Geologic map of Orange County, North Carolina

QUATERNARY MESOZOIC MESOZOI PALEOZOIC(?)C/ PALEOZOIC(?)/ NEOPROTEROZOIC NEOPCAMBRIAN(?)/ ROTEROZOIC NEOPROTEROZOIC ? MAPUNITS Qal Qcv aluvium(Qal) coluvium(Qcv) Jd diabase Trq-breccia quartzbreccia(faultrock) TriassicSedimentaryRocks DeepRiverBasin:DurhamSub-basin Trcs/si1 sandstonewithinterlayeredsiltstone oftheChathamGroupLithofaciesAssociationI MPzgb olivinegabbronorite MetamorphicRocks DikespresentinProspectHillPluton Pdad Padid daciticdikes(Pdad) andesitictodaciticdikes(Padid) ProspectHillPluton metaintrusiverocks CZtgd CZgr-gd tonaliticgranodiorite(CZtgd) graniteogranodiorite(CZgr-gd) relatedtoca.546maRoxboropluton (Wortmanetal.,200)DikepresentinFarringtonPluton CZgb gabbro(CZgb) EastandWestFaringtonPlutons metaintrusiverocks asarrnonuonmanaces(Zefg-m) asarrnonuonmainfaciesvariety1(Zefg-m1) Zefg-m Zefg-m1 Zefg-2 Zefg-3 asarrnonuonporphyrticgranite(Zefg-2) asarrnonuonfine-grainedgranite(Zefg-3) asarrnonuongraygranitoid(Zefg-4) Zefg-4 Zefg-6 Zefmd Zwfd asarrnonplutonsatellitegranitoid(Zefg-6) EastFarringtonmonzodioriteporphyryofTerrelsCreekarea(Zefmd) WestFarringtonplutondiorite(Zwfd) EastFarringtonplutonisca.579Ma(TadlockandLoewy,206) HycoFormation metaintrusiverocksassociatedwithHycoFormation:upperportion (stratigraphicrelationsuncertain) ca.613and614Ma(Wortmanetal.,200) Zgr Zgr2 Zgr-di Zgd granite(Zgr)and(Zgr2);granitetodiorite(Zgr-di);granodiorite(Zgd) Zgd-fine Zgd-leuco Zagd-fine finnee-r-graainneedgalrtaenroedigorraitneo(dZiorgdi);te(fiZnea-ggdr-afiinneed)luecocraticgranodiorite(Zgd-leuco); Zgd-gr-p granodioritetograniteofPineyMountainCreekarea(Zgd-gr-p) BuckwaterCreekPluton:granodioriteanddiorite(Zg-di-b); Zgd-di-b Zdi-gd-b porZpghdyr-itic dioriteandgranodiorite(Zdi-gd-b);porphyriticgranodiorite(Zgd-porphyritic)granodioritetogabbro(Zg-gb);tonalitetoquartzdiorite(Ztqdi); Zgd-gb Zt-qdi Zqmd quartzmonzodiorite(Zqmd)Zdi Zdi-fine Zdi-gb Zgb dgiaorbbitro(eZZdgib);)fine-graineddiorite(Zdi-fine);dioritetogabbro(Zdi-gb); Zum ultramafic(Zum) metamorphosedvolcaniclasticsedimentaryandpyroclasticrocks associatedwithHycoFormation:upperportion(stratigraphicrelationsuncertain) ca.613-616Ma(Wortmanetal.,20;Bowman,2010;andBradleyandMiler,201) Zq Zhat(u) Zmi quartzbodies(Zq);alteredtuffs(Zhat(u);porphyriticmaficintrusive(Zmi) epiclastics(Zhe);MorganCreekepiclastics(Zhe-m1andZhe-m2)mxeecasc-rocascrocs(Zhe/p); Zhe Zhe-m1 Zhe-m2 Zhe/p Zhe/p-n Zhe/p-d mxeecasc-rocascrocsoNevileCreekarea(Zhe/p-n); mxeecasc-rocascrocsofDukeQuarryarea(Zhe/p-d) Zhe/pl Zhiflt mixedepiclastic-pyroclasticrockswithinterlayereddaciticlavas(Zhe/pl); intermediatetofelsiclavasandtuffs(Zhiflt anescoasaclavasandtuffs(Zhablt);andesiticshalowintrusive(Zhasi); Zhablt Zhasi Zhabsi andesitictobasalticshalowintrusive(Zhabsi) mixedpyroclastic-epiclastics(Zhp/e);daciticlavasandtuffs(Zhdlt(u); Zhp/e Zhdlt(u) Zhdsi(u) daciticshalowintrusive(Zhdsi(u) metaintrusiverocksassociatedwithHycoFormation:lowerportion (stratigraphicrelationsuncertain) ca.630Ma(Wortmanetal.,200) Zgr-ch Zgd-ch metamorphosedvolcaniclasticsedimentaryandpyroclasticrocks associatedwithHycoFormation:lowerportion(stratigraphcrelationsuncertain) ca.629-633Ma(Wortmanetal.,20andBradleyandMiler,201) Zhat(l) Zhmst alteredtuffs(Zhat(l);matrixsupportedtuffs(Zmst)Zhft(l) Zhft-b(l) felsictuffs(Zhft(l);felsictuffsoftheBlackwoodarea(Zhft-b)Zhdlt-daciticlavasandtuffs(Zhdlt(l);altereddaciticlavasandtuffs; Zhdlt(l) Zhdlt-a(l) porph (Zhdlt-a(l);porphyriticdaciteassociatedwithZdlt(Zdlt-porph) daciticshalowintrusive(Zhdsi(l);quarzdaciteporphyry(Zhqdp); Zhdsi(l) Zhqdp Zhadlt andesitictodaciticlavasandtuffs(Zhadlt) LOCATIONOFORANGECOUNTY EqualAreaSchmitNetProjectionofContouredPoleso PrimaryLayering,BeddingandWelding/CompactionFoliation. ContourInterval=1N=804 EqualAreaSchmidtNetProjectionof ContouredPolestoFoliationandCleavage ContourInterval=1N=2,779 1-MartinMorrowpyrophylitemine-abandoned 2-unnamedprosect-abandoned 3-DelDawsonprospect-abandoned UnidirectionalRoseDiagramofJointsN=3,530 4-pyrohyliteprospect-abandone OuterCircle=4% 5-Teerpyrophyliteprospect-abandoned 6-Oakspyrophylliterospect-abandoned 7-Stroudcopperprospect-abandoned 8-pyropyliteprospect-abandoned 9-Bradsawpyrophylltemine-abanoned 0-NorthStategoldmine-abandoned -Raygolrosect-aanone 2-unnamerosect-aanone 3-unnamedprospect-abandoned 4-DukeForestgoldrospect-abandoned 5-Weaver-Carrgoldprospect-abandoned 6-NunnMountaingoldmine-abandoned 7-ChapelHilIronmine-abandone 18-LaurelHilquartzprospect-abandoned Exampleofdatadensityat 1:24,000-scalefor 1.5mile-widearea.Examplefromnortheast OrangeCountyalongNorthFork ofLitleRiverintheRougemont Quadrangle(Bradleyetal.,201). GEOLOGICMAPOFORANGECOUNT Y,NORTHCAROLINA Site-specificinvestigationsshould use1:24,000-scalemaps. ByPhilipJ.Bradley,HeatherD.Hanna,NormanK.Gay,EdwardF.Stoddard,RandyBechtel,CindyM.Philips,StephenJ.Fuemmeler MappreparationandeditingbyPhilipJ.Bradley,HeatherD.HannaandMichaelA.MedinaDigitalrepresentationbyMichaelA.Medina,PhilipJ.BradleyandHeatherD.Hanna ORANGECOUNTY 1:24,000QUADRANGLES 2016 7915'00" 7907'30" 7900'00" 3614'30" Qal Zhft(l) Qal 3614'30" Jd Qal CZtgd Zhdlt(l) Zhft(l)Padid Padid Zhdlt(l) CZgr-gd 79 Qal Zdi 6478 84 88 Jd 878684 75A Padid CZgr-gd Zdi 73 78 Qal Qal Zhdlt-porph 82 7181 76 807774Zdi Padid Zhdlt(l) Zhdlt(l) 66 Zhe/p Zhdsi(u)86 82 Zhft(l) 81 8874 Zhe/pl 84 27 Qal 82 Zhdlt(l) CZtgd CZtgd Qal 88 8382 89 76 Q87al 81 Qal CZtgd 77 7878 Zhablt 74 88 74 86 7875 Zhdl7t4(u) Zhdlt(u) Zdi 70Qal CZtgd Zhdlt(l)Qal 71 Zhdsi(l) Zhe/p 73 8479 Zhdlt(l) 86 81CZgr-gd Padid Padid Zhdlt(l) 67 81 Zhdlt(l) Zhdlt-p Qal 72 78 Zhdlt(u) 88Qal QaZlhdlt(l) Qal CZtgd Qal 72 8485 86 88 Qal Pdad Qal CZtgd 81 76Qal CZtgd 64 Zhdlt(l) Zhdlt(l) 88 81 Zhft(l) 77 8487 Qal 81 5672 85 Zhdlt(l) Qal 84 8177CZtgd Padid Qal 78 Zhe/p 76 CZtgd 72 75 Qal Qal 88 89 Qal 74 69 5762 75 Zdi Qal 8881 Zhe/plPadid Padid 84 88 Qal 63 86 Zhdlt(u)Q81al 82 Qal 88 Zhdsi(l) 8665 71 Jd 84 Qal 84 Qal CZtgd Zhft(l) Zhdlt(l) 75 8068 82Qal 79 42 85 Qal 8474 82 Zhft(l) 7714 86 84 62 Jd Qal 86 Zhablt 81 62 6586 Zhe/p 71 8674 81 Qal 72 84 Zhe/p 77 85 Q8a6l 86 Zhablt 7861 65 Zhdlt(u) 78 88 83 5459 Zhdsi(l) Zhasi 8487 82 Zhft(l) 80 Zhablt 81 59 Zhdlt(l) 79 Zhe/pl Zhft(l) 88 79 Qal 81 77 7669 82 72 87 71 84 7481 Zhdlt(l) 88 7154 Z8h7ablt Zhat(l) 7584 85 Zhablt 72 81 Q8a0l Zhablt 71 59 Jd81 7282 82 Qal 74 71 Zhablt 86 68 Zhablt 84 73 7976 7777 Zhdlt(l)8471 75 88 79 82 Jd 12 Zhablt 81 84 8884 89 83 84 Qal 8686 77 82 Zhft(l) 77 897688 86 84 Jd 76Zhft(l) 74 87 Zhft(l) 48 86 Jd 84 Qal 72 Qal 88 8Z2hdlt(l) 86 Zdi 78 Zhe/p 84 8551 Qal 74 6171 Jd 81 Jd 88 Zhdlt(l) Zhdlt(l) Jd 79 Zhe/p 71 7077 Qal 65 71 Zhasi Zhe/pl 80 75 Qal 8481 78 68 80 62 8829 72 Qal 74 Zgd-gb 78 79 Qal 82 88 Zhe/p 6264 56 76 14 Zhasi 76 Zhe/pl 85 66 Zhdsi(l) 4178 81 Jd 76 8288 19 Zhd7lt9(l) 84Zhft(l) 82 Qal 88 79 Jd 82 7078 76 Zhe/p 70 Qal 85 