|j3452'4 . ?1/S Y Atlos 157 D 'l I . 57i1. 1970 t: i' nlogy, Minerol Resources ond { *iroirn"ntol Geology of the ,lmyro Quodrongle, .Lebonon rd Do0phin Counties
rn R. Geyer
tl \ /:
il.
\ lt',-l'
,!- .-_ - l- " COMMONWEAITHo OF PENNSYIVANIA ,', srATE PtANNtNc boano ' lrving Hond, Execulive Director , ,, ,. i BUR.EAU oF ; . , ToPoGRApxtc ri GEoroctc suRvEy t Arthur A..Silcolow, Stote Geologist a ., i:.q ,, 55Hllillil{3rIJ*rfl3.{_ rrBRARy $rp ? \Y" ' ,., i:, i'Ittt$' / '.:.,1. - r'' .s - tit-
tn':u .i y'" .\ +i,11'i'-'- t-
Ot-r/F E/ / f 't>bt>{ 24r BUIIETIN A 157 D
Geology, Minerol Resources ond Environmentol Geology of the Polmyro Quodrongle, Lebonon ond Douphin Counties
by Alon R. Geyer Pennsylvoniq Geologicol Survey
PENNSYIVANIA GEOLOGICAT SURVEY FOURTH SERIES HARRISBURG
l97A Copl'rightcd 1970 by tl"re C Quotatiotrs flotn this book miry be publishcd if crcdit is given to thc Pcrtrrsylvania Cicological Strrvey COVER SKETCH BY ALBERT VAN OI.DEN IS TAKIIN IIRO:\I FIGTJRE 14 IN TEXT. ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PURCHASED FROM BUREAU OF PUBLICATIONS DEPARf'MENT OF' PROPERTY AND SUPPLIES HAII.RISBURG, PA. 17125 ll PREFACE 'l'lris rL'lr(,lt tlctr t'ilrcs tltc'licttct':rl gcologv ol':rtr ;rlc;r itr l,clr:rnein (-lornttv llotrtrtlctl ()n tllc \\'c\t lr) t lrc lirr orrglr o1' lt.rlntr t':r, ()ll tlrc c:rst ll1' tlrc \/illlrgc ol'l;ottt:rtt:r. ()n tlrc sorrtlr lrr tlte Yill;rge of l];rrlrm;rrrrillc,:rnrl orr tltc ttol tlr lrr tltt: \'illlgc ol' Ilcllcsrorc. IIislr-c:rltirrrrr lirrrc:tonc, one of I)cltltrtlr:tlti;t's IIr()\t rirluetl ntittcr;rl r'('\()ul'((:\, is lotrrrtl in this iu'eil. l)et;rilctl ttt.tps ol tlris linrcrtorrc, tlrc,\nrrville l,irncstone, its clrar':rcrcr'- isti tv CONTENTS Pns, Pr-cflrc ... lll .{llstr:r ct I Introtlu( tion 2 (icrro':rl 2 o 'I'olrogrrrplrr' J Ack norrlccl.q-errr cr r t s 5 Stra t igr';r lllr r' 5 Camllli:rn Svrtem 5 Btrff;rlo .S;lrings Forlnation . . . ) Conocochel.guc Crorrp I Snitz Cl'eek Forrlation I Sclr:rfferstou'n Forrnation I Ifillb;rc h Formation 8 Richlnnrl l;orrnatiol'r ...... 8 Orrlovician Svstenr/ 9 Ileeknr;rnton'n Gr"orrp I Stonelrenge Formation I I{i< lrcnlla<'lr For-rn:r tiorr l0 l,plcr Folmatior] . . . . . r0 Ontelatrnee Formation ll Annville I.irncstonc . . l2 It'I1'erstorvn Li meston e r3 Herslrel' Linrestone r3 I[;rrtinsbtrrg Forrnation Iir Gcneral r5 Shale lir Srnrlstone l6 Clonglomcrate t7 Limcstone 17 Ple-'I'riassic Rocks o[ Uncertain Agc r9 llill Hill Slate . r9 Triassic Svstenr :0 Harnmcr Creck Formation 20 I)iabase :2 Strur:ttn'e :,1 Genernl 2-l fircat \ralle)' Secrion 2ir Folcls 2ir Fatrl ts o1 Triassic I-orvland Scction 29 Folds 29 v Page (ir;lcbrorrk ;\ntit lirtc 29 I'lainvillc Syrrtlirrc 2g Ii:rrrlts 30 Nortlr liorrlcr lratrlt 30 Mincral Itc.sorrrrcs :rntl Iivirorunental (ie Limcstonc :rtttl l)olrlrnitc . .. . 33 (irrlnn ILLUSTRATIONS lil(;ul{Iis Page Fieurc I Loratiorr of rlrraclr;rnglc 3 () Vicws of tlrc (ircat Virllcy. 4 :,a Iixlrr.rsurcs of Iluflalo Spring limcstonc ancl clolomite in a small qurlrry abotrt two rniles soutllwcst of Campbelltown. 6 4 [xposurcs of thc Srritz Crcck PLATES Plate l. Geologic map of Palmyra Quadrangle including cross-sec- tions and environmental geology factor legend. . . . (in pocket) vii :';.- \ IY s -5, -fr q' - t$ .j '\lq :- ii- 5. t. '-.ii f. '!i -".4' { i Typical Annvil le limestone outcrop. vlll Geology, Minerol Resources ond Environmentol Geology of the Polmyro Quodrongle, lebqnon ond Douphin Cou nties by Alan R. Geyer Ilcnrrsylvania Ccologicel Survcy ABSTRACT The area described in this report is in southeastern Pennsylvania and includes parts of Dauphin and Lebanon Counties. Two major physiographic provinces are represented. A narrow belt along the southern edge of the Palmyra Quadrangle is underlain by Triassic rocks that are part of the Triassic Lowland Section of the Piedmont Province. All of the area north of the Triassic Lowland Section is included in the Great Valley Section of the Valley and Ridge