- Title
- Geologic map of the southeastern quadrant of the Warrenton 7.5-minute quadrangle, Warren County, North Carolina
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- Date
- 2017
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- Creator
- ["Blake, David E., 1960-"]
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- Place
- ["Warren County, North Carolina, United States","North Carolina, United States"]
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- Series
- Open file report (North Carolina. Geological Survey Section) ; 2017-09.
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Geologic map of the southeastern quadrant of the Warrenton 7.5-minute quadrangle, Warren County, North Carolina
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Mesoproterozoic-Paleozoic Paleozoic Mesozoic Quaternary
NorthCarolinaDepartmentofEnvironmentalQuality Thisgeologicmapwasfundedinpartbythe USGSNationalCooperative GeologicMappingProgram NorthCarolinaGeologicalSurveyPolicyandInnovationGroup OpenFileReport2017-09
MaryPennyKeley,SeniorAdvisor-PolicyandInnovation INTRODUCTION 7807'30"
3630'00"
KennethB.Taylor,StateGeologist The Warenton1:24,000Quadrangle liesinthe northeasternNorthCarolinaPiedmontentirelywithinruralWarenCounty.Itislocated75km northeastof 7815'00" Raleighinthe Henderson1:100,000sheetbetweenthe I-85andI-95urbancoridors.FishingCreek,the largesttributarytothe TarRiver,PossumquarterCreek, 3630'00" andthe upperreachesofReedyCreekincise the southeasternportionofthe quadrangle,crossingitfromnorthwesttosoutheast.The countyseatofWarenton occupiesthe highgroundnorthandwestofFishingandPossumquarterCreeks,respectively.N aturalexposuresofcrystaline rocksoccuralmostexclusively
CORRELATION alongthese drainagesandtheirnumerousunnamedtributaries.The higherareasabove drainage dividesconstitute broadgeneralyflatsurfacescommonlyOFMAPUNITS underlainbyunconsolidatedCenozoicsedimentarydeposits.The regionbetweenunincorporatedcrossroadscommunitiesofSnow HilandWarenPlainsjust EXPLANATIONOFMAPSYMBOLS
Qal northwestofWarentonandsoutheastofNorlinaisthe topographicalyhighestportionofthe southeasternWarentonquadrangle andisunderlainbylatePaleozoicgranite aswelasCenozoicdeposits.Elevationsinthe maparearange from approximately450feetabove sealevelinthe areaaround the CONTACTSintersectionofU.S.158andWarenPlainsRoad,tolessthan250feetalongPossumquarterCreekatthe southeasterncornerofthe quadrangle.U.S.Highway401andBusinessU.S.Highway158extendnorth-southandeast-west,respectively,acrossthe quadrangle andmeetindowntownWarenton.U.S.401andU.S.158continue northwestfromWarentontoNorlina.U.S.401continuessouthwestofWarentontothe countyseatofLouisburginFranklinCounty,whileNC contact diabase 58startsinWarentonandcontinuessoutheasttothe countyseatofN ashvileinN ashCounty.
Jd
concealed
diabase concealedPzCbq GEOLOGICFRAMEWORK
Ageuncertain APre-Mesozoiccrystaline rocksofthe southeasternWarentonQuadrangle are interpretedtolie withinthe Raleighte rane orbe partsofthe Pennsylvanian-A' PzCsc
PermianWise granitepluton.The easternportionandperhapsmuchofthe Raleighterane isoverprintedbythe latePaleozoicandAleghanianorogenyMacon crosssectionPPgw
faultzone (Farar,1985b;Sacks,1999;Morow,2015).Itisanortheast-southwest-oriented,dextralcrystal-plasticandpotentialynormalbrittle strandofthe easternPiedmontfaultsystem(EPFS)ineasternN orthCarolina.The Maconfaultzone separatesthe lithotectonicRaleighandSpringHope te ranes(Hatcheret al.1977;Bobyarchick,1981;Sacks,1999).Inthe WarentonQuadrangle,some Raleighte rane metamorphicrocksare interpreted tobe eitherphylonitic metasedimentaryorhighlytransposedandmylonitictoultramyloniticmeta-igneousrocksthatachievedthe garnet-silimanite zone ofthe amphibolite facies
RaleighTe rane duringmiddle tolate Paleozoictectonothermalactivity.Manyexposuresalsorecordachlorite zone ofthe greenschistfaciesretrograde overprint,likelylate metamorphosedsedimentaryandigneous Paleozoicintiming.Inotherlocalities,protomyloniticmeta-igneousrocksrecordlowertemperature dynamicrecrystalization,sericitization and/or rocks(stratigraphicrelationsuncertain) saussuritizationoffeldspars,andminortopotaxialreplacementofbiotitebychloritezone,orlittleevidence ofdynamicrecrystalizationsuggestingayoungerage.
Unmetamorphosedgranite ofthe Wise plutonunderliesthe northwesternportionofthe mapped area.Post-PaleozoicJurassicdiabase dikesare also unmetamorphosedandgeneralyorientednorthwest-southeastastheycrosscutRaleighte rane metamorphicrocksandgranite ofthe Wise pluton.
PzZlgg PzZptd PzZts Inseveralpaleogeographicandlithotectonicreconstructionsofthe southernAppalachianorogenandthe easternPiedmontphysiographicprovince,the Raleigh STRUCTURALSYMBOLSte rane,whichunderliesapproximatelyone halfofthe southeasternWarentonQuadrangle,isgroupedwiththe 633-528MaCaroliniasuperte rane (Stoddardet al.,1991;Hibbardetal.,2002,2006;Blake etal.,2012).Caroliniaisone ofseveralexotic,first-orderperi-Gondwananrealm andcircum-Atlanticisland-arc Observationsitesarecenteredonthe strikebarorareatthe intersectionpointofmultiplesymbols.
