs/c
Trcs/c
Trcs
?D
U
CZbr1
CZbr1
CZbr1CZbr1
Fe
Trcc
Trcs/c
Trcs/c
Trcs
Trcs
Trcsi/s
Trcsi/s
Trcs
Trcs/si2
Trcs/si2
Trcs
Trcc
Trsc
Trcs
Trcs/c Trsc
Trsc
Trcc
BONSAL - MORRISVILLE FAULT
LEESVILLEFAULT
JONE
SBOR
O FA
ULT
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Qal
Jd
Jd
JdJd
Jd
Jd
Jd
Jd
Jd
Jd
Jd
Jd
Jd
DU
Trcsc
Qal
CZrg
CZrg
CZrg
CZrg
CZrg
CZrg
CZrg
CZpbg
CZslg
CZslg
CZpbg CZpbg
CZslg
CZslg
CZslg
CZslg
CZpbg
CZpbg
CZslg
CZslg
CZpbg
CZpbgCZpbg
CZtca
CZslg
CZtca
CZtca
CZpbg
CZbr1
CZbr1
CY96-1931-2
CY96-1807
CY96-1750
CY97-2036
CY97-2074
1
2
46
68
?
AA'
A"
B
B'
3
CZrsFe
CZmd
CZrgCZpbg
QalQal
CY96-1633ACY96-1633B
WR94-835
CY96-1938B
CY96-1931-1
CZslg
35 52' 30"
78 52' 30"
35 52' 30"
78 45' 00"
35 45' 00"
78 45' 00"
35 45' 00"
78 52' 30"
Qal
DU
GEOLOGIC MAP OF THE CARY 7.5-M
INUTE QUADRANGLE, WAKE AND DURHAM COUNTIES, NORTH CAROLINA
OPEN FILE REPORT 2016-02
Contoured poles to regionalfoliation Srs (n = 309)
Contoured m ineral, aggregateand stretch lineations (n = 69)
Digital representation by Michael A. Medina
DEPARTMENT OF ENVIRONMENTAL Q UALITYKENNETH B. TAY LOR, STATE GEOLOGIST
BY DAVID E. BLAKE AND TIMOTHY W. CLARK
Base topographic m ap is digitalraster graphic im age of the Cary7.5-m inute quadrangle (1993), North Carolina State Plane
NAD 83 m eters coordinate system.
Field data plotted on m ylar copyof Cary quadrangle from 1973,photorevised 1987. Data digitizedand projected on to 1993 quadrangle.
Crabtree
Creek
Pluton
Cary Metamorphic Suite
Lithofacies
Assoc. II
Lithofacies
Assoc. III
Metaintrusive UnitCrabtre e Te rrane
CZ tca – Turke y Cre e k am phibolite: Melanocratic (CI greater than 65), dark gray-green to black -green, fine- to m edium -grained, and m oderately to well foliatedand locally lineated. Plagioclase, hornblende, biotite, chlorite, and epidote form a granoblastic to lepidioblastic m atrix in am phibolite, biotite am phibolite, andhornblende gneiss. R elict phaneritic textures and cross-cutting relationships are used to identify outcrops of m etagabbro and m etadiorite, while relict plagioclasephenocrysts are preserved in som e fine-grained am phibolite inferred to be m etabasalt. Locally contains porphyroblastic hornblende.
CZ c c g – Crabtre e Cre e k gne iss: Leucocratic (CI=5-10), greenish silver-gray, pink-gray, and tan-pink , m edium- to coarse-grained, and w ell-foliated and lineated,porphyroclastic granitic orthogneiss. Plagioclase, m icrocline, white m ica, biotite, and local tourm aline form a granoblastic and lepidioblastic m ylonitic m atrixsurrounding up to 1 cm oblate and rod-shaped porphyroclastic quartz aggregates. Q uartz shapes and w hite m ica define a penetrative, subhorizontal L>S tectonitefabric. Irregularly shaped block s and horizons of biotite am phibolite are inferred to be enclaves or transposed m afic dik es. This gneiss dom inates the easternportion of the Crabtree Creek pluton in the R aleigh W est Q uadrangle (see Blak e, 1994).