Zhat(l) 75 6971 Jd 75 Zgd-gb 84 77 7681 75 77 Jd 86 Zhft(l) 83 Zhdsi(l)3607'30" Jd 81 Qal 88 86 Qal 86 Zmi Zgd-gb 81 Zhft(l) Zhablt 76 Jd Qal 75 7571 Zq 3607'30" 62 637674 89 89 88 81 78 Qal Zha Zhat Zh bl Jdp 82 Q7 81 85 80 64 86 B 6 Qal 0 Zgd Zhe/b 75 Zgd-gb -g Qal Zhft(l) Zhft(l) t(l) 79 (l) 74 74 80 70 76 Qal 7Q0 al Jd 7488 60 Zhe/p 74 Zgd-gb Zhft(l)Qal 8 66 88 6 Zgd-gb Zhdlt(l) 71 l) Zhft85(l) 827 79 Z 8 q Zhablt Qal 8 88 Zhft(l) Qal Zhe/p 7 Zhft(l) 69 Zgd-gb 80 82 CZtgd Zgd-gb Qal 60 Zh Zhe Zhablt Zhe Qal 69Q Zhdlt(l) 80 Zdi a l a l 77 Z Zhabl di 80 t Zdi Qa Z Zhabl a t l hablt tQa l Zhasi 57 ablt Q77al Zmi 73 78 83 Zhdlt(u) 67 Qal 55 Z Zdi h83e/p 75 Qal Qal Zg 73 d 7Z5hdlt(l) 75 Zhdsi(l) 85 60 Zhft( 8 Zhdlt(l) 7 Zgd-gb Jd 1 Zgd-gb Zhft(l 20 Qal Qal Zhdlt84(l) Qal) 74 Zhabl 72 70 85 t 81 87 QalZ 80 ZhQ3a e l 1 88 Zhabl t 74 7Z6hdlt(u) Qal 84 6 5 Qa Zdil Zhasi Z 66 Zhat(l) 88 Z d-di po-b Zgd rphy 88 -iti Jd Zhft(l) 88 87 Qal 85 Jd Zdi Qal q Zq 6 Zdi 8 Z 67 hab g r c 82 80 24 l t Zhft(l) 83 he Qal Zhablt Jd Zhdlt(l)Ql 76 75 Zgd-gb Zgd 79 78 -fine 81 Zhft(l) 62 21 26 7 6 Z 78 he/p-d 76 Qal Zdi 76 Zhe/p-d 8 78 1 Z89hat(l) 75 Zhadlt 64 Zdi 81 5 0Qal Zq Jd Zgd-di-b Zhablt 77 BUS. 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Zgd leuco 71 -Qal Zhabl 86 a l 84 Zhat(l) Qal 76 76 70 Zhe Zhablt 70 Zhp/e 81 Qa8l4 81 9 ZhablZhdl 79 /74 78 74 p 75 Zh72e/ tt Q 86 aZ 8842 h l Z 76 hablt ZheQ/p84 Zhablp 80 t Zhablt ZhZhe ablt Zgd-fi 71 64 tZ d-l Qal Zht al h Zdi Zhdlt(l) Qal Qa (l )80 Qal 85 80 Zhat(l) 6 Qal 8 Qal Zhe/p Qal 84 Zhabl 88 t 746 6 82 Qal 73 Qal 79 Zhablt 77 74 80 74 l Zhdlt(l) Jd Qal Zhft(l) Q Zhaa t 65 Z Zhablt 71 Zhe neZd g Zgd-fi -fine Q nel gZ euco gd-leuco 84 Zhabsi gdZ Zdi ZhablZhdlt (tl) 79 abl 76 Z Qal Z (l)h Qal Zdi 85 Zhe 8/2 Zhat(l) 88 Qa l 6 25 9 88 Qal 7 Qal 71 8 Zh Jd Zhdlt(l)l mst Qa 62 Qal Zhft(l) Zgd-gr-pp t a Zhablt 78 ZdiQ a l a l 88 72 76 Z 82 h at(l) 80 (l) 67 p/e Zhabl 77 t 84 84 Zhablt 79 36 74 Zhdlt8(2u) 87 88 84 Zhablt 87 84 Z Zd 5 ha 74 80 Zh at Zhd 4 t 86 Jhdsi(u)(u7)0 (u 8) Zdl 72i 84 Zhdlt(l) Zhat(l) 4 82 Zhdlt(l) Zhabl 46 Jd 8085 Zdi Zhabl 86 t 76 t Zhabl 75 t Zqmd ZdiZh ZZ 86 d 74 Zhft(l) hat(l) Zhm abZ l 75 75 Jd Z Qal hablt tha s Zhabl t Z t ghft(l) ZhdZlth(al) t 80 Zhft(l) Zhablt (l)di t 72 Zhablt 78 79 Qal Zgd U D Qal -gr-p Jd 64 Zhe/p 88 (l)Z 84 at (l)Zd i Zhft( Zqml) d 77 Z 7 h 1 at hft(l) Qa (l) l Zdi ZQhat(l)8l 60 dlt a 8 74 Zh 84 (l)Zh 68 83 82 7481 ft-b(l) 80 85 87 Qal Qalhablt 76 Zdi 73 Zdi 58 71 Zhablt Zgb Zqmd 79 86 Zhdsi8(6u) 88 86 84 87 Zhdlt(l) 79 Zdi Zqmd Zhft-b(l) Zhdlt(l) 69 Zh 87 dlt(u)Zhablt 88 Q78a l 8 Zhe 8 86 Zdi 87 89 84 88 75 Zdi 1 54 Zhe/p 87 ZZ g84b 70 4 J 71 d Jd 64 ZdiZ Zdi Zhablt ZgdZdi Zhe/pQal Zgd-gr-p gZdh Zhe t(u ) 40 73 70 76 Z 81 hablt 81 74 Zhe 8 565 8 84 2 Zhp/e 89 Zdi 89 Zh8d4lt(l) 71 65 86 Zhadlt 80 8Q4 79 Zdi Zgad l 61 Zhe 64 Zgb 65 Zhdlt(l) Zgb ZdiZ hdlt(l) Zdi 81 Zhe 34 9 d 8 J 82 Zhablt Jd Zgd/p Zdi Z Tr Zhdlit Zdi) de 86 Zdi Zdi Zgd ZgdZ gQal cs/sZdi (u1 3600'00" Zdi-gDb U di Zhe/p 19 Jd 74 4 Zdi 76 88 82 84 76 Zh 89 p87/e 88 88 86 78 Zhdsi(u) Zhdlt(u) 8 l Q 8 a 88 88Q Zhp/e d a l Zwf Zhdsi(u) Qal 87 h Z Z Zhdsi (u) Zhp a /e b l 71 J Zhdsi(u) 89 Zhdlt8(8u) 80 Jd 88 d 86 Zhp/e Zgd t 1 0 84 87 Zhablt 78 Z8g4d Qal 77 Zhe 84 74 69 Zhe 88 86 Zdi Zgb77 Jd Zhdlt(l) 8Q4Zd Zhft-b(l) 89 67 83 Z 79 hablt Zdi Zdi 62 80 87 Zhe a i l 79 Zhe 66 Zdi Zgd 4 7/8p 8 83 Zhft(l) 77 79 78 Qal 75 88 87 1 88 6 82 89 86 1 76 86 dZh 8Q8 J 87 dl 7(8u hdlt(u)) Jd Zhat(u) 79 1Zgd d 88 69 8 J 8 Zhat( 74 86 82 u Z 80 d t ) 85 a l 80 Zdi 78 75 85 Zhe 85 78 ZwfdJ g Qa l Zwfd 85 Zhe/p Zhdlt(l) 78 75 1 85 2 Qal 74 71 82 Zhdsi(l) 32 Z78 81 Zhat(l)Zh � 85 gd Zhdlt(l)76 Z Zhe/p Zhe 64 Qal 84 Zhe/ Zgdp 75 Zdi-fine Zhe/p 15 ZdiZhe/p 72 U D Qal 63 Zdi Zgd 86 1 Zgd 6 89 Zhdlt8(1u 79 75 Zhe/p-n 81 28 e/p n 84 Qal q 18 74 Zhe/p Zdi 64 Zdi 89 Jd 22 81 Zgr2 85 70 d 74 ZwfdQal 85 Zwfd 86 /pZhablt 13 80 Z 70 Z gr Zhifl 6 gr t Zhdlt(l) 7 p Zg 74 76 84 89 Zhdlt(l) 8Z1he/p Qal 64 Zhe/p Z 81 grQ 65 Zdi 74 86 ZdiZhdl Zhe/ 79 79 Zgr2 b 77 72 Zhdlt(l) 70 ZgdJ Zum Qal (l) 17 t ZgdZh ld 76 aZ i ZZhhee//p Jpd Zgd h ) 78 Jd Jd 10 Qal Trcs/si1 Jd 12 Qal Z 26 e/p Zhe/p Qal Zhe/p Qal Trcs/si1 e/p Zhe/p d 85 75 84 Zw 78 Zhfd e/p 73 85 84 Zgd Zgr2 88 85 Zgr2 7278 74 l Qa Zhe/p 84 77 7471 80 80 Zhifl Q 82 t 68 ZdiZh Qal 6 Qal 80 69 Zwfd 5 68 a7l0 3552'30" 79 Zhabl 3 70 h qd 71 p Z at 15'00" qdp grZh Z bl 85 t 70 Z Zhiflt Zhiflt gr 7 Jd JdZ Jd hqdp ZhiflZ t efmd Zgd 85 Zgr2 q Zgr2 Zgd Zhe/p 80 Zhdlt(l) Zhe/ Qal Zhe/p Zhdlt(l) Zdi Zum Zh dp 88 Zhe/pMPzgb Z Zefmd Zefg-6h dp q 74 76 Zhe/p-n 70 Zhablt 76 Qal 75 Qal 85 Zhqdhiflt Zhiflt p Zwfd Z Zhdlt(l)d 8 Zhqd 0 78 p 80 75 Zd Zhe/i p-n 72 88 71 81 Zgd p 79 Qah h l Z Z / de p lt 82 77 86 88 76 72 (l) 84 71 Zgd l Q 3 a5 61 JZdid Zhdlt(l)Zhe/p Zum Zdi Zgd Qal Zhe/pZt-q Q Zhe/pal Zhe/pZ gr Qal di Qal Jd Zgr-ch Zgd-ch 33 Trcs/si1Z Tr gr-ch cs/si1 U D Z Zhdlt(u)h Qal U D gr-c Qa l Zdi D Zefg-m 72 efmZ 82 7 806 8079 Jd 7 5 82 85 Z Z hd Qal 75 84 Zdi 82 79 Zhdlt (7l)8 Qal ZhdlJd tQ(l v Zhe/p 77 Qal Zgr-ch Zgd-ch Qal UJD d Zgr-ch Zg r-c h c) Zhdlt(l) 29 Zhdlt(l) Zhft(l)Z he 62 -m 1 86 84 Zhft(l) 88 34 Jd 80 36 QalZhe� m 2 Z Zh 64 1 Q 65 al Zef e-m g-m 76 Jd Zhe Trcs/si1 -m 1 Jd hdlt(u) 66 Zef 67 g�mZ 54 he-m 2 52 gr lt(l) 84 81 84 Zwfd CZgb Zefmd Zefg-m Qal QalZ 7 984 70 e 07'30" fg-4 Qal Jd Qal Zefg-m Zdi Zhdlt(u) Jd Qal B' Trcs/si1 JdZef 3552'30" Qal Qall g-m Zhablt Jd 1 Qa Zefg-m1 Zdi Z f -2 e g Zefg-3 JdQa l Trcs/si 12 Qal CONTACTS Lithologiccontacts-Distributionandconcentration ofstructuralsymbolsindicatesdegreeofreliability. Contactdashedwhereinfered. Contactdotedwhereconcealed.gradationalcontact FAULTS Faults-Dashedwhereinfered,dotedwhereconcealed. Uindicatesupthrownblock,Dindicatesdownthrownblock. FOLDS Interpretedfoldhingeoflarge scaleoverturnedanticline. Arowindicatesdirectionofplunge.Interpretedfoldhingeoflargescaleoverturnedsyncline.Arowindicatesdirectionofplunge.Interpretedfoldhingeoflargescaledoublyplungingsyncline. ASSORTEDLINES Diabasedike-Dashedwhereinfere, dotedwhereconcealed.Padiddike-inferredPdaddike-inferredgabbrotogabbroporphyrydike-inferredquartzveinorzone-inferedincrosssection-inferredaxialtraceoflarge-scalefoldincrosssection-interpretedfoldformlinesof noncylindricalasymmetricfolds primaryroadsecondaryroad or aronaGeologicalSurvey NorthCarolinaDepartmentofEnvironmentalQuality KennethB.Taylor,StateGeologist ThisgeologicmapwasfundedinpartbytheUSGSNationalCooperativeGeologicMappingProgram DESCRIPTIONOFUNITS SedimentaryUnits