PzYmbs PzYmbsg PzYpg systemsthatwere amalgamatedtoeasternLaurentiaduringmid-Paleozoicarc-continentcolision.Itisasecond-orderlithotectonicdomainthatwasdissected Planarfeaturesymbolsmaybe cominedwithlinearfeatures. intothird-orderteranesbythe EPFS duringLaurentian-Gondwanancontinent-continentcolisioninthe latePaleozoic.The lithotectonicteranesdifferintheir proportionsofmagmaticandvolcanogenicsedimentaryrocks,environmentsofformation,majorand trace element,isotopicandzirconU-Pbgeochemical signatures,andcrustallevelsoftectonothermaloverprinting.Boththe EPFS andthe teranesare nowexposedacrossthe Wake-Warenantiform,aregional-58 strikeanddipoffoliation 65 strikeanddipoffractureorjointset scale foliationarchinthe easternPiedmont.Caroliniasuprastructuralteranesremainedatupper-crustallevelsduringAleghanianorogenesis,recording 86 (multipleobservationsatone location)greenschistfaciesmetamorphism.Infrastructuralte ranes,includingthe Raleighte rane,reachedmid-crustallevelsandwere subjectedtomiddle toupper amphibolite faciesmetamorphism.Incontrast,Farar(1985a,1985b;FararandOwens,2001;Hatcher,2010)maintainthatthe Raleighte rane isrelatedtothe 70 strikeanddipoffoliationMesoproterozoicGoochlandte rane inVirginiawhere Owensetal.(2010)obtained1.1Gaand385MazirconU-Pbagesonthe State Farm andMaidens 86 (multipleobservationsatone location) trikeo t f ntGneisses,respectively.These teranesare interpretedtohave aLaurentianratherthanperi-Gondwananaffinityeastofthe continent-islandarcsuture zone s fvericalractureorjoiset
(multipleobservationsatone location)(Hughesetal.,2014).
strikeofverticalfoliationRecently,however,the second-orderCaroliniaaffinityofthe Raleighterane hascome underquestionbaseduponnew mappingandzirconU-Pbanalyses. (multipleobservationsatone location) 62 strikeanddipofcompositionallayeringPeachetal.(2017)reportnew LA-ICP-MS U-Pbmagmaticanddetritalzirconagesforthree mappedlocalitiesofamphibolite faciesschistandgneissfrom the northernRaleigh terane inthe Middleburg,Afton,andLittletonQuadrangles.The informalSoulCityamphibolite gneissfrom the easternportionoftheMiddleburgQuadrangle yielded60agesfrom 2.9Ga�336Ma,arangedinthree clustersca.2.0�1.1Ga,1.6�1.3Ga,and1.2�1.1Ga.The maximum 65 strikeanddipofcrenulationcleavagedepositionalage forthe detritalzircongrainscanbe interpretedasca.1.1Ga.The 336Maagesmaybe relatedtoPennsylvanian-Permianage granticmicro-78 strikeanddipoffaultplanedikingfrom the Wise pluton.Inthe easternportionofthe AftonQuadrangle,the informalParktowngneissisinterpretedtobe meta-igneousbasedonaunimodal agedistributionof35zircongrains.The weightedmeanageis410.5�3.7Macorespondingwiththe EarlyDevonianperiod.Anagerangeof1.8Ga�410Ma 25 strikeanddipofspacedcleavageseparatedintotwoclustersca.650�540Maand465�410Maandamaximumdepositionalage ofca.410Mainthe EarlyDevonianperiodcharacterize the (multipleobservationsatone location) 55 strikeanddipofaxialsurface offoldLittletonschistinthe westernportionofthe LittletonQuadrangle.
The restrictionofdetritalzirconagesto2.0�1.0GaandaMesoproterozoicdepositionalage inthe SoulCityamphibolitegneisssuggestsadifference in 49 strikeanddipofshearfoliation strikeofverticalaxialsurface offoldprovenance comparedtootherRaleighte rane samples.The gneissprotolithmaybe afragmentofGoochlandte rane orperhapsanotherperi-Laurentianor peri-Gondwananlithotectonicdomaindisplacedalongthe dextralcrystal-plasticN utbushCreek-Lake Gordonfaultzone (Peachetal.,2017).The Parktown
EqualAreaSchmidtNetProjections gneissandLittletonschisthave ayoungestage andcoevalmode at415�410Maandanage spreadfrom450-350Ma,similartoothermeta-igneousrocksin trikeofverticalshearfolition 26
sa and Rose Diagram the southernAppalachianorogenwithinandbeyondCarolinia.The ca.2.0�1.0Gaand650�540Maagesinthe Littletonschistare alsoproposed tobe bearingandplungeofminerallineation PlotsandcalculationscreaedusingStereonetv.8.60basedon consistentwithbothmagmaticsourcesandsedimentaryrecyclingofzircongrainsintoasyn-topost-EarlyDevonianRaleighterane depositionalbasinhavinga .(2013)andCardozoandAlmendinger(2013) regionalsource areainCaroliniaorperhapsotherperi-Gondwanandomains.The resultsofPeachetal.(2017)suggestthatportionsofthe easternPiedmont 53 srikeanddipofshearfoliation
Almendingeretal t . t 33
mappedasasingle Carolinia-relatedRaleigh terane mayinfactrepresentdifferentstructuralblocksthathave distinctandseparable Laurentianversus 61 (multipleobservationsatone location) bearingandplungeofslickenline lineationGondwanandomainalaffinities.