CZ br1 - Big Lake-Rave n Roc k sc hist (uppe r): W hite-gray to white-tan to white, fine- to m edium -grained, well foliated and locally lineated. R esistant outcropsare com m only w hite m ica schist, although com positional layers containing biotite and/or chlorite are preserved. Locally, outcrops contain clasts including w hiteto gray phyllite inferred to be m etam orphosed lapilli tephra or fine-grained volcanic rock s, thereby preserving relict fragm ental volcanic textures. Other outcropscontain a m ixed assem blage of rounded clasts of m afic and felsic volcanic detritus that range up to 20 cm in length, reflecting a volcaniclastic protolith prior tom etam orphism. Fe polygons indicate areas that contain float of iron-oxide rock . Local patches of ironstone float occur in hilltops surrounding Big Lak e inU m stead State Park .
CZ slg – Sycam ore Lake gre e nstone m etad iorite and m eta-m ic rod iorite: Mesocratic (CI greater than 50), variably light green, gray-green, and dark black -green, fine- to m edium-grained rock s containing chlorite, epidote, albite, w hite m ica, and m inor biotite. H as a crystalloblastic m atrix that locally contains relictporphyritic plagioclase and porphyroblastic actinolite in greenstone. Equigranular, finely phaneritic, sausseritized plagioclase, and block y actinolite define them icrodiorite. W here foliated, form s white m ica chlorite phyllite, phyllonite, or schist, and display a dip-parallel lineation of chlorite-w hite-m ica-quartz m ineralaggregates or vein fibers. Form s enclaves in the R eedy Creek m etagranodiorite.
CZ br2 - Big Lake-Rave n Roc k sc hist (lowe r): W hite-gray to white-tan to white, fine- to m edium -grained, foliated and locally lineated. R ock ledge-lik e outcropsof w hite m ica quartzitic schist are com m on along tributaries to Sycam ore, Crabtree, and Swift Creek s. Abundant resistant, relict phenocrysts of blue quartz, albiticplagioclase, and sanidine up to 3-5 m m in diam eter are well preserved. Local dom ains of white m ica phyllite or fine-grained schist up to several cm in lengthm ay be m etam orphosed lapilli clasts or rock fragm ents. The m ode, porphyritic texture, and inferred relict clasts suggest a felsic dacitic volcanic or volcaniclasticprotolith for this lithodem e, which is m apped betw een U m stead and R aven R ock State Park s. Sycam ore Lak e greenstone and m icrodiorite form s com positionalinterlayers with the felsic schist. Local float cobbles and pebbles of iron stone occur in hilltops surrounding Big Lak e in U m stead State Park .
CZ cbp - Coles Branc h phyllite: Tan-white-orange to dark silvery gray, fine-grained, well-foliated and locally lineated rock . Mixed m afic and felsic lithodem iccom positional layering alternate am ong w hite m ica phyllite locally containing quartz and plagioclase phenocrysts, m esocratic w hite m ica-chlorite-biotite phyllite,and locally very fine-grained greenstone and chlorite phyllite. Typically, high-strain m ylonitic and/or phyllonitic fabric elem ent overprint, especially adjacent tothe Jonesboro norm al fault, obscures prim ary protolith textures and contact relationships. These rock s m ay be volcanic or volcaniclastic based upon structural andlithodem ic position w ith respect to the Big Lak e-R aven R ock schist lithodem e. Identifiable, less silicified, clasts in Triassic silicified cataclasite typically are this phyllite.
CZ rg – Re e d y Cre e k m etagranod iorite: Leucocratic (CI less than 10), light tan-gray white, bluish-gray white, or pink ish-w hite, m edium-grained, and locallycontaining porphyritic 2-4 m m blue quartz phenocrysts. Boulder fields and m assive outcrops are xenom orphic to subidiom orphic m etagranodiorite or foliated andlineated, protom ylonitic to m ylonitic granodioritic gneiss. Aggregates of white m ica, quartz, plagioclase, and orthoclase highlight the m ineral lineation. Locallycontains subidiom orphic biotite plates and isolated clots of epidote and biotite, and is white m ica-rich in gneissic layers. Contains enclaves of Sycam ore Lak egreenstone and m icrodiorite, and is crosscut by fine-grained aplitic dik es.