Qal�Alluvium:Unconsolidatedpoorlysortedandstratifieddepositsofangulartosubroundedclay,silt,sandandgravel-tocobble-sizedclasts,instreamdrainages.Mayincludepointbars,terracesandnaturalleveesalonglargerstreamfloodplains.StructuralmeasurementsdepictedonthemapwithinQalrepresentoutcropsofcrystalinerockinlierssurroundedbyalluvium. Qcv�Colluvium:Accumulationsofangularcobblesandboulders.PossiblyformedbyQuarternaryslopemovementsinsomecases(rockslide,rockfal,etc). Trcs/si1�SandstonewithinterlayeredsiltstoneoftheChathamGroupLithofaciesAssociationI:Grayish-pink,pinkish-gray,andlight-gray;fine-tocoarse-grained,micaeous,slightlyclayey,moderatelypoortomoderatelywelsorted,subangulartosubroundedarkoseandlithicarkose;darkredtoreddish-brown,verysilty,micaeous,moeratelywellsorted,fine-grained sandstone;anddarkredtoreddish-brown,massive,andthicklylaminated,bioturbated,micaeoustoverymicaeous,siltstoneandmudstone.Muscovieflakesupto3mmdiameterarecommonespecialyinthesiltstone.Fine-grainedflakesofbiotiteinthearkoseandithicarkoseisadistinctiveaccessory.Randomlyorienedandvertical,cylindricalsructuresoftenfiledwith pale-green,fine-grained,quartzsandstoneareinterpretedasburows.Bedding,whenobserved,isparaleltoslightlywavy,occuringasthicklaminationstothinlybedded(0.5cmto5cm).TheserocksareassignedtotheLithofaciesAssociationIofHoffmanandGalagher,1989andWatson,198.TheclasticrocksofLithofaciesAssociationIareinterpretedtohavebeen depositedinabraidedstreamfluvialsystem. MesozoictoPaleozoic(?)IntrusiveUnits Jd�Diabase:Blacktogreenish-black,fine-tomedium-grained,dense,consistsprimarilyofplagioclase,augiteandmaycontainolivine.Occursasdikesupto10ftwide.Diabasetypicalyoccursasspheriodallyweatheredboulderswithagrayish-brownweatheringrind.Redstationlocationindicatesoutcroporbouldersofdiabase. MPzgb�Olivinegabbronorite:Unfoliated,black,medium-tocoarse-grainedgabbronorite.Inthinsection,olivine,plagioclase,orthopyroxeneandclinopyroxenearepresentwithnoapparentmetamorphicoverprint.Infield,rockissimilarinappearancetocoarse-graineddiabase. FaultRocks Trq-brecia�Quartzbrecia:White;massivetobrecciated;vuggyquartz.Typicalycontainsangularclastsofalteredvolcanicrocksuspendedinaquartzmatrix.Somezonesexhibitalaceypaternofintersectingquartzveinswithamatrixofalteredwalrock. MetaintrusiveUnits Pdad�Daciticdikes:Darkgraytogray,finelycrystalline,andlocallyweaklyplagioclaseporphyriticdacitedikesrangingfromlessthanonefoottoseveralfeetwide. Padid�Andesitetodioritedikes:MelanocratictoMesocratic(CI~50togreaterthan50),darkgreentogreengray,aphanitictomedium-grained,metamorphosedandesitetodiorite.Andesitesanddioritesarelocallyplagioclaseporphyritic.Typicalyoccurinmapareaasresistantspheroidalboulders.Localymaybebasaltictogabbroic.Diketrendlinesindicatedwerestrikeof dikemeasuredinoutcroporinterpretedfromadjacentstations.OccurasinfestationinZtgdunitandarepresentinmanymorelocationsthandisplayedonmap. CZtgd�ProspectHilltonaliticgranodioritepluton:Unfoliatedtolocalyveryweakyfoliated,leucocratic(CIlessthan10),verylightgraytoyellowishgray,medium-tocoarse-grained,hypidiomorphicgranular,metamorphosedtonaliticgranoiortetotonalite.Maficmineralspresentinrockaremostcommonlybiotiteintergrownwithchloriteand/orhornblendeintergrownwih actinolite.Locallymuscovite-bearing.Crosscutingpegmatiticdikesofsimilarmineralogypresentinsomeareas.Localybiotiteforms(magmatic?)foliation.Weatheringofrockproducesdistinctivecoarsequartzsandgrainsinsoil.Andesitetodioritedikes(Zadid)arecommonthroughouttheplutonandtypicalyoccurasresistantspheroidalboulders.Plutonmappaterntruncates Virgilinasequencevolcanicsandplutoncontainsfoliatedxenolithsofvolcanicrocks;assuch,theplutonisinterpretedtoberelatedtotheca.546maRoxboropluton(Wortmanetal.,200).CZgr-gd-GranitetogranodioriteoftheProspectHillpluton:Unfoliated,leucocratic(CIlessthan10),pinkishgrayhued,verylightgraytoyelowishgray,fine-tomedium-grained,equigranulartolocalyplaioclaseporphyritic,hypidiomorphicgranular,metamorphosedgranitetograno-diorite.Majormineralsincludewhitefeldspars,quartzand�pinkfeldspars.Maficminerals consistoffine-grainedbiotite/chloriteintergrowthsthatoccurasamorphousmassesandacicularshapedzonesthatresembleamphibolesinhandsample.Maficmineralclotslocallyarealignedformingaweak(magmatic?)foliation. CZgb�Gabbro:Darkgreentoblack,melanocratic,medium-grainedgabbrotoplagioclaseporhyriticfine-grainedgabbro.Presentasadike. EastFaringtonpluton:TheEastFaringtonplutoniscomposedofseveraldistinctgranitoidfaciesbasedonmineralandtexturalcharacteristics.U-Pbzircongeochronologicdata(TadlockandLoewy,2006)indicatethattheEastFarringtonplutonisca.579Ma. Zefg-m�EastFaringtonplutonmainfacies:Unfoliated,orangepinktopinkish-graytogray,medium-tocoarse-grained,equigranulartoslightlyporphyritic,amphibole(va.hornblende?)granite.Amphibolecontentvariesfromapproximately5to10%byvolumeandoccurslocallyasdarkgreen,elongatecrystalsupto1.5cmlongandamorphousintergrowthswithfeldsparandquartzup to0.5cmdiameter.Darkgrayxenoliths/enclavesupto8cmindiameterarecommon.Grainsizebecomesfinerandxenoliths/enclaveslargerneartheplutonedge.Cavities,lessthan1mmindiameter,witheuhedralterminatingcrystalsarecommoninsomespecimens.Inthinsectionthemainfaciescanbeseparatedintotwogroups:1)rockswithaporphyritictexturewithorthoclaseand plagioclasephenocrytsinagroundmassofintergrownorthoclase,plagioclaseandquartzwithagranophyrictexture(micrographictexture)and2)porphyriticandequigranularrocksconsistingoforthoclase,plagioclaseandquartzwithoutagranophyrictextureinmatrix.ThetwovarietiesappeartobeintermingledthroughoutthestudyareaandwithintheadjacentFarringtonQuadrangle (Bradleyetal.,2008). Zefg-m1�EastFaringtonplutonmainfaciesvariety1:Identicaltomainfaciesbutwithdarkgreen,chloritemassesupto4mmdiameter.Inthinsection,thechloritemassesareintergrowthsofchloriteanddarkgreen,fibrousamphibole. Zefg-2�EastFaringtonplutonporphyriticgranite:Gray,fine-grainedgroundmasswithpink-andwhte-coloredphenocrysts(1mmto4mm)oforthoclaseandplagioclase,granite.Anhedraltoacicular-shaped,darkgreen,amphiboles(lessthan1mmto4mmlong)presentingroundmassofquartzandorthoclaseandasintergrowthswithorthoclaseandplagioclasephenocrysts. PresentasseveralmapscalebodiesandasoutcropscaleenclavessurroundedbyEastFarringtonplutonmainfaciesrock.Zefg-3�EastFaringtonplutonfine-grainedgranite:Orangepink,fine-grainedgranite.SimilartextureandmineralogytoEastFaringtonplutonmainfaciesbutwithanoveralfiner-grainedtexture.Whitefeldsparphenocrystscomposelessthan5%ofrock. Zefg-3-EastFaringtonplutonfine-grainedgranite:Orangepink,fine-grainedgranite.SimilartextureandmineralogytoEastFarringtonplutonmainfaciesbutwithanoverallfiner-grainedtexture.Whitefeldsparphenocrystscomposelessthan5%ofrock. Zefg-4�EastFaringtonplutongraygranitoid:Unfoliatedtofoliated,lightgraytolightgreenish-gray,medium-grainedgranitetogranodiorite.White-coloredfeldsparcontentisgreaterthanpinkfeldspars.Foliatedspecimenshavevisiblewhitemicagrowthandlesspinkfeldsparsthanunfoliatedspecimens.FoliatedrockispresentalongportionsofPokeberyCreek,PritchardsMill CreekandCumboBranch.Zefg-6�EastFaringtonplutonsatellitegranitoid:White,creamy,palepink,orpalegreenish;fine-tomedium-grained,localyplagioclase-porphyriticgranite,granodiorite,leucogranite,leucogranodiorite,andquartzmonzodiorite.Containsdistinctiveprismaticamphibolecrystals,locallyacicularanduptoonecm.Amphibole-richenclavesto2cmarepresentlocaly.Atwesterncontact