12
Newmappinginthe Raleighterane hasalsoyieldeddataontwoandpossiblythree deformationeventsassociatedwiththe amphibolitefaciesmetamorphism. strikeofverticalshearfoliation
t t heas-f a t t S t (mul i t bearingandplungeo tionli i
Norhwes-orsout tplungingF1oldsandS1folitionoverprinmesoscaletransposedcomposiionallayers,0,bu arerarelyobserved.Morecommonly, tipleobservatonsatone locaion) fcrenula neaton northwest-to-southeast-plungingtighttoisoclinalfoldsoverprintcompostionallayering,S0,andhave the dominantregionalfoliation,S2,astheiraxialsurface.It Norlina 23isnotclearifthisfoliationisaregionaldextralphyloniticordextralmyloniticoverprintassociatedwiththe AleghanianorogenyMaconfaultzone orapriormid�to-latePaleozoicdeformation.Astretchinglineationiscommonlyorientedsubparaleltothe F2foldhinges.The S2regionalphyloniticormyloniticfoliationis strikeofverticaldiketrend bearingandplungeoffoldhinge refoldedbygeneralynorth-northeasttosouth-southwestplunging,uprighttoeast-vergenttighttochevrontoopenF3folds.Lithologiccorelationsandmagmatic anddetritalzirconU-Pbanalysesthatmaybe abletoelucidate the timingofstructuraleventsandcontrastingtectonicmodelsawaitfuturegeologicmapping.
88 strikeanddipoffractureorjointset observationstationlocationPREVIOUS G EOLOGICMAPPIN G
Priorgeologicinvestigationspertinenttothe southeasternWarentonQuadrangle include severalregionalandreconnaissance studies.Parker(1968)defined ical mithe structuralframeworkofthe NorthCarolinaEasternPiedmont.Amulti-countymapbyMcDaniel(1980)includesWarenCountyatthe 1:100,000scale.Farar strikeofvert fractureorjointset ne (1985a,1985b)mapped the entire easternPiedmontofNorthCarolina,definedmapunits,andproposedaregionalstratigraphyand tectonicmodel.The1:24,000-scalemapssuroundingthe southeasternWarentonQuadrangleinclude afour-quadrangleareabyStoddardandothers(2009)inthe GoldSandandCentervile Quadranglestothe southofWarentoninthe RaleighandSpringHope teranes.PeachandBlake(2016)have mappedthe easternportionofthe PPgwAftonQuadrangle inthe Raleighte rane directlysouthofWarenton.The Inez,Holister,andLittletonQuadrangles(Boltin,1985;Sacksandothers,201; 88Stoddardetal.,201;Morow,2015;Morowetal.,2016)lie tothe eastandnortheastofWarentonandalsoinclude exposuresofthe RaleighandSpringHope 72te ranesalongthe MaconandHolisterfaultzones.MappingbySacks(1996a,1996b,1996c)include lithologiesofthe Raleighte rane tothe northandnortheast 88ofWarentonaswelinthe Bracey,SouthHilSE,andGasburgQuadrangles.Bufordetal.(2007)mappedthe westernportionofthe Raleighterane alongthe PzYpg 70 87N utbushCreek-LakeG ordonfaultzone inthe MiddleburgQuadranglejusttothe westofWarenton. 56 PzYpg 47 21 82 70
88 7
62 PzYmbs 33 86 REFEREN CESDESCRIPTIONOFMAPUNITS PPgw 88 PzYmbs23 2865 PzZlgg
EqualAreaSchmidtN etProjectionof Almendinger,R.W.,Cardozo,N.C.,and Fisher,D.,2013,StructuralG eologyAlgorithms:Lineations(redtriangles)andContoured The pre-Mesozoiccrystaline rocksofthe southeasternportionofthe Warenton1:24,000Quadrangleappeartobe unitswithinthe Raleighterane orgraniteof VectorsandTensors:Cambridge,England,CambridgeUniversityPress,289pp.
PolestoFoliation(blackcircles) the Wise pluton.The latePaleozoicandAleghanianorogenyMaconfaultzone separatingthe Raleighterane from the SpringHope terane toitseast(Farar, Blake,D.E.,Stoddard,E.F.,Bradley,P.J.,and Clark,T.W.,2012,N eoproterozoictoMesozoicCon 1985b;Sacks,1999;Morow,2015)mayoverprintthe Raleighterane here.Whilesubjectedtoavariableregionalmetamorphicoverprint,mostcrystaline schist petrologicandductile-brittle structuralrelationshipsalongthe AleghanianNutbushCreekfaulttourInterval=2sigma andgneisshave experiencedsome degree ofdynamicrecrystalizationandlocalydisplayfracture,foliation,andlineationinprotomylonitetoultramyloniteand PPgw zone andDeepRiverTriassicbasininNorthCarolina,inEppes,M.C.,andBartholomew,M.J.,
nea
Nfoliations=219;Nli tions=41 phylonite.Localoutcropsofhighlyslicifiedorslicified-epidotizedcataclasiterockhave unclearprotolithaffinity.Some localitiespreserve relictplutonicand lain:FieldExcursionsipossiblysedimentarytextures,whichwhencombinedwithbulkmineralassemblagesprovide criteriaforpotentialprotolithidentification.The classificationof eds.,From the Blue Ridge tothe CoastalP nthe SoutheasternUnited