Trsc - silic ifie d cataclasite: tan, tan-brow n, and w hite, silicified cataclasite that is com m only hem atite stained lim orite or displays hem atite-filled fractures. Otherfractures are in filled w ith idiom orphic to xenom orphic, m assive m ilk y quartz. Angular clasts of Triassic sedim entary units and the highly silicified and relictfoliated crystalline rock s, especially the Coles Branch phyllite are com m on along the Jonesboro norm al fault zone. Som e clasts resem ble chlorite-w hite m icaphyllite or phyllonite of the Sycam ore Lak e greenstone.
Fault Roc ks
Easte rnm ost Carolina Te r rane
Trcs/si2 - sand stone with inte rbe d d e d siltstone: cyclical depositional sequences of whitish-yellow to grayish-pink to pale red, coarse- to very coarse-grained,trough cross-bedded lithic ark ose that fines upw ard through yellow to reddish-brow n, m edium- to fine-grained sandstone, to reddish-brow n, burrow ed androoted siltstone. Bioturbation is usually surrounded by greenish-blue to gray reduction halos. Coarse-grained portions contain abundant m uscovite, and basalgravel lags consist of clasts of quartz, bluish-gray quartz crystal tuff, and m udstone rip-ups.
Metaintrusive
Trcs/c - sandstone with inte rbe d d e d c onglom e rate: reddish-brow n to dark brow n, irregularly bedded, poorly sorted, coarse-grained to pebbly, m uddy lithicsandstones w ith interbedded pebble to cobble conglom erate. Muscovite is rare to absent in the m atrix. W ell-defined conglom erate beds distinguish this unit fromconglom erate basal lags of Trcs. An arbitrary cut-off of less than 50 percent conglom erate distinguishes this unit from the Trcc conglom erate facies. Conglom eratebeds are channel-shaped and scour into the underlying sandstone beds. U nit grades eastw ard into Trcc.
Trc c - c onglom e rate: reddish-brow n to dark brow n, irregularly bedded, poorly sorted, cobble to boulder conglom erate. Muscovite is rare to absent in the verycoarse-grained to gravelly m atrix. An arbitrary cut-off of greater than 50 percent conglom erate distinguishes this unit from the Trcs/c facies. Clasts are chieflym iscellaneous felsic and interm ediate m etavolcanic rock s, quartz, epidote, bluish- gray quartz crystal tuff, muscovite schist, and rare m eta-granitic m aterial.Maxim um clast diam eters are in excess of 2 m along H aleys Branch east of the R DU airport.
Trcsi/s - siltstone with inte rbe d d e d sandstone: reddish-brow n, extensively bioturbated, muscovite-bearing, siltstone interbedded w ith tan to brow n, fine- tom edium-grained, muscovite-bearing, ark osic sandstone, usually less than one m eter 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.
Trcs - inte rbe d d e d sandstone and pebbly sandstone: reddish-brow n to dark brow n, irregularly bedded to m assive, poorly to m oderately sorted, m edium - to coarse-grained, m uddy lithic ark oses, with occasional, m atrix-supported granules and pebbles or as 1-5 cm thick basal layers. Muscovite is com m on to absent. Occasionalbioturbation is usually surrounded by greenish-blue to gray reduction halos. Beds are tabular, 1-3 m eters thick , w ith good lateral continuity. U nit grades eastw ardinto Trcs/c.
Se d im e ntary UnitQ al - Q uate rnary alluvium : Tan to light gray, unconsolidated, poorly sorted and stratified deposits of angular to subrounded gravel, sand, silt, and clay in streamdrainages. Includes point bars, terraces, and natural levees along larger creek floodplains. Foliation m easurem ents represent m esoscale crystalline basem ent inlierssurrounded by alluvium too sm all to m ap separately.