inHeronPondsubdivision,containsenclavesofandcutsfine-grainedgraydioriteandmonzodioriteporphyryoftheZefmdunit. Zefmd�EastFaringtonmonzodioriteporphyryofTerellsCreekarea:Lightgraytodarkgrayis-greenwherefresh,olivedrabweathering,plagioclase-phyricmonzodioriteanddiorite,typicallywihverylowcolorindex.Fine-tomedium-grainedgroundmass,withphenocryststo8mm.Quartzphenocrystsveryrare.Commonlyhasacloudy,splotchy,ormotledappearance.Locally containssalmon-coloredfeldsparphenocrystsand/ororangeovoidsinterpretedascavityfillingorweatheredphenocrysts.Mayhaveathinlightbeigeouterweatheringrind.Weatheredsurfacemaybepited.Locallysulfide-bearing,saussuritized,orstreakedwithtinyepidoteveins.Fine-grainednearmargins.Zwfd�WestFaringtonplutondiorite:Whitetocream-colored,unfoliated,medium-tocoarse-grained,withdarkgreenamphiboe(actinoliteafterhornblende)diorite.Localywithchlorite/biotite;dominantlyequigranularbulocallyweakyplagioclaseporphyritic;ncludesquartzdiorite,grano-diorite,quartzmonzodiorite,andonalite;commonlycontainsovoidenclavesofgreentoblack microdioriteto0.5m;gradestolocalpatchesofmoremaficdioriteandgabbro;finedensetoslabbyhornfelsedcountryrocksoccurlocalyasenclavesandnearcontacts;locallystronglysaussuritizedandpalegreenish;whiteweatheringwithplagioclaseoccuringinpositivereliefgiving�bumpy�texture.HYCOFORMATIONMetaintrusiverocksassociatedwithHycoFormation:upperportionca.613and614Ma(Wortmanetal.,2000)Zgr�Granite:Lightbrownishtobeigeorcreamy,andlocalypalepinkorgreen;medium-tocoarse-grained,equigranularmetamorphosedleucocraticranodioriteandgranite;locallyweaklyporphyriticwithbeta-quartzforms;gradestoquartzporphyryinzonesofcleavagedevelopment;quartzmaybebluish;localyreddishweathering;locallycontainsepidoteand/orchloriteclotspossibly pseudomorphicafterahornblende;feldsparandquartzgrainsresistweatheringandproduceabumpysurface;plagioclaseandquartzphenocrystssitinagranophyricmatrixofalkalifeldsparandquartz.CorrelativetotheChathamgraniteofHauck(1977)inBynumQuadrangle.Zgr2�Granite:Lightpinktopinkandorange;fine-tocoarse-grainedgranite.Maybefoliated.Zgr-di�Granitetodiorite:Compositeplutonexhibitingavarietyofrocktypesrangingfromgranitetodiorite.Lithologiesincludegrayishpink,medium-tocoarse-grainedgranite;pinkish-white,medium-grainedhornblendegranodiorite;anddark-gray,fine-tocoarse-graineddiorite.Zged- � eniodoirendewcthatrkcgtreeocalic,linsstomn1mmdium-rine,loqutgamufactinrhsiriertnedtorbet.itaenodtmpiquiorlzmiorsseadhororitt.rowTptcnlbotiaenndrkmphrbeooilceelss.haed rtin,wcthoisogticninopiii(?)ismphtiebolalnfdhorars(uptmsss.Padiomateeganahyeficesarocitzdeaidnsrmigieizddtnhemoryterhibitaiogoenhsohaor.pLoHlal,adrangdeiLoitasplynishcelde, gt c sotf-teso lioporpaitgdioaatneya taatseum-go4mmdhaoch e il rttgeor niussurl erfeanor i,mfintomGradum-irai:eLuiordaiomentbrackeehtae o4mmgadcifrnarmelyncrpreaoioebMityacnanhbatedies.CdliiegihoycioniasdgienlesprbakntMtn1mmi aeilltfptktltnkawhiakeaidclsplieato5mmelgacesr),porprisroinrnidiiietsteanteinadnahxnportnetiheCclliclqulygrol.eclikahpsua xenolithsarepresent. Zgd-fine�Fine-grainedgranodiorite:Light-graytogreen;rangesfromequigranularfine-grained(lessthan1mm)granodioritetoveryfine-grainedporphyriticgranodioritewithplagioclasephenocrysts(1mmto4mm).Blackcoloredamphibole,whenvisible,occursasphenocrysts(lessthan1mmto1mm)andasintergrowthswithplagioclase;amphiboleintergrowthsdistinguishrockfrom fine-grainedtuffs. Zgd-lueco�Fine-grainedluecocraticgranodiorite:Smallpodsoftantolight-gray,fine-grained(lessthan1mm),luecocraticgranodiorite.Maficspresentinrockarecommonlybiotiteclustersupto1mmindiameter.Plagioglasemineralgrainshavealightgreenishtintfromepidotegrowth. Zagdfine-Fine-grainedalteredgranodiorite:Light-green,fine-grained(lessthan1mm),alteredintrusiverockinterpretedasagranodiorite.Rockisprimarilyafine-grainedmassofheavilysaussuritizedplagioclaseandquartzwithnovisiblemaficmineralsinhandsample.Unitoccursasangularbouldersintwosmallmapbodies. Zgd-gr-p�GranodioritetograniteofPineyMountainCreekarea:Compositeplutonofdominantlymedium-grainedhornblendegranodioritewithlesseramountsofmedium-grainedhornblendegranite.Typicalycontainsdarkgreentoblacklessthan1mmto4mmclotsofactinolitic(?)amphiboleandchloritemasses.Locallycontainspinkish-huedfeldspars. Zgd-di-b�GranodioriteanddioriteoftheBuckwaterCreekPluton:Compositeplutonofdominantlymedium-grained,hornblendegranodiorite;lesseramountsofmedium-grainedhornblendediorite,fine-grainedgranodiorite,anddiorite.Unitcontainsabundantxenolithsofvolcanicrockandenclaves(?)offine-grainedgranodioritetodiorite. Zdi-gd-b�DioriteandgranodioriteoftheBuckwaterCreekPluton:Compositeplutonofdominantlymedium-grainedhornblendediorite;lesseramountsofmedium-grainedhornblendegranodiorite,fine-grainedgranodiorite,porphyriticdioritewithplagioclasephenocrysts;minoramountsofporphyriticgranodioritewithplagioclasephenocrysts,porphyriticgranodioritewithpotassiumfeldsparphenocrysts, andgabbro.Unitcontainsabundantxenolithsofvolcanicrocksandenclaves(?)offine-grainedgranodioritetodiorite. Zgd-porphyritic-PorphyriticgranodioriteoftheBuckwaterCreekPluton:Greenish-graywithapinkish-hue;amphibole-bearing;porphyriticgranodioritewithplagioclasephenocrysts.Plagioclasephenocrystsaregreenfromsaussuritizationandrangefrom2to8mminamatrixofveryfine-grainedquartzandalkali-feldspar.Weatheredsurfaceexhibitadistinctstronglyporphyritictexture.Porphyritic rhyoliteofNewton(1983). Zgd-gb-Granodioritetogabbro:Compositeplutonofdominantlymedium-grained,hornblendegranodiorite;lesseramountsofmedium-grainedhornblendediorite,plagioclaseporphyriticgranodiorite,fine-grainedgranodiorite,anddiorite;minoramountsoffine-grainedgabbro.Fine-grainedgranodioriteanddioritearetypicallygreeninhandsamplefromsaussuritizationofplagioclase.Hornblendeis typicallyalteredtochloriteandactinolitemasses. Zt-qdi�Tonalitetoquartzdiorite:Light-gray,finetomedium-grained,hornblendetonalitetoquartzdiorite.Visiblequartzcontentrangesfrom5%upto20%.Outcropsofthisunitaretypicallyfiner-grained,lighterincolor,andhavevisiblequartzincomparisontotypicalmedium-graineddiorite. Zdi�Diorite:Mesocratic(CI~50),greenish-graytograyish-green,fine-tomedium-grained,hypidiomorphicgranulardiorite.Majormineralsincludeplagioclaseandamphibole.Plagioclasecrystalsaretypicalysericitizedandsaussuritized.Amphibolesaretypicalyalteredtochloriteandactinolitemasses.Maybegabbroiclocaly. Zdi-fine�Fine-graineddiorite:Smalplutonicbodiesofgreen,veryfine-graineddiorite.Therockisgreeninhandsamplefromsaussuritizationofplagioclase. Zqmd-Quartzmonzodiorite:Greenish-graytogray,mesocratic,medium-grained,equigranularquartzmonzodiorite.Majormineralsincludeplagioclaseandhornblende.Infield,rockisindistinguishablefromtypicaldioriteexceptforrarepinkishalkalifeldsparinsomesamples(specificallyonthesouthsideofBlackwoodMountain).Rocktypedesignationbasedonrecalculatedwholerock