States:GSAFieldGuide 29,p.219�261.igneousrocksusesthe nomenclature ofthe InternationalUnionofGeologicalSciences(IUGS)subcommissiononthe systematicsofigneousrocksafterLe Bobyarchick,A.R.,1981,The EasternPiedmontfaultsystem anditsrelationshiptoAleghanianMaitre (2002).Althe Cenozoic-agedgeologicmaterialsidentfiedonthe maphave adetritalorigininvolvingmud-togravel-sizedclastsandoccuraspartof 76 88 tectonicsinthe SouthernAppalachians:JournalofGeology,v.89,p.335-347.eriaryuplandsedimendeposit ternarysreamandfloodplaindeposits. zYpg 72 86 eologyo he Holit -mit fax
Tt tsorQua t P 75 Boltin,W.R.1985,G ft ser71/2 nuequadrangle,WarenandHali 70 8083 PzYmbs counties,NorthCarolina:Metamorphictransitioninthe Easternslatebelt:[M.S.thesis],NorthSEDIMEN TARYUN ITS 82 53 PzYpg CarolinaStateUniversity,Raleigh,NorthCarolina,87p.12 PzZlgg Buford,C.L.,Stoddard,E.F.,and Blake,D.E.,2007,Geologicmapofthe Middleburg7.5-minute
Qal�alluvium:Tan-brown,unconsolidated,poorlysors.Deposited,angulartosubroundedclay,silt,sandandgravelt -tocobble sizedclasts.Clastsderived from PzYpg87 12 86 65 Quadrangle, es, na: orhCaroli eologicalQal suroundingoldermetamorphicandplutonicunit tedwithinandalongstreamdrainagesaspoinbar,naturallevee,andfloodplainsediments. 81 35 5 69 84 Vance andWarenCountiNorthCaroli Nt na G Survey
74
HYDROT UNIS 291877 28 85 72 73 PzYpg 8287 8558 PzYpg PzZlgg 4030 64 CarOpen-dozo,N.fileRepor,an t2007d Allmen -xx,scaledinger1:24,,R.W.000,incolor,2013,. SphericalprojecionswithOSXStereonet:
HERMAL T 77 t
38 63 65 PzZlgg37 12 86 ComputersandGeosciences,v.51,no.0,p.193-205,doi:10.1016/j.cageo.2012..021
67
75 07
15 87 17 60 81 Farar,S.S.,1985a,Stratigraphyofthe northeasternNorthCarolina Piedmont:Southeastern
PzCbq �bullquartz:White todarkgray,graveltobouldersizedclastsofmilkyandsmokyquartz.Outcropsrange insize fromisolatedboulderpilestolarger 63 88 PzYpg Geology,v.25,p.159-183.PzCbq hiltopexposures.Linearridgesofquartzcanbe identifiedidentfiedusingregularlyspacedoutcrops.Occurencesofsuchridgesare possiblyrelated to 87 79 Jd 53 33 Farar,S.S.,1985b,Tectonicevolutionofthe easternmostPiedmont,N orthCarolina:Geologicalmineralizationalongtensiongashesandbrittlefaults. PzYpg 69 3817 Jd SocietyofAmericaBuletin,v.96,p.362-380.
87 88 22 Farar,S.S.,and Owens,B.E.,2001,Anorth-southtransectofthe Goochland Terane and
PzCsc�silicified cataclasite:Green-graytowhite,finelycrystaline quartz+epidote rock.Localy,thismineralassemblagecompletelyreplacesthe hostrock. 77 PzYmbsg 5248
47 associatedA-type granites,Virginia-N orthCarolina,inHoffman,C.W.,ed.,FieldTripGuidebook,
PzCsc
Outcropsaregeneralymassive andhighlyfractured.Itsoccurence issuggestedtobe relatedtobrittlefaulting. 83 6761 61 63 12 50thAnnualMeeting,SoutheasternSectionofthe G eologicalSocietyofAmerica,v.50,p.75-92.
57 57 23 60 Hatcher,R.D.,Jr.,2010,The Appalachianorogen:Abriefsummary,inToloR.P.,Bartholomew,
IN TRUSIVEROCKS
68 62 18 28 51 M.J.,Hibbard,J.P.,andKarabinos,P.M.,eds.,From RodiniatoPangea.The lithotectonic PPgw 22 32 47 44 record ofthe Appalachianregion:GeologicalSocietyofAmerica Memoir206.p.1-19.doi.
Jd �diabase:Melanocratic(CIgreaterthan80),darkgraytoblack,fine tomedium aphyrictophyric,dense diabase consistingprimarilyofplagioclase,augite 55 76 71 PzYmbs 78 PzZptd 10.1130/2010.1206(01)
.
PzZptd
Jd andlocalyolivine.Maybe plagioclase phyric.Cropsouttypicalyasspheroidalyweatheredstreamandhilside bouldersandcobbles.Weatheredsurfacesare 70 79
47 30 41 10
15 Hatcher,R.D.,Jr.,Howel,D.E.,and Talwani,P.,1977,Eastern Piedmont fault system:
generalytangray,grayishorbrownishincolor.Formsverticalytosteeplydippingdikes.Reddashedlineslinkindividualstationlocationswherestreamoutcrops PzZptd 15 61 37 35 47 Speculationsonitsextent:Geology,v.5,p.636-640.orbouldersofdiabase areexposed.Reddotsindicate isolatedoutcropsorfloatoccurences. 79 28 88 PzZlgg PzZlgg Hibbard,J.P.,Stoddard,E.F.,Secor,D.T.,and Dennis,A.J.,2002,The Carolina Zone:
PzYmbsPzZlgg A' Overview ofN eoproterozoictoEarlyPaleozoicperi-G ondwanante ranesalongthe easternflank
82
PPgw�granite ofthe Wise pluton:Hololeucocratic(CI=5-7),tantopinkwhite topinkgray,phaneriticandmedium crystaline,xenomorphicequigranular 7 Warenton Qal
PzZpd ofthe southernAppalachians:EarthScience Reviews,v.57,p.299-339.