Explanation
WEST
WEST
EAST
EAST
cross sections: Depth in feet below ground surface - no vertical exaggerationSCALE 1:24000
Trcsc - pebbly sandstone: reddish-brow n, pebbly, poorly sorted, coarse-grained, lithic, feldspathic sandstone; locally contains laterally discontinuous pebble andcobble trains and conglom eratic channel lags.
GEOLOGIC MAP OF THE CARY 7.5-MINUTE Q UADRANGLE, WAKE AND DURHAM COUNTIES, NORTH CAROLINA
This ge ologic m ap was fund e d in part by the USGS National Coope rative Ge ologic Mapping Program
Contoured poles to regionalshear foliation Src (n = 33)
Contoured poles to beddingin Triassic sedim ents (n = 80)
This geologic m ap w as funded in part by the U SGS NationalCooperative Geologic Mapping Program under StateMap. Geology m apped by David E. Blak e 1997 – 1998 (StateMap Award FY 1997).Geology m apped by Tim othy W . Clark 1998 – 2001.
2016
UTM GRID AND 2003 MAGNETIC NORTHDECLINATION AT CENTER OF SHEET
8 1/2151 MILS 1 17'
23 MILS
MN
GN
WHOLE ROCK GEOCHEMICAL ANALY TICAL RESULTS
Qal
CZccg
CZ rs - Re e d y Cre e k Lake sc hist: Melanocratic (CI=100), dark green to greenish-tan, m edium-grained and porphyroblastic, m oderately to well foliated actinolitechlorite talc schist. Protolith m ay be pyroxenite or peridotite associated w ith the Sycam ore Lak e m etadiorite and Turk ey Creek am phibolite.CZrs
CZbr1
CZbr2
Re fe r e nc e s:
Metavolcanic and Metase d im e ntary Units
Fe
Disclaim er:This Open-File report is prelim inary and has been review ed forconform ity with the North Carolina Geological Survey editorialstandards. Further revisions or corrections to this Open File m apm ay occur prior to its release as a NCGS Geologic Map Series.
Newark Supe rgroup, Chatham Group
Jd - d iabase: Dark green-black to gray-black , plagioclase and augite aphyric, and locally plagioclase phyric diabase that is locally olivine-bearing. W eathersto tan-gray, spheroidally rounded, dense boulders and cobbles, or punk y cobbles and pebbles that can be traced along strik e w here outcrop is not continuous.
Intrusive Unit
CZ pbg – Pots Branc h gre e nstone: Melanocratic to m esocratic (CI greater than 50), variably light green, gray-green and dark black -green, fine- to m edium-grainedrock s containing chlorite, epidote, albite and actinolite. H as a crystalloblastic m atrix that locally contains relict porphyritic plagioclase actinolite.CZpbg
CONTOUR INTERVAL 10 FEET
1 0 10.5Miles
1,000 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000500Feet
1 0 10.5Kilometers
SCALE 1:24 000
Sc hm id t Equal Area Ste re ogram Data
Blak e, D.E., 1994, Intrusive and deform ational relationships of the Crabtree Creek pluton in west R aleigh, in Stoddard, E.F. and Blak e, D.E., eds., Geology and Field Trip Guide, W estern Flank of the R aleigh Metam orphic Belt, North Carolina, R aleigh, North Carolina Geological Survey, Carolina Geological Society Guidebook for 1994, p. 25-37.Blak e, D.E., Clark , T.W ., and H eller, M.J., 2001, A tem poral view of terranes and structures in the eastern North Carolina Piedm ont, in H offm an, C.W ., ed. Field Trip Guidebook for the 50th Annual Meeting of the Southeastern Section, Geological Society of Am erica, R aleigh, North Carolina, p. 149-180.Clark , T.W ., Gore, P.J., and W atson, M.E., 2001, Depositional and structural fram ew ork of the Deep R iver Triassic basin, North Carolina, in H offm an, C.W ., ed. Field Trip Guidebook for the 50th Annual Meeting of the Southeastern Section, Geological Society