Pro- vince. The Great Valley, or Lebanon Valley as it is called locally, has an average width of 10 miles and has two physiographically dis- similar parts. The southern part is underlain by limestone and dolomite and is consequently lower topographically. This section of the valley is typified by sinkholes, caves, and valley sinks but is not occupied by any one major surface stream. The northern part is underlain by less soluble shale, sandstone, and minor limestone of the Martinsburg Formation and rises about 100 feet above the lime- stone valley. Small streams following well-def ined valleys are fre- quent in this part of the Lebanon Valley. The Triassic Lowland Section has an average elevation and relief greater than that of the Lebanon Valley immediately to the north. The prominent ridges of this Section are underlain by conglo- merates, resistant sandstones, metamorphosed sediments and diabase and are for the most part densely wooded. The rocks exposed in the Palmyra Quadrangle range in age from Middle Cambrian to late Triassic. Quaternary alluvium deposits are present but are of minor importance and thickness and are not shown on the Geologic Map. The rocks are composed of shale, sandstone, limestone, arkose, conglomerate, and diabase. The first four types are the most abundant. The primary structural feature of the Cambrian and Ordovician rocks in the Lebanon Valley is a major thrusted overfold or nappe. This nappe system appears to extend about 60 miles along strike and is about 10 miles wide near the City of Lebanon. ln the area of this report the overturned fold has no appreciable regional plunge I I PALMYRA qUADRANGT,E and overall the outcrop belts are tairly regular. Interpretation of these geologic structures is important in prospecting for, and determining reserves of high-calcium limestone in the Palmyra area. Where the structure is complex, this interpretation must be based on detailed geologic mapping of surface exposures, sllpple- mented, if possible, by exploratory drilling. Accurate calculation of reserves and quarry planning depend on this structural analysis. The Annville Limestone is the only high calcium limestone pre' sent in the Palmyra area. lts maximum thickness is 250 feet and analyzes more than 96Tocalcium carbonate. The Annville limestone is currently being quarried for fluxstone, agricultural limestone, filler material, aggregate and as a stone used to enrich cement rock. Large reserves of high calcium limestone are available in this area to underground mining. This is another method by which the producer can obtain quality stone from the Annville Formation. The advantages of mining the high calcium limestone are many. Limestone, other than high calcium, and dolomite formations are numerous in the quadrangle. Long term prospects suggest that these rocks will be a continuing and increasingly important source of aggregate. The upper part of the Ontelaunee Formation may become a source of high-magnesium metallurgical-grade stone. Shales of the Martinsburg Formation have been tested and have proven to be potential sources of brick and sintered aggregate. More and more attention has been placed on high-alumina shales in Pennsylvania with particular emphases on the Martinsburg Formation. ln the Palmyra area, this shale may be a potential source because the chemical analyses show random samples to average about L9.5% AlrO'. INTRODUCTION GENERAL l,inrestone ancl clolomite, many thousancls of feet thick, sandstones, shales, conglonrerates, cliabase intrusives, :rnd recent stream deposits are exposerl within the boundaries of the Pahnyra Quadrangle. Limestone, dolomite and sh:rle are irnportant econornic mineral deposits of the area (Figure l). This report on the Palmyra Quaclrangle is one more in a series of de- tailecl geological studies in Lebanon ancl Datrphin Counties. A list of previous publishetl reports rnay be found in the Pennsylvania Geological Survey's list of geological publicati PLAICAU S )l