65
t
PPgw biotitegranite.The primarymineralassemblageincludesNa-plagioclase,microcline,quartz,biotite,andmore minormuscoviteandgarnet.Mostlyundeformed, PzYpg 78 82 82 PzYmbs
Hibbard,J.,vanStaal,C.,Rankin,D.W.,and Wiliams,H.H.,2006,Lithotectonicmapofthe
76
althoughlocalyaveryweakbiotite foliationmaybe preserved.Commonlyassociatedwithhololeucocratic(CIlessthan5)pegmatiticmicrocline,quartz,N a-23 58 78
85
Appalachianorogen(South),Canada-United StatesofAmerica:GeologicalSurveyofCanada
78 36
plagioclase,andmuscovite granite podsanddikesinoutcrop.N earitseasternborder,smalenclavesandlargerpendantsofamphibolite faciesschistand 53 58 46
88
Map02096A,scale1:1500000.
EqualAreaSchmidtNetProjectionofF2and gneissare entrainedwithinthe biotitegranite.Pavementoutcropsandexfoliatedstreambankoutcropsare commonnorthandsouthofFishingCreekandeast 1
PzZptd Hughes,K.S.,Hibbard,J.P.,Sauer,R.T.,and Burton,W.C.,2014,Stitchingthe western
30
F3FoldHinges(redcircles)andContoured andwestofU.S.401northwestofWarenton.Numerousboulderfieldsandcrosscuttingtensionfracturesarelocatedwithinthe biotitegranite. 7 885
PiedmontofVirginia:EarlyPaleozoictectonichistoryofthe Elisvileplutonandthe PotomacandPolestoF2andF3AxialSurfaces(blackcircles) 88 62 85 78
80 Chopawamsicte ranes:VirginiaMuseumofN aturalHistoryGuidebookN o.9forthe 44thAnnual
40
ContourInterval=2sigma METAMORPHICROCKSOFTHERALEIGHTERRANE PzYpg
55
N foldhinges=22; 88 3 74 58192212 Qal 43 15 VirginiaG eologicalConference,LouisaCounty,Virginia,33p. 7280 45 Le Maitre,R.W.,ed.,2002,IgneousRocks: AClassification and GlossaryofTerms:
Naxialsurfaces=23 Note:Orderoflistedunitsdoesnotimplyastratigraphicsequence,althoughunitsthatclearlypreserve meta-plutonictexturesandrelationshipsarelistedfirst. 22 58 36 26
80 14 PzZlgg Recommendationsofthe InternationalUnionofGeologicalSciences(IUGS)Subcommissionon 64 6562 PzZptd 1580 61 the SystematicsofIgneousRocks:Cambridge,CambridgeUniversityPress,252p.
PzZlgg�Liberiagranodiorite and granodioritic gneiss:Hololeucocratictoleucocratic(CI=5-25),lighttantograywhite brown,phaneriticmedium-to-coarse-80 30 32 25 2 PzYmbsg 73 78 McDaniel,R.D.,1980,Geologic map of RegionK:N orth Carolina Department of N aturalPzZlgg crystaline protomylonitictomyloniticbiotitemuscovitegranodioriteandlocalybiotitemuscovitegranite.Primarymineralassemblageincludesrelictphaneriticto 59 PzYpg 70 35 ResourcesandCommunityDevelopment,GeologicalSurveySection,OpenFileMapN CG S 80-2crystaloblasticmicrocline,N a-plagioclase,quartz,muscovite,biotite,andlocalygarnet.Maycontainxenomorphicprismsorbleddyepidote,alanite,monazite,
tandapatite crystals.Minoroccurencesofbiotite are topotaxialyreplacedbychlorite.Growthofchlorite �rosettes�demonstratesthe greenschistfacies 36 35 PPgw PzZtsPzZlgg Morow,R.M.IV,2015,The Maconfaultzone:Afoldeddextralshearstrandofthe eastern
2427 46 42 PzZpd Jd [scale1:100,000].
retrograde overprintofthisunit. zandporphyri hingranodiori PzYmbs 11 PzZlgg 59 88 PzZptd 40 iedmontaulsys .hesis)Wilmingt U f thCarolinaWilmingon,16p.