chemicalanalysesofBland(1972).Zdi-gb�DioritetoGabbro:Greenish-graytogray,medium-grained,equigranular,hornblendedioriteintermingledwithdark-graytogreenish-gray,medium-grainedgabbrowithpyroxene.Plagioclasecrystalsaretypicallysaussuritizedandexhibitagreenishcolor.OutcropswithheavilysaussuritizedplagioclasehaveahighColorIndexcausingdifficultyindistinguishingbetweengabbroanddioriteinthefield.Zgb�Gabbro:GabbrooftheMeadowFlatsplutonisDark-graytogreenish-gray,mesocratictomelanocraticandmedium-grained.Majormineralsincludeplagioclaseandaugite.Inoutcrop,thedioritesandgabbrosareverysimilarinappearanceandaredifficultodistinguishfromeachother.AccordingtoMann,etal(1965),theplagioclasecrystalsarezonedwithcoresofAn53andAn31atthemargins.Augite grains(presentupto3mm)arefringedwithuraliteandaresometimesreplacedbyhornblende,chlorite,ormagnetite.ThemappaternofgabbrowithintheMeadowFlatsplutonwasdrawnincorporatingtheBland(1972)wholerockdatawithfielddatafromthisstudy.AsmallpodofgabbroispresentinthesoutheastcorneroftheHilsboroughquadranglethatisdarkgreen,melanocraticandfine-grained. Zum-Ultramafic:Black,coarse-graine(5mmto10mm),ultramaficrockconsistingmainlyofpoikiliticcrystalsofrelictbrownhornblendethatarepartialyreplacedbyactinoliteandchlorite.Othermineralsincludeserpentine,talc,chlorite,actinolite,andopaqueminerals.Minorrelictorthoyroxeneispresent.Hayes(1962)interpretedtheprotolithsasolivine-richwehrlite(withapproximately50%olivine)and clinopyroxenite.Bulter(1989)interpretedthebodytobeanintrusionofacrystalmushformedbydifferentiationofgabbroicmagmaatdepth.NormalizedwholerockanalysisfromasamplecolectedeastofIronMineHil(CH-2027)plotswithintheolivine-clinopyroxenitefieldonanOl/Opx/Cpx ternarydiagram. MetamorphosedvolcaniclasticsedimentaryandpyroclasticrocksassociatedwithHycoFormation:upperportion(stratigraphicrelationsuncertain)ca.613-616Ma(Wortmanetal.,200;Bowman,2010;andBradleyandMiler,201) Zmi�Porphyriticmaficintrusive:Grayish-greenodark-green,veryhard,plagioclaseporpyriticmaficrock.Greenish-white,euhedral,plagioclasephenocrysts(upto8mm)andblackamphibole/pyroxene?phenocrysts(upto2mm)arepresentinagreenandyelowmotled,veryfine-grained(lessthan1mm)matrix.Typicallyweatherstoroundedbouldersandoutcrops.Theplagioclasephenocrystsweather inpositiverelief,creatingadistinctivebumpyorpustulatesurface.Newton(1983)identifiedthisunitasanamphibole-porphyrylamprophyredike. Zq�Quartzbodies:White,beige,red,andtan;sugarytoporcelaneous;veryfine-tomedium-grainedmassivequartzrocktoquartzite-likerock.Outcropsareusuallymassive.Quartzite-likerockisoccasionalymixedwithsericiteand/orpyrophylite.Theadditionofsericiteand/orpryophyllitegivestheotherwisemassivequartzite-likerockafoliation.Pyriteispresentascubiccrystalsandemptycubicmoldsof crystals(upto12mm).Mapareascontainboulders(uptoseveralfeetindiameter)andoutcropsofwhitecoloredmassivequartz.Zhat(u)�Alteredtufs:Verylightgraytolighgreenishgray(whitishinareas)withredandyelowmotling,alteredvolcaniclasticrocks.Alerationconsistsofsilicified,sericitizedandpyrophylitizedrock.Sericitephyllite,podsofpyrophylite,andquartz+phyrophyliterockallwithlessthan1mmto2mmdiameterweatheredsulfidesarecommon.Relictlithicclastsandkaolinitizedfeldsparcrystalshardsarevisible insomeexposures.Relictstructuresareobliteratedinheavilyalteredrocks.Mapareacontainsboulders(uptoseveralfeetindiameter)andoutcropofmassivemilkyquartzandquartz+sericiterock. Zhe-Epiclastics:Mixedunitofmetaseimentaryrocks.Lithologiespresentincludemudstone,siltstone,sandysiltstone,sandstone,pebblysandstone,andconglomerate.Mudstonesaregreenish-graytogray,typicallysilicified,wihcontinuous,paralleltoslightlywavy,verythintomediumlaminaoccasionallywithsmal-scaleloadingstructures.Siltstonesareghtgreen-graytogray,withcontinuous,paralelto slightlywavy,thinlaminatoverythinbeds,occasionalywithsmal-scaleloadingstructures.Thesiltstonesarecomposedofquartz,sericite,andtracesofablackdetritalheavyminerals(lessthan1mmindiameter).Siltstonesaretypicalyinterbeddedwiththesandstones.Sandstonesaredark-gray,gray,greenish-gray,grayish-green,litharentesandfeldspathiclitharenitescomposedofvolcanicrockfragments, feldspar,quartz,andrareintrusiverockfragments.Texturesrangefromfine-grained,andwellsortedtoverycoarse-grained,andmoderatelypoorlysorted.Beddinginthesandstonesiscontinuous,paralleltoinclined,thinlaminatothinbeds;alsomassivebeddingandcross-bedsarepresent.Individualbedsaresometimesgradedfromsand-sizeosilt-sizewithabruptuppersurfaces.Conglomeratesinclude matrixsupportedandclastsupportepolymicticconglomeratecomposedofangulartorounded,pebblestolargecobbles(upo30cm).Conglomeratesaregeneralymassivebedded,rarelywithanyimbricationoftheclasts.Clasttypesinclude:dark-graytogray,angulartosubangular,microcrystalinevolcanicrockfragments;black,subangulartosubrounded,plagioclase-porphyriticdacite;blacktodarkgray, subrounded,flow-bandeddacite;andgreenish-graytograyish-green,roundedtowellrounded,finetocoarseplagioclasecrystaltuff.Rareclasttypesinclude:white,subangulartorounded,graniteandgranodiorite(upto12cm);dark-brown,rounded,vesicularbasalt(upto2.5cm);andgray,angularsiltstone(upto25cm).Sandstoneandconglomeratebedsoftenfillscourchannelsinthesiltstones. Zhe-m1andZhe-m2�MorganCreekepiclastics:Containswellbedded,greenish-graytogray,siltstone,sandysiltstone,sandstone,conglomeraticsandstone,andconglomerate.Theunitwasdividedntotwolithofacies,Ze-m1andZe-m2:Zme1isexposedmainlyalongMorganCreek;itismostlywelbeddedsiltstoneswithlessersandstoneandconglomeratebeds;Ze-m2,occurstothesouthandsouthwestofZe-m1and isoveralcoarser,containingmostlysandstonesandconglomerateswithlesserwelbeddedsiltstones.Siltstonesrangefromthinlyaminatedtoverythinlybedded(lessthan1mmto10mm)withindividualbedsthatcanbetracedcontinuouslyintheoutcrops.Sandstoneandconglomeratebedsoftenfillscourchannelsinthesiltstones.Theconglomeratesrangefrommatrix-supportedtoclast-supported,containsubroundedto roundedlithicclastsofporphyriticdacite,aphaniticvolcanicrock,andgranitoidinasilttosandmatrix.Individualbedsaretypicalygradedfromsand-sizetosilt-sizewithabruptuppersurfaces. Zhe/p-Mixedepiclastic-pyroclasticrocks:Grayish-greentogreenish-gray,tuffaceoussandstones,conglomeraticsandstones,siltstonesandminorphylite.Thesiltstonestypicalyareweaklyphylliic.Containslesseramountsoffine-tocoarsetuffandlapilituff.Tuffsaredifferentiatedfromothervolcaniclasticrocksbythepresenceofzonesofcryptocrystalinetexturethatexhibitconchoidal-likefracturesinbetween foliationdomains.Minorandesitictobasalticlavasandtuffspresent.Silicifiedand/orsericitizedalteredrocksimilartoZhatunitarelocalypresent.UnitisinterpretedtogradeintoZhe/plunit.ContactwithZhe/pldesignatedatfirstoccurenceofdaciticlavas. Zhe/p-d�Mixedepiclastic-pyroclasticrocksoftheDukequaryarea:Grayish-greentogreenish-gray,massivetostronglyfoliated,tuffaceoussandstones,conglomeraticsandstones,siltstones,phyllite,tuffandlapilituff(locallywelded).Tuffsaredifferentiatedfromothervolcaniclasticrocksbythepresenceofzonesofcryptocrystalinetexturethatexhibitconchoidal-likefracturesinbetweenfoliationdomains.Minor