of Am erica, R aleigh, North Carolina, p. 27-50.Farrar, S.S., 1985a, Stratigraphy of the northeastern North Carolina Piedm ont: Southeastern Geology, v. 25, no. 3, p. 159-183.Farrar, S.S., 1985b, Tectonic evolution of the eastern Piedm ont, North Carolina: Geological Society of Am erica Bulletin, v. 96, p. 362-380.Fortson, C.W ., 1958, Geology of the Crabtree Creek area, northw est R aleigh, North Carolina (M.S. Thesis): R aleigh, North Carolina State U niversity, 101 p.Goldberg, S.A., 1994, U -Pb Geochonology of volcanogenic terranes of the eastern North Carolina Piedm ont: Prelim inary results, in Stoddard, E.F. and Blak e, D.E., eds., Geology and Field Trip Guide, W estern Flank of the R aleigh m etam orphic belt, North Carolina, R aleigh, North Carolina pp.13-17.H ibbard, J., Stoddard, E.F., Secor, D., Jr., and Dennis, A., 2002, The Carolina Z one: Overview of Neoproterozoic to early Paleozoic peri-Gondw anan terranes along the eastern flank of the southern Appalachians: Earth Science R eview s, v. 57, n. 3/4, p. 299-339.H offm an, C.W . and Gallagher, P.E., 1989, Geology of the Southeast Durham and Southw est Durham 7.5-m inute Q uadrangles, North Carolina, Bulletin 92, North Carolina Geological Survey, 34 p.Le Maitre, R .W ., Ed., 2002, Igneous R ock s: A Classification and Glossary of Term s: R ecom m endations of the International U nion of Geological Sciences (IU GS) Subcom m ission on the System atics of Igneous R ock s: Cam bridge, Cam bridge U niversity Press, 252 p.Park er, J.M., 1979, Geology and m ineral resources of W ak e County: North Carolina Geological Survey Bulletin 86, 122 p., 1:100,000-scale m ap.Stoddard, E.F. and Blak e, D.E., eds., Geology and Field Trip Guide, W estern Flank of the R aleigh m etam orphic belt, North Carolina, R aleigh, North Carolina Geological Survey, Carolina Geological Society Guidebook for 1994, 110 p.W eem s, R .E. and Olsen, P.E., 1997, Synthesis and revision of groups within the New ark Supergroup, eastern North Am erica, Geological Society of Am erica Bulletin, v. 109, n. 2, p. 195-209.
Explanation of Map Sym bols
26
42 6
9
11
31
17
Strik e and dip of inclinedshear foliation (Src)
Bearing and plunge of m ineral stretch lineation
strik e and dip of axial surface of F4folds associated with Mesozoic faulting
Bearing and plunge of m ineral elongation lineation
Bearing and plunge of crenulation lineation
Observation sites are centered on the strik e bar or are at the intersection point of m ultiple sym bols.Planar feature sym bols m ay be com bined w ith linear features.
Strik e and dip of vertical foliation (Srs)
Strik e and dip of inclined foliation (Srs)
Strik e and dip of inclined beddingof Triassic sedim entary rock s
observation station location
Planar Features Line ar Features
Mine ral Resourc e s andOthe r Features
geochem ical sam ple location
active crushed stone quarry
abandoned building stone quarry(Sycam ore Creek quarry, Park er, 1979)
CY97-2074
1
2Cross Se ction
geologic contact
concealed geologic contact
Contacts
fault - D indicates dow nthrow n side,U indicates upthrow n side? indicates extent uncertain
Lithologic contacts - Distribution and concentrationof structural sym bols indicates degree of reliability.
DU
inferred geologic contact
?
cross section
Three discordant fractions of euhedral, colorless to light pink zirconyield 207Pb/206Pb ages of 573, 574, and 579 Ma and an upper intercept ageof 575 +- 12 Ma, interpreted as the tim e of crystallization (Goldberg, 1994).