Compostionalylayeredribbonquart tictoporphyroclasticK-feldsparcrystalsthatrangefrom1cm tomorethan10cmoccurwit teto 60 46 955 74 36 38 65 68 39 P f t tem,(M.ST on,niversityoNor t granodiorticgneissprotomylonite thatmaytransitionintogranodioriticmylonite andultramylonite inhigh-strainzones.Muscovite andlocalyabundantbiotite 84 38 910 22 PzZptd 24 71 Morow,R.M.IV.,Stoddard,E.F.,and Blake,D.E.,2016,GeologicMapofthe Inez1:24,000
69 32 10 9 75 PzYmbs Quadrangle,WarenCounty,NorthCarolina:NorthCarolinaGeologicalSurveyOpen-fileReport
markthe penetrative myloniticfoliationthatasymmetricalywrapwingedK-feldsparporphyroclastsandconsistentlypreserve awest-side northsense offishflash A Qal 82 65 Jd 88 70 45 62 54 25 PzZptd 70 75 65 2016-12,scale1:24,000,incolor.regardlessofthe steepdipdirectionofthe shearfoliation.Recrystalizedwingsare commonlyelongate inthe directionofalocalypenetrative mineralstretch 57
616019 53 54 51 22 Owens,B.E.,Buchwaldt,R.,and Shirvell,C.R.,2010,Geochemicaland geochronological
39 tn
lineationofquartz-feldsparrodsandphyloslicate aggregates.Localy,granodioriticgneissisinterlayeredwithmesocraticandporphyroclasticplagioclase biotite
70 5070 38 30 149 67 PzYmbs 48 evidence forDevonianmagmatismrevealedinhe Maidensgneiss,Goochlandte rane,Virginia:i
onaliegneissproomylonietomylonie.hisuniappearst titthe CZmxgunioStoddardet. Sacksetal . 80 4329 32 34 32 34 P 74 68 71 P T P. tholomew,M.J.,Hibbard,JP. nos,P.M.,eds.,From Rodiniat
t t t t t T t obe corela ve o tf al(2009)and .(2011) 44 59 72 zZlgg 33 zZlgg oloR.,Bar .,andKarabi o
16 61 42 24 59 32 52 27 20 55 PzZptd Pangea:The LithotectonicRecordofthe AppalachianRegionGeologicalSocietyofAmericaPzZptd �Possumquarterbiotite tonalite,quartzdiorite,and diorite and gneiss:Chieflymesocratic(CI=25-50),brownishblacktogreenishblack,phaneritic 68 10 78 39 43 7 45 1515 50 16 262227 5845 25 52 3456 Memoir206,p.725�738.58 45 126 4965 52 25 48 53 5 Qal 2 75
PzZptd medium crystaline andcommonlywhitespottedporphyrtictoporphyroclasticplagioclase biotitetonaliteandtonalitegneissprotomylonite.Primarymineral
20 Qal 40 17 32 13 1186 29 60 Jd 8077 Parker,J.M.,I,1968,StructureofeasternmostN orthCarolinaPiedmont:SoutheasternGeology,assemblage includesrelictporphyrticplagioclase,biotitegreaterthanhornblende,quartz,sphene,apatite,andopaque minerals.Large readilyidentifiable K-PPgw 70
v.9,p.17-.
63 65
feldsparcrystalswere notobserved,butmaybe presentinthe finergrained,relictigneousmatrix.Localy,tonalite containsxenomorphic,andlocalyzoned 47 18 18 35 18 8 80 60 6087 PzZlgg 70 131
PzYmbs 60 Qal 20 11PzYmbsg '30" Peach,B.T,and Blake,D.E.,2016,GeologicMapofthe EasternPortionofthe Afton1:24Kepidote crystalsandxenoblasticandskeletalgarnetporphyroblastsupto1cm indiameter.Loweramountsofquartzandbiotite markquartzdiorite while 81 68 7807'30" Quadrangle,WarenCounty,NorthCarolina:USGSEDMAPOpen-file Reportfor2016,scale
hornblende andplagioclase dominatelocalandlesscommonexposuresofdiorite.Protomyloniticandmyloniticequivalentsofthese rocksare commonly 3622'781530"'00 26 3622 1:24,000,incolor."
observed.Awhite mica-biotite andquartzribbonshearfoliationaswelasdegree ofcrystaloblasticmatrixandplagioclase porphyroclastdevelopmentmarkthe Peach,B.T.,Blake,D.E.,and LaMaskin,T.A.,2017,Zircongeochronologyofthe Raleightransitionintohighlydeformedgneissicequivalents. Localwingedplagioclase porphyroclastsand asymmetricshearfoliationindicatewest-side north terane inthe NorthCarolinaeasternPiedmont:GeologicalSocietyofAmericaAbstractswithdisplacementsregardlessofthe steepdipdirectionofthe shearfoliation.Chlorite topotaxialyreplacesbiotite orinfilfracturesseparatingskeletalgarnet Produced by the United States Geological Survey. Programs,v.49,doi:10.130/abs/2017SE-289947.porphyroblastswhileplagioclase,especialyindiorite,maybe saussuritizedandsericitized.Growthofchlorite �rosettes�demonstratesthe greenschistfacies Altered by the North Carolina Geological Survey for use with map. Sacks,P.E.,1996a,Geologicmapofthe Bracey7.5-minute Quadrangle,MecklenburgCounty,retrograde overprintofthisunit.
Virginia,andWarenCounty,N orthCarolina:U.S.GeologicalSurveyMiscelaneousFieldStudies
PzZts�actinolite-bearingtalc schist:Whitetotannishwhitefloatcobblesandmassive tofoliatedchipsofveryfine-crystaline talcschistandsoapstone are MapMF-2285,scale1:24,000.
PzZt Sacks,P.E.,1996b,Geologicmapofthe SouthHilSE7.5-minute Quadrangle,Mecklenburgand
s
exposedbetweenPossumquarterCreekandBaltimore Roadonthe southeasternside ofWarenton.Pale greentowhite,thinactinoliteporphyroblastsare Brunswickcounties,Virginia,andWarenCounty,NorthCarolina:U.S.GeologicalSurveyprimarilyvisible microscopicalyassmalelongateprisms.The porphyroblastsare randomlydistributedinthe fine talcmatrix.The talcschistissimilartoother MiscelaneousFieldStudiesMapMF-2286,scale1:24,000.bodiesmappedwithinthe LittletonQuadrangle (Stoddardetal.,201).There talcschistoccurswithinbiotite gneiss.Contactrelationshipswithadjacentrock Sacks,P.E.,1996c,Geologicmapofthe G asburg7.5-minute quadrangle,BrunswickCounty,typeswere notreadilyobservedhere,andthe schistliesalongthe contactbetweenPossumquartertonalticgneissandMilBranchchloritewhitemicaschist Virginia,andWaren,Northampton,andHalifaxCounties,NorthCarolina:U.S.Geological
describedbelow. Survey,MiscelaneousFieldStudiesMapMF-2287,scale1:24,000.