lithologiesincludeinterlayersofamygdaloidalbasaltandfine-grainedmafictuffsthathavebeenalteredtoepidote/chlorite.UnitappearstocontainmorefelsictuffsthanZe/punit. Zhe/p�n-Mixedepiclastic-pyroclasticrocksofNevilleCreekarea:Heterogeneousunitoffelsictointermediatecompositiontuffsandlavas,mudstone,siltstone,tuffaceoussandstonesandconglomeraticsandstones.UnitappearstocontainmoreandesitictobasalticlavasandtuffsthanZe/punit. Zhe/pl-Mixedepiclastic-pyroclasticrockswithinterlayereddaciticlavas:Grayish-greentogreenish-gray,locallywithdistinctiveredish-grayormarontolavendercoloration;conglomerate,conglomeraticsandstone,sandstone,siltstoneandmudstone.Lithoogiesarelocalybedded;locallytuffaceouswithacryptocrystalline-likegroundmass.Siltstonesarelocallyphylitic.Locallycontaininterbeddeddaciticlavas idenicaltoZhdltunit.Containslesseramountsoffine-tocoarsetuffandlapiituffwithacryptocrystalline-likegroundmass.Minorandesitictobasalticlavasandtuffspresent.Silicifiedand/orsericitizedalteredrocksimilartoZhatunitarelocalypresent.Conglomeratesandconglomeraticsandstonestypicalycontainsubroundedtoangularclastsofdaciteinaclasticmatrix.Zhe/pldistinguishedfromZhe/pbypresenceof dacitesandisinterpretedtorepresentafacieschangetoanareamoreproximaltotheactivevolcaniccenterscomparedtoZe/p.Cloudetal.(1976)fossillocalityfromunitinDurhamCounty(Bradleyetal.,201b). Zhp/e�Mixedpyroclastic-epiclastics:Graytogreen,felsictuffsinterlayedwithmudstone,siltstone,andsandstoneanddistinctiveimmature,monomictic,conglomeraticsandstonetoconglomeratecontainingsubangulartoangularclastsofplagioclaseporphyriticdacite.Minorandesitictobasalticlavasandtuffs.ThecontactwiththeZhdlt(u)unitisinterepretedtobegradational. Zhdlstnw �tiicilavacstnadetufsnft.ehpdaetpeortaeontefteedtoFaemeinceeentest-rusryetsorvdrkryryalilcntaohastssocdiactd,porpwtyiteaiaetnihhlgtuoflasepieerprortess,sndsoldbpnroelaaicitfededposdatdnirnlweudfesorrufaecdatefwstnhreeaddainnguegatennisf-darytetdgaeisgheenntfncursufsmcaeclgepooldsrsadeufadatpclcuksofLoha/p,l,nheelyrsoZe/pummits.eWcnmlneaae(2000)radcngltesaic a t(u)oDacacaarprseohuepcr rinorpreHychovreno:Grhreixhgaoegsa,sowei ipnniicatieihdomicdormctiwo.tpaicsehnncytdaapiowicadddscelWleins,aof-tldtfesworkitufdgehtatvurscfdormreohgcaoomyhT-rueioictf,arspaaicassurouecynldfbynlsaiiitf.Zceyitalehfinaturtgaetrt.oeom t snd eihdttelss etTis hto baton ivahious,rus aehrf Tefarteefyct.ow alfsso ielil:ioirs. ,eaopsl ttclro flZ/pror oroom lnporr anageof615.7+3.7/-1.9MaU-PbzircondateforadacitictufffromtheunitwithintheRougemontquadrangle(Bradleyetal.,201b). Zhdsi(u)�DaciticshallowintrusiveoftheupperportionoftheHycoFormation:Gray-green,lightgreentogreen,greenish-graytolightgray;dacite,plagioclaseporphyrticdacitewithagranular-texturedgroundmasstomicro-granodiorte(intrusivetexturevisiblewith7xhandlens).Locallyfne-tomediumgranedgranodioritepresent.Plagioclasephenocrysts,whenpresent,rangefromessthan1mmto4mm.Black cooreamphibole,whenvisible,occursasphenocrysts(lessthan1mmto1mm)andasintergrowthswithplagioclase.Amphiboleintergrowthsdistinguishrockfromfine-grainetuffs.Rockfromtheactivequarryincludesgreenish-graytolightgray;aphanitictoweaklyplagioclaseporphyriticdacitetomicro-granodiorite.Relictplagioclasephenocrystsaresausseritizedinamatrixofrecrystallizedfeldsparandquartzwithdark coloredclots(lessthan1mmto4mm)interpretedinhandsampleaschlorite(?)massesand/orrelictenclavesofdarkgraydacite.Containslesseramountsofdarkgray,aphaniticdacite.Interpretedasshalowlyemplaceddaciteprobablyco-magmaticwithZdlt(u)unit.Zhablt�Andesitictobasalticlavasandtufs:Green,gray-green,gray,darkgrayandblack;typicallyunfoliated,amygdaloidal,plagioclaseporphyritic,amphibole/pyroxeneporphyriticandaphanitic;andesitictobasalticlavasandshalowintrusions.Hyaloclastictextureiscommonandimpartsafragmentaltexturesimilartoalithictuffonsomeoutcrops.Localyinterlayeredwithmeta-sedimentsidenticaltotheZhe/plandZhe/punit.Zhasi-Andesiticshallowintrusive:Grayish-greentolightgreen,plagioclaseporphyriticandesitewithagranular-texturedgroundmasstoveryfine-graineddiorite(withintrusivetexturevisiblewith7xhandlens).Containslesseramountsoffine-tomediumgraineddiorite.Plagioclasephenocryststypicalyrangefrom1mmto4mm.Darkgreentoblackcoloredamphibole,whenpresent,occursasphenocrysts(lessthan1mmto 1mm)andasintergrowthswithplagioclase.Screensofvolcaniclasticrocksarecommonlypresent.Zhabsi�Andesitictobasalticshallowintrusive:Distinctive;verydark-graytoblack;aphaniticgroundmass;magnetic;andesitetobasaltporphyry.Inthinsectiontherockiscomposedofaveryfinematrixofplagioclaselathsandapparentrelictamygdulesin-filedwithepidoteandquartz.PresentintheCurieHillareaontheHilsboroughquadrangle.Zhiflt�Intermediatetofelsiclavasandtufs:Heterogenousunitoffelsictointermediatecompositiontuffsandwithlesserinterlayersofandesitictobasalticlavasandepiclasticrocks.Porphyriticandesitictobasalaticlithologiesmaybeshallowintrusions.Felsictuffsarelocallyphyllitic.InterpretedasequivalenttotheColinsCreekandColinsMountainunitsofHauck(1977).MetaintrusiverocksassociatedwithHycoFormation:lowerportion(stratigraphicrelationsuncertain)ca.630Ma(Wortmanetal.,2000)Zgr-ch�Granite:Typicalymassive,fine-tomedium-grainedwithdarkgreenamhiboles(commonlyrimmedbyepidoteandchlorite)and+/-biotite.Light-pinktopink,alkalifeldsparsareprominentandgivetherockapinkishhue.Orange-pinktograyish-orangepink,fine-grainedaplitewithasub-graphitictextureispresentindikesrangingfromcentimeterstometersinwidth.Rocksofgraniticcompositionoccurprimarilywithinthe informallynamedChapelHilpluton.GraniteoftheChapelHillplutonhasaninterpretedU-Pbzirconcrystalizationageof633+2/-1.5Ma(Wortmanetal.,2000).AnunpublishedU-Pbzirconageof631.6+/-7.9MawasalsoreportedbyMehlop(1994)fortheChapelHilpluton.Zgd-ch�Granodiorite:Leucocratictomesocratic,fine-tomedium-grained,equigranulartoporphyriticgranodiorite.InthecentralandsouthernportionsoftheChapelHillquadranglethegranodioriteismainlywhitish-gray,fine-tomedium-grained,biotite,+/-hornblendegranodioritewithminorpink-coloredalkalifeldspar.Plagioclasegrainsareoftensericitizedandsaussuritizedandexhibitagreenishcolorthroughouttheunit.MetamorphosedvolcaniclasticsedimentaryandpyroclasticrocksassociatedwithHycoFormation:lowerportion(stratigraphicrelationsuncertain)ca.629-633Ma(Wortmanetal.,200andBradleyandMiller,201) STRUCTURALSYMBOLS Zhat(l)�AlteredtufsofthelowerportionoftheHycoFormation:Verylightgraytolightgreenishgray(whitishinareas)withredandyelowmotling.Alterationconsistsofsilicified,sericitizedandpyrophylitizedrock.Sericitephyllite,podsofpyrophyllite,andquartz+phyrophyliterockallwithlessthan1mmto2mmdiameterweatheredsulfidesarecommon.Fine-grainedchloritoidporphyroblasts(lessthan1mm)arepresent