3
42 Bearing and plunge of lineation
NORTH CAROLINA GEOLOGICAL SURVEYOPEN FILE REPORT 2016-02
Pre-Mesozoic crystalline rock s in the eastern portion of the Cary Q uadrangle represent the easternm ost exposures of the Late Proterozoic to Cam brian Carolina terrane. A sm allportion of the Late Proterozoic to Cam brian Crabtree terrane is located in the extrem e southeast corner of the quadrangle. Triassic sedim entary lithologic units of the Durham sub-basin of the Deep R iver Mesozoic rift basin underlie the w estern portion of the Cary Q uadrangle.
U ltram afic to felsic units of the easternm ost portion of the Carolina terrane (Cary sequence, Park er, 1979; Cary form ation, H ibbard et al., 2002; Farrar, 1985a) have beenm etam orphosed to the chlorite zone of the upper greenschist facies during late Paleozoic contractional tectonotherm al activity and early Mesozoic rifting. The sm all portion of theCrabtree terrane experienced am phibolite facies m etam orphism. Only Triassic sedim entary rock s, Jurassic diabase dik es and sills, and silicified cataclasite are unm etam orphosed.Although Late Proterozoic to Cam brian volcanogenic rock s w ere subjected to low-grade m etam orphism , locally undeform ed, as well as foliated and cataclastically deform edrock s of the easternm ost Carolina terrane preserve relict plutonic and volcanic igneous, as well as sedim entary textures, which allow for protolith identification. In otherexposures, partitioned high strain produces m ylonitic, ultram ylonitic, and phyllonitic rock s of variable protolith affinity.
Metaigneous rock s in both terranes are classified and nam ed using the nom enclature of the International U nion of Geological Sciences (IU GS) subcom m ission on the system aticsof igneous rock s after Le Maitre (2002). R elict igneous textures, m odal m ineral assem blages, or norm alized m ineral assem blages w hen w hole-rock geochem ical data areavailable, provide the basis for nam ing m etaigneous lithodem es. A prelim inary lithodem ic designation is developed here follow ing Articles 31-42 of the North Am ericanStratigraphic Code. These rock units, which lack geochronologic data and stratigraphic facing directions, warrant such a designation. Past m aps and lithologic descriptions ofFortson (1958), Park er (1979), and Farrar (1985a, b) in the Cary Q uadrangle assisted the developm ent of the current m apping results. Detailed descriptions of som e lithodem icunits are reported in Blak e (1994), Stoddard and Blak e (1994), and Blak e et al. (2001).
Triassic sedim entary rock s of the Cary Q uadrangle are part of the Chatham Group of the New ark Supergroup (W eem s and Olsen, 1997) and occur in the east-central portion of theDurham sub-basin, a com ponent basin of the Deep R iver Mesozoic rift basin. Detailed descriptions of Triassic sedim entary units are reported in H offm an and Gallager (1989) andClark et al. (2001). Due to the interfingering nature of these sedim ents and the lack of distinct m ark er beds, lithofacies m apping w as utilized to group the rock s into m appableunits. H offm an and Gallagher (1989) identified distinct lithofacies in the Durham sub-basin. These lithofacies were grouped in three lithofacies associations, identified asLithofacies Association I (LA I), Lithofacies Association II (LA II), and Lithofacies Association III (LA III). In general, LA I contains interbedded sandstone and siltstone and isinterpreted as braided stream deposits. LA II also contains interbedded sandstone and siltstone, but is interpreted as a m eandering fluvial system surrounded by vegetatedfloodplain. LA III contains poorly sorted sandstone, pebbly sandstone, and conglom erate. LA III is interpreted as alluvial fan com plexes characterized by broad, shallow channelsw ith high sedim ent concentrations, and locally, high-energy debris flows. LA I lithologies are not present in the m ap area.
INDEX TO GEOLOGIC MAPPING
Trcc
Trcs/c
Trcsc
Trcsi/s
Trcs/si2
Trcs
Trsc
CZrg
CZslg
CZtaCZtca
CZcbp
NORTH CAROLINA
MAP LOCATION
Jd
?brittle norm al fault - solid w here k now n,dashed w here inferred? indicates extent uncertain
diabase contact - solid w here location k now n,dashed w here inferred, dotted where concealed
fault line
lithologic contact
ductile norm al fault
diabase
0
-4000 -4000
0
-4000
00
-4000
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