UnidirectionalRose DiagramofJointsN =60
tic(C=-oreddishgreengrayt io-medi tne and Sacks,P. G ewoft t anPiedmon alongLakeGason,OuterCircle=1%
PzYmbs�MilBranch schist:Leucocra I2030)silvergreengrayt ograyandorange brown,fne-t um-crysali E.,1999, eologicovervi he easernAppalachi t t Meanvector=254.4��23.3 PzYmbs crystaloblasticquartzwhitemicaschist.Whitemica,likelymuscovite,inanygivensamplemaybe largerandomlyorderedtorosettesofplatesbetweenclusters NorthCarolinaandVirginia,inSacks,P.E.,ed.,Geologyofthe FalZone regionalongthe North
Carolina-Virginiastate line:CarolinaGeologicalSocietyFieldTripG uidebook,p.1-15.
Maxvalue =10%between331�and340� ofotherminerals,ordefinesrandomplatesandrosettesbetweenshearfoliationdomainsinphylonite.Fishflashtypicalyindicateswest-side northdisplacement Sacks,P.E.,W.R.Boltin,and E.F.Stoddard,2011,Bedrockgeologicmapofthe Holister7.5�inasteeplydippingfoliation.Quartzribbons,localfoxyredbiotiteplates,elongatecrystalsandaggregatesofopaque minerals,andveryminorepidotecontribute minutequadrangle,WarenandHalifaxCounties,NorthCarolina,NorthCarolina:NorthCarolinatothe shearfoliationinphylonite.Domainsofquartz-richversuswhitemica-richmineralizationappeartobe arelictcompositionallayering,althoughitisnot GeologicalSurveyOpen-fileReport201-03,scale1:24,000,incolor.clearifisapreservedprimarysedimentaryorshearlayering.Insome white mica-richdomains,silimanite prismsuptoseveralcm longaswelasfibrolitic Stoddard,E.F.,Farar,S.S.,Horton,J.W.,Jr.,Butler,J.R.,and Druhan,R.M.,1991,Thesilimanitereside inthe whitemicamatrix.Insome samples,opticalycontinuous,butdisaggregatedprismsofsilimaniteappeartobe crosscutandreplacedby EasternPiedmontinNorthCarolinainHorton,J.W.,Jr.andZulo,V.A.,editors,The Geologyofwhitemica.Smalprismaticchloritoidporphyroblastswereidentifiedinone sample.Some felsicclumpsinhighlydeformedandweatheredschistappeartobe K-the Carolinas,CarolinaGeologicalSocietyFiftiethAnniversaryvolume:Knoxvile,Universityoffeldsparandquartzleucosomes(?).Garnetporphyroblastsare localydevelopedassmalxenoblasticandsometimessievedporphyroblastsorxenoblastic Tennessee Press,p.7992skeletalorfracturedcrystalsthatlooklikelarge individualporphyroblastsatthe mesoscale.Chlorite replacesgarnetalongthese fractures.Chlorite platesalso ar,E.F -. Sprinkle I,D.P
s W.,an
topotaxialyreplace biotite andareaggregatesinthe shearfoliation.Growthofchlorite �rosettes�demonstratesthe greenschitfaciesretrograde overprintofthis Stodd d .,Fuemmeler,S.,Bechtel,R.,Clark,T. d .,2009,
Preliminarybedrockgeologicmapofthe GoldSand,Centervile,Castalia,andJustice 7.5-minute
unit.The schistcommonlyweatherstoarustyredcolordue toFe-oxide orFe-hydroxide andmaybe aconsequence ofthe breakdownofabundantchlorite,as quadrangles,Franklin,Nash,WarenandHalifaxCounties,NorthCarolina:NorthCarolinawelasbiotiteandgarnet.The protolithofthe schistasametasedimentaryormeta-igneousrockisstilnotclear,buthydrothermalmetasomatism and GeologicalSurveyOpen-fileReport2009-03,scale1:24,000,incolor.breakdownofrelictfeldsparsmaybe afactorinthe muscovite aswe lasschistdevelopment.Because ofthe Mesoproterozoicdetritalzircondatesobtainedfrom Stoddard,E.F.,Sacks,P.E.,Clark,T.W.,and Bechtel,R.,2011,Bedrockgeologicmapofthethe SoulCityamphibolticgneiss(Peachetal.,2017)andthe unclearprotolithrelationshipsinthe MilBranchschist,itiscurentlyinferedtorange from the Littleton7.5-minutequadrangle,WarenandHalifaxCounties,NorthCarolina:NorthCarolina
MesoproterozoictoPaleozoic,hence the PzYmbsunitagenotation. GeologicalSurveyOpen-fileReport201-02,scale1:24,000,incolor.