insomepyrophylitebearingrocks.Relictlithicclastsandkaolinitizedfeldsparcrystalshardsarevisibleinsomeexposures.Relictstructuresareobliteratedinheavilyalteredrocks.Mapareacontainsboulders(uptoseveralfeetindiameter)andoutcropofmassivemilkyquartzandquartz+sericiterock.61 sbterikdeinandnddipoayfeprinimgary stomprikeocfvioenrtfioclalaprtiinmaanrydvolcaendicin tehxurst�lyMatrexsauurpeortcceiddets:Grlasteanregirnycorportgretnd;wetokalyafpoildalyteetoweilelntoldiptedckgaeorxfsupporeiettdM;poaymeitmpclaacpidlvufsufabndatuinfmracssifs.Angblarerosuilbn-drouliddesdaldtilaraagrs.Detaciatnigtofromndsessictlaana1mmupsoallprtsen.diaeeUniisne eesrsdmnesn-rupivvolailsiceposiin hcetayn dfevocnicastcdbriandentand dgalr catio/orwlg Ztmamorimtp atufnalcse-aoaeeinarirdsdmefeaa;matisdmne.lybcei;elitiasmrfebecalows,suuatalasne,ni/orhcfhmnsrceaelithvlcyo0.e5mtmtr.titrprtdaaeeietdyetecncatd twihtxurlumoiidlaliesrie strikeofverticalbeddingandlayering 54 strikeanddipoffoliation Zhft(l)-Felsictufs:Grayish-greentogreenish-grayandsilvery-gray;massvetofoliaedvolcaniclasticpyroclasticrocksconsistingoffine-tocoarsetuffs,lapilituffsandminorweldedtuffs.Tuffsaredifferentiatedfromothervolcaniclasticrocksbythepresenceofzonesofcryptocrystalinetexturethatexhibitconchoidal-likefracturesinbetweenfoliationdomains.Layering rangesfrommassivetothinlybedded.Containslesseramountsofvolcaniclaticsedimentaryrocksconsistingofvolcanicsandstones,andgreywackeswithminorsiltstonesandphyllite.74 strikeanddipofoverturnedbedding strikeofverticalfoliation Zhft-b(l)�FelsictufsoftheBlackwoodarea:Green-graytograycoarsetuffandlapillituff.Plagioclasecrstalsandcrystalfragmentsarecommon.Lithicclasttypesincludesdark-graytoblack;magnetic;1to70mm;cryptocrystalinelava,orclastsofporphyriticlavawithfeldsparphenocrysts.PorphyriticclastsareidenticaltotheporphyriticphasesofunitZdlt.Outcrops andthinsectionsshowaprominentweldingand/orcompactionfoliationwithfiamme-shapedclasts.Outcropstypicallyoccurasveryresistantfin-likeoutcrops.strikeanddipofprimaryvolcanic 77 Zhdlt(l)�DaciticlavasandtufsofthelowerportionoftheHycoFormation:Distinctivegraytodarkgray,siliceous,crytocrystalinedacite,porphyriticdacitewithplagioclasephenocrysts,andflowbandeddacite.Weldedandnon-weldedtuffsassociatedwiththelavasinclude:greenish-graytograyish-green,finetuff,coarseplagioclasecrystaltuff;lapilituff;andtuffbreccia.Thedacitesareinterpretedtohavebeencoherent 86 compactionand/orwelding strikeanddipofcleavage extrusivesorveryshalowintrusionsassociatedwithdomeformation.Thetuffsareinterpretedasepisodicpyroclasticflowdeposits,airfalltuffsorreworkedtuffsgeneratedduringformationofdacitedomes.Wortmanetal.(200)reporta632.9+2.6/-1.9MazircondatefromasamplewithintheunitintheChapelHil quadrangle. strikeofverticalcleavage Zhdlt-a�Altereddaciticlavasandtufs:Graytodark-gray;massivetofoliated,aphaniticrocks.Rareplagioclasecrystalfragmentsarepresent.5�10%accessorysulfidemineralscommonlypresent.Rockisrelativelyfeatureless.Interpretedasdaciticlavasandtuffs.PresentintheCatesCreekareasoutheastofHilsborough.Zhdlt-porph-PorphyriticdaciteassociatedwithZdlt:Dominantlylightgraytomediumdarkgray,porphyriticdacite.Acicularshapedzonesofmaficmineralphenocrystsresembleamphibolesinhandsampleandconsistoffine-grainedactinolite/chlorite(?)intergrowthsunder20Xmagnification.Dacitesarelocalysiliceousandflowbanded.Unitmaycontaintuffsandis interpretedasaveryshalowintrusivecloselyassociatedwithZdltdomes. OTHERPOINTS Zhdsi(l)�DaciticshallowintrusiveofthelowerportionoftheHycoFormation:Gray-green,lihtgreentogreen;plagioclaseporphyriticdacitewithagranular-texturedgroundmasstomicro-granodiorite(intrusivetexturevisiblewh7xhandlens).Containslesseramountsoffine-tomediumgrainedgranodiorite.Plagioclasephenocryststypicalyrangefrom1mmto4mm. MineorProspect-abandoned Blackcoloredamphibole,whenvisible,occursasphenocrysts(lessthan1mmto1mm)andasintergrowthswithplagioclase.Amphiboleintergrowthsdistinguishrockfromfine-grainedtuffs.Enclavesofdarkgray,plagioclaseporphyriticdacitearecommonandattimesgiverockapsuedo-clasticappearance.BradleyandMiler(201)reportanageof628.5�1MaforadacitefromthisunitinsouthernOrangeCounty. - Quuaarrrryy-aacbtainvdeoned Zhadlt�Andesitictodaciticlavasandtufs:Distinctiveblacktodarkgray;porphyriticlavawithplagioclasephenocrysts(upto4mm),andflowbandedlavawithlocalamygdules.Interlayedwiththelavasaregraytoblack;weldedandnon-welded;coarsetuff,lapillituff,andtuffbreccia. Zhqdp-Quartzdaciteporphyry:Stronglyporphyriticwithaphaniticgroundmassandsub-toeuhedralphenocrysts(2-6mm)ofwhitetosalmonplagioclaseandgraytodarkgray(beta-)quartz;phenocryststypicalyconstitute20to25%oftherock;localweakalignmentofplagioclase;interpretedaseitherlavaflowsorshalowintrusivespossiblyassociatedwithdomes. U-Pbagedatelocation RAEFERENCES 19-urraypyrophylliteprospect-abandoned Disclaimer: ThisgeologicmapwasfundedinpartbytheUSGSNationalCooperativeGeologicMappingProgramunder en,E.P.,andWilson,W.F.,1968,GeologyandmineralresourcesofOrangeCounty,NorthCaroina:DivisionofMineralResources,NorthCarolinaDepartmentofConservationandDevelopment,Buletin81,58p. 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s,..,Gay,N.K.,Fuemmeler,S.J,204,GeologicmapoftheChapelHil7.5-minutequadrangle,OrangeandDurhamCounties,NorthCarolina:NorthCarolinaGeologicalSurveyOpen-fileReport2004-01Revision-02(208),scale1:24,0,incolor. thispreliminarymapmayoccur. rae,..,Philips,C.M.,Witanachchi,C.,Ward,A.N.,Clark,T.W.,2004,GeologicmapoftheNorthwestDurham7.5-minutequadrangle,DurhamandOrangeCounties,NorthCarolina:NorthCarolinaGeologicalSurveyOpen-fileReport2004-03aRevision-01(2010),scale1:24,000,incolor. 3-OBccconneecaheeyMou-aantdainnqudarry-abandoned ,0010 0 ,00 00 ,00 20 1,00 80 2,00 Tiaadepaaornormtossumtdfbiainihtenetnigtahnt aay,..,P.J.,,GnyGylT,2006elagcovarvfitwoeinsworouelohc-aiueoathrnhla,OreHnleibnorouytnCrofnnd:Nor-hiatqulnGrnooes,OralSurvnaydehfeRportt2005s,Ca02,slaeea,NorCaolor.i, aly,P.J.,nClT.,dtTGogoftCaeHl 4-aoqurrbnoe 30 ,50 30 6,0 90 1,00 50 1,00 10 hsmpnxlntyifainibieorpulctowthudrsadnhtteUie Brrdlee aad,K.a,C,N.K.ark,,2005,G.W.oo,AinmpoeehHflebgogg7.5immppnintgqufdeaCgeplaig,HCoulst,NorghahdaElaia7.5mtnCueroiaadaeglgicageenOpDurn-aimCoulenie-roinactlr1:24,00,nethincrolnainBrde adark,.Weiors,heeloyhehplil, 5-Coile(Eno)quarry-abandoned Feet NorthCarolinaStatePlaneNAD83meterscoordinatesystem, StatesGovernmentisauthorizedtoreproduceanddistributereprintsforgovernmenaluse.TheviewsandHilsboroughandEfland7.5-minuteQuadrangles,OrangeandDurhamCounties,CarolinaTerane,NorthCarolina,CarolinaGeologicaSocietyFieldTripGuidebookforthe206annualmeeting,pp.1-16. 6-uarrbuildingstone-active LambertConformalConicprojection conclusionscontainedinthisdocumentarethoseoftheauthorsandshouldnotbeinterpretedasnecessarily Bradley,P.J.,Gay,K.,Clark,T.W.,2006b,FieldtripguidetothegeologyoftheChapelHil,HilsboroughandEfland7.5-minutequadranges,Carolinaterane,NorthCarolina,inBradley,P.J.,andClark,T.W.,editors,TheGeologyoftheChapelHil, 7-uarrcrusesone-acve 10.50 1 2 3 4 5 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Tadlock,K.A.andLoewy,S.L.,206,IsotopiccharacterizationoftheFaringtonpluton:constrainingtheVirgilinaorogeny,inBradley,P.J.,andClark,T.W.,editors,TheGeologyoftheChapelHill,HilsboroughandEfland7.5-minuteQuadrangles,Orangeand DurhamCounties,CarolinaTerane,NorthCarolina,CarolinaGeologicalSocietyFieldTripGuidebookforthe2006annuameeting,pp.17-21. aener,..,4,reamoavaraonnearnonneouscomex,aamanranecounties,NorthCarolina,unpublishedM.S.thesis,UniversityofNorthCarolinaatChapelHil,51p. agener,H.D.,1965,ArealmodalvariationintheFaringtonigneouscomplex,ChathamandOrangeCounties,NorthCarolina,SoutheasternGeology,v.6,no.2,p.49-7. ortman,G.L.,Samson,S.D.,andHibbard,J.P.,2000,PreciseU-PbzirconconstraintsontheearliestmagmatichistoryoftheCarolinaterane,JournalofGeology,v.108,pp.321-338. Wright,J.E.,1974,GeologyoftheCarolinaslatebeltinthevicinityofDurham,NorthCarolina,unpublishedM.S.thesis,VirginiaPolytechnicInstituteandStateUniversity,78p. 3 3600'00" AA Zdi-gd-b7209'' PdadDike Zhe/p Zhe/p Zhablt Zhft(l) Zhft(l) Zhft(l) 07'29' Zhablt Zhe/p Zhdlt(l) Zhft(l) -1271' CZtgd CZtgd PadidDike Zhat(l) Zhadlt Zhadlt Zgd-di-b Zhat(l) -1271' PadidDike Zhft(l) Trq-breccia Zhdlt(l) Zhdlt(l) PadidDike Zgd-gr-p Zhdsi(l) Zdi-gd-b -3271' -3271' INTRODUCTIONPre-MesozoiccrystalinerocksinOrangeCountyarepartoftheVirgilinasequenceoftheNeoproterozoictoCambrianCarolinateraneoftheCarolinaZone(HarrisandGlover,1988;Hibbardetal.,202;andHibbardeal2006).Inthevicinityofthemaparea,theVirgilinasequencecanbeseparatedintotwolithotectonicunits:1)theHycoFormationand2)the AaronFormation.TheHycoFormationconsistsofca.615to633Ma(Wortmanetal.,200;Bowman,2010;BradleyandMiller,201.)metamorphosedlayeredvolcaniclasticrocksandplutonicrocks.Availableagedates(Wortmanetal.,2000;BradleyandMiler,201)indicatetheHycoFormationinOrangeandDurhamCountiesmaybedividedintolower (ca.630Ma)andupper(ca.615Ma)members(informal)withanapparentinterveninghiatusofmagmatism.InsouthernOrangeCounty,HycoFormationunitsareintrudedbytheca.579Ma(TadlockandLoewy,206)EastFarringtonplutonandassociatedWestFaringtonpluton.TheAaronFormation(notpresentinOrangeCounty)consistsofmetamorphosed layeredvolcaniclasticrockswithyoungestdetritalzirconsofca.578and588Ma(Samsonetal.,2001andPolock,2007,respectively).TheVirglinasequencewasfoldedandsubjectedtolowgrademetamorphismduringtheca.578to554Ma(Pollock,2007)Virgilinadeformation(GloverandSinha,1973;HarrisandGlover,1985;HarisandGlover,198;andHibbardandSamson,1995).Inthemaparea,originallayeringofVirgilinasequencelithologiesareinterpretedtorangefromshallowlyto steeplydippingduetoopentoisoclinalfoldsthatarelocalyoverturnedtothesoutheast.ThenorthwestcornerofOrangeCountyisunderlainbytheProspectHillpluton.TheProspectHillplutonintrudesfoliatedandfoldedHycoFormationunitsandiscorrelatedwiththeca.546MaRoxboropluton(Wortmanetal.,2000).Mapunitsofmeta-volcaniclasticrocksincludevariouslihoogiesthawhengroupedtogetherareinterpretedtoindicategeneralenvironmentsofdeposition(orlihofacies).Thedacitclavasandtuffsunitisinterpretedtorepresentdaciticdomesandproximalpyroclastics.Thefelsictuffsunitsareinterpretedtorepresentairfaltuffsandassociatedvolcanosedimentary rocksdepositeddistalfromavent.Theandesitictobasalticlavasandtuffsunitisinterpretedtorepresenteruptionofintermediatetomaficlavaflowsandassociatedpyroclasticdeposits.Theepiclasticandepiclastic/pyroclasticunitsareinterpretedtorepresentdepositionfromtheerosionofdormantandactivevolcanichighlands.TheVermiformaantiquafossillocalityreportedbyCloudetal.(1976)ispresentwithintheZhe/plunitinadjacentDurhamCountyalongtheSouthForkoftheLitleRiver.Seilacheretal.(200)indicatesthefossilmaybeatectographandnotatruefossil.ThesoutheasterncorneroftheCountyisunderlainbyTriassic-agedsedimentaryrocksoftheDurhamsub-basinoftheDeepRiverMesozoicbasin.SillsanddikesofJurassicageddiabaseintrudetheTriassicsediments.DiabasedikesalsointrudethecrystalinerocksoftheCounty.QuaternaryagedalluviumispresentinmostmajordrainagesthroughouttheCounty.Alpre-MesozoicrocksnOrangeCountyhavebeenmetamorphosedtoatleastthechloritezoneofthegreenschistmetamorphicfaces.Manyoftherocksdisplayaweakorstrongmetamorphicfoliation.Althoughsubjectedtometamorphism,therocksretainrelictigneous,pyroclastic,andsedimentarytexturesandstructuresthatalowfortheidentificationofprotolith rocks.Assuch,theprefix�meta�isnotincludedinthenomenclatureofthepre-Mesozoicrocksdescribedinthequadrangle.Jurassicdiabasedikesareunmetamorphosed.ThenomenclatureofheInternationalUnionofGeologicalSciencessubcommissiononigneousandvolcanicrocks(IUGS)afterLeMaitre(2002)isusedinclassificationandnamingoftheunits.Theclassificationandnamingoftherocksisbasedonrelictigneoustextures,modalmineralassemblages,ornormalizedmineralassemblageswhenwhole-rockgeochemical dataisavailable.PastworkerswithintheCountyandadjacentareas(AllenandWilson,1968;Black,197;Bland,1972;Butler,1963and1964;Chiuli,1987;Clark,1957;Hauck,197;Hayes,1962;Kirstein,1956;Mannetal.,1965;McConnel,1974;McConnelandGlover,1982;Newton1983;Wagener,1964and1965;andWright,1974)haveusedvarous nomenclaturesystemsfortheigneousrocks.Therawdata,whenavailable,oftheseearlierworkerswasrecalculatedandplotedonternarydiagramsandclassifiedbasedonIUGSnomenclature.PyroclasticrockterminologyfollowsthatofFisherandSchminke(984).ApreliminaryreviewoftheareageologyisprovidedinBradleyetal.,206aandb.Thismapisa compilationofmodifiedandediteddatafromtheOrangeCountyportionsoftheFarrington(Bradleyetal.,2007),Bynum(BradleyandStoddard,201),ChapelHil(Bradleyeta.,2004),WhiteCross(BradleyandStoddard,208),Saxapahaw(Bradleyetal.,201a),NorthwestDurham(Bradleyetal.,2004),Hilsborough(BradleyandGay,2005),Efland(Bradleyetal., 2006c),Mebane(Bradley,201),Rougemont(Bradleyetal.,201b),Caldwel(Bradleyetal.,2010),CedarGrove(Hannaetal.,2010)andBurlingtonNortheast(HannaandBradley,2010)geologicmaps. GEOLOGICMAPOFORANGECOUNTY,NORTHCAROLINA NCGSOPENFILEREPORT2016-05 nve t to ro lon ngG em e BurliNE Cedar Caldw Roug gh st bane land orou hwem ta Me Ef lsb orrh i Nu slt HD w os Hi es axapaha WhiteCr Chapel SouDthuwrham S n num ingto B y ar F crosssectionscale:1:50000elevationinfeetnoverticalexaggeration B BaldMountain B' 737' Zhablt Zhablt Zhdlt(l) Zhft(l) Zhe Zhe/p Trcs/si1 Zhe-m2 Jd 737' Ze/p-d 0' Zhe/p Zgd-gb Zgd-gb Zhablt Zdi Zgd Zhe/p Zgd Zhe/p Zgr-ch 0' Zhdlt(l) Zhft(l)Zhft(l) Trcs/si1 Zhe/p Zgd-gb Zhe Zdi Zgb -1263' -1263' Ze/p-d Zhft(l) Zhdlt(l) Zhdlt(l) Zhft-b(l)ZhZfht(fl(t)-l)b Zdi Zhe/p ZhftZ(hl)dlt(l) Zt-qdi Zgd-ch Zgr-ch Zgr-ch Zhe-m2 Zhe-m2 Zhablt Zhft(l) Zhft(l) Zhft(l) -3263' Zhft(l) Zhft(l) -3263' Zhdlt(l) Zgd Zhft(l) ScanwtoitGheosmaPDrFtpohfonemapfo. rlinkThirdpartyApprequired.