PzYmbsg �garnet-richmuscovite biotite schist:Mesocratic(CI=25-50)silverbrowntoblackbrown,fine-to-medium-crystaline tourmaline-bearinggarnetPzYmbsg whitemicabiotiteschist.The abundance ofplagioclase,biotite,garnet,and tourmaline prismsmarkthisunit.Plagioclase commonlyoccursaslarge relict RALEIGH GRANITEOFTHEWISEPLUTONGRAN ITEOFTHEWISEPLUTON
RALEIG HTERRAN E
TERRAN E
igneousphenocrystsnowporphyroclastssimilartothose inthe Possumquartertonalite.Foxyred-brownbiotite andwhite micaform ashearfoliationthatwraps
the porphyroclastsandtypicalyyieldsawest-side northsense ofdisplacementwhereobserved.Smalsegmentsandlargerribbonsofpolygonizedquartzalso Fishing MLKJr. Fishing S.MainSt. Possumquartcontribute tothe shearfoliation.Biotite andwhitemicawrapabundantrounded toelongate xenoblastictosubidioblasticgarnetporphyroblasts.Theyare A Creek Blvd. Creek (US401) NC58 Creek er A' generalyupto5mm indiameteranddistinctlypurple red.Microscopicaly,theircoresare imbeddedwithfine sieve inclusions,some orientedparaleltothe PzYpg Qal
PzYmbsg Qal Qal PzYmbs
externalfoliation.Tourmaline prismsare trigonalandblackatthe mesoscale andare zonedatthe microscale.Some prismshave inclusiontrailsorientedata 400
'
highangle tothe externalshearfoliation,andlocalybiotiteandtourmaline are includedinplagioclase.Apatiteandzirconare commonaccessoryminerals. PzZlgg 400'
'
Chloritemayimpartapale greencolorationtosome samples.Ittopotaxialyreplacesbiotiteandjoinswhitemicainthe shearfoliation.Localyitmaypartialy 0' Qal PzYmbs 0 suroundsome xenoblasticgarnet.Growthofchlorite�rosettes�demonstratesthe greenschistfaciesretrograde overprintofthisunit.The protolithofthe schistas zZlggametasedimentaryormeta-igneousrockisstilnotclear.Relictplagioclase texturessuggestthatsome ofthe unitmaybe deformedbiotitetonalite,perhaps PzYmbs P PzYmbscontaminatedwithametasedimentarycountryrocktoproduce the garnet.Because ofthe Mesoproterozoicdetritalzircondatesobtainedfrom the SoulCity PPgw PzYpg PzZlgg PzZptd PzZlggamphibolticgneissandthe unclearprotolithrelationshipsinthe garnet-richmuscovitebiotiteschistunit,itiscurentlyinferedtorangefrom the Mesoproterozoic 1500' PzYmbs PPgw PzZptd -1500'
-toPaleozoic,hence the PzYmbsgunitagenotation. PzZptd
PzYpg�Parktowngneiss:Compostionalydiverse intermediate andfelsicgneiss.Stronglylayeredmesocratic(CI=35-65)blackgreentoblackblue,fine-to-PzYpg mediumcrystaline hornblende biotitetonalitic,biotitequartzdioritic,anddioriticgneiss.Theirmineralogyincludesplagioclase,hornblende,biotite,quartz,local Jd PzYmbs PzYmbs Jd -
clinopyroxene,magnetite,andepidote.Biotiteandwhitemicaare compositionalylayeredwithcrystaloblasticquartzandplagioclase andproduce awel-3000' -3000' developedgneissositythatvariesfrom afew cm to10sofcm inthickness.Plagioclase porphyroclastsandleucosome stringersoffeldsparandquartzare commonlyinterlayeredwithmore mesocraticgneissanddefine trainsofporphyroclastsorientedparaleltothe shearfoliation.Hololeucocratictoleucocratic(CI=5-35)medium graytograywhitetotanwhite,fine-to-medium crystaline biotitegranodioritictograniticgneissinterlayersare commonaswel.Localy scale-124000noverticalexaggerationleucocraticlayerscontainsmalrelictgarnetphenocrystssuggestingaperaluminouscomposition.White mica,likelymuscovite,andbiotite contribute tothe shearfoliationthatoverprintsfelsicgneiss.Quartz-feldsparrodsandelongate feldsparporphyroclastscombine withphyloslicatestomarkamineralstretchlineation.Some pinkwhite layersare coarserquartz-feldspargraniticgneissandare commonlyopentoptygmaticalyfolded.The gneissiclayeringisstronglytransposeddue tostrongmylonitizationtoultramylonitization.Itisunclearwhetheranyofthe layershadasedimentaryorigin.Mesoproterozoicdetritalzircondatesfrom the SoulCityamphiboliticgneisstothe westofthe Parktowngneisssuggestasedimentaryprotolithforthatlayeredgneiss.However,numerouslayerspreserve relictigneousassemblagesandfeatures.The EarlyDevonianmagmaticzircondatesfrom the Parktowngneissmaysupportthe hypothesisthat atleastsome layersare plutonic(Peachetal.,2017).Due tothe unclearprotolithrelationshipsinthe Parktowngneiss,itiscurentlyinfe redtorange from theMesoproterozoictoPaleozoic,hence the PzYpgunitagenotation.
ThisisanOpenFile Map.IthasbeenreviewedinternalyforconformitywithN orthCarolinaGeologic Mapofthe SoutheasternQuadrant GeologicalSurveymappingstandardsandwiththe N orthAmericanStratigraphicCode.Further revisionsorcorectionstothisOpenFilemapmayoccur.
ofthe Warenton7.5-Minute Quadrangle,
Researchsupportedbythe U.S.GeologicalSurvey,NationalCooperative GeologicMappingProgram,underUSGS awardnumberG16AC00288.The viewsandconclusionscontainedin
WarenCounty,NorthCarolina
thisdocumentarethose ofthe authorsandshouldnotbe interpretedasnecessarilyrepresentingthe officialpolicies,eitherexpressedorimplied,ofthe U.S.Government.
N.C. ByDavidE.BlakeandPatrickC.Finnerty Thisgeologicmapwasfundedinpartbythe USGSNationalCooperative GeologicMappingProgramunderStateMapawardnumberG16AC00288.
Geology mapped under STATEMAP between January and May, 2017.
Acknowledgements:AaronRice,BrandonPeach,PhilBradley,SkipStoddard,andMarkCarterDigital representation by Michael A. Medina and Philip J. Bradley providedfieldassistance,fieldreview,andtechnicalsupportforthisStateMapproject.
2017
GeologicMapofthe SoutheasternQuadrantofthe Warenton7.5-minute Quadrangle,OpenFileReport2017-09
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