I G / H lolcdu r I gJr Sectio /-J ll3bu in uclo ENGl AND rl. PIOVI NCE Plot $ sh o o otn o c i tio \+ I N LAIE^US PROVINCE VAI.I OGI EI,UE PIEDMONI PROVINCE PtovtNct RIDGE rRov tNcE Figure 1. Location of quadrangle TOPOC;RAPFIY Two rnajor l)hysiogral)hic provinces are reprcsented in thc Palmyra Quadrirngle. A narrow belt alons the southern cclgc of the quaclrangle is unclerl:rin by Triassic rocks that are part of the Triassic Lorvlanrl Sec- tion of thc Piethnont Province. The Triassic area is irrestrlarly hilly, with relicf of 100 to 300 feet, contrasting with the gently rolling lime- stonc valley to the north. Thc rnost promincnt hills, with ferv exceptions, mark thc outcrops of the thickest conglomcrate members. The boundary betrveen tlre Triassic locks anrl lirncstone is well m;rrkcd topographically as the lt:tsc of :t hill-slol)c over three fotrrths of the rvi To the north, the Great Valley is an area of rolling hills (Figure 2) with rvell-clevelopecl rlenclritic drainage. The tops of the hills average abour 550 feet in elevation along the northern border of the belt and about 660 feet just north of the Borough of Annville. The hilltops clecrease in elevation toward the main streams-Swatara Creek, Little Srvatara Creek, and Quittapatrilla Creek. The flood plains of the main streams represent the lowest elevations in the area, and range in width from one-tenth to one-half of a mile. rocke Triassla Sha I e Valley s 6 ,h \ i.3 Figure 2. Views of the Great Val.ley. fp the north, the Great Valley is an area of rolling hills with a well-developed drainage. The southern part of the Great Valley is a low, flat, gently roll ing I imestone valley. -I'hc soutllern part is a low, flat, gently rolling limestone valley. The lorv topog'aphic relief of this valley is clue entirely to the solubility of a thick se(luence of limestone ancl dolornite. -I'ypical physiographic features are clis:rppearing streAns, sink holes, :urcl large collapsed sink holes. A thick soil over the limestone beclrock nrakcs this valley very fertile and large l)ro.sperous farms are typical. STRA'I'ICRAI'IIY 5 I\C K NO\\ILEDGI I I T'] N'I"S T'he coopcration of all those people t'ho corttribtrtcrl ittforutatiou or helpccl in othcr rvays in the prellaration of this report is applcciate STRATIGRAPHY CAMBRIAN SYSTEI{ Buffalo Sprinrs Formation J'his fonnation consists of merlitrrn- to heavy-bedcled, finely crystalline lirnestone raneing from very-light-gray to pinkish-gray to medium-gray in color. Interbedded with the Iinrcstone is rnerlium- to heavy-bedclecl light- gray to yellowish-gray \vcathering dolornite. Shaly laminations that weather light-brown to reddish-brorvn are numerous. The base of the Bullalo Springs Formation is not exposecl. It is faulted -I'riassic against the Hammer Creek Formzrtion. f-l're top of the Btrffalo Springs Formatiotr is cxposerl at only one place in thc southeast corner of the tnapllecl area. Here, the top is rnal>pecl at thc base of tl're first tnassive, coarsely crystallinc clolomite of the overlying Snitz Creek Forma- tion. A total thickncss cannot bc detcrnrined as neithcr the base nor the tol) are cxposecl in any one alea. A rninirnurn thickness of 500 feet is estirnatecl front the rvidth of otrtcrop. f'he ltest exllosures prcsent are found in sevcral smal] abanrlonecl quarries :tbout I.B miles sourlrrvest of campllelltown (Fi.qurc 3). O) i I i, t z o FN Figure 3. Exposures of Buffalo Springl. limestone and dolomite in a smaTi IiiirViOouti[,o riites southwest of Campbell' town. i : s'I R,\'t'lcR.\PIt\ 7 : Llorrococ'lrclgrre C)rorrp ! : Srri/z Crrck l;orntaliort C)rcrlf ing tlrc llulLtlo S;llinus l;orrn;rtion is the rlolornite scquence of thc .Snitz Clcck liornuttion. '['he tl Figure 4. Exposures of the Snitz Creek dolomite along U.S. Route 322 east of Campbelltown. The dolomite is m-edium-light- gray, coarsely crystalline, oolitic and cherty. 8 I'i\I.M YRA (.)I JNDRANGI,E I t Sr I utr: ff r:r sl rnu n I; r.tr rnn I iort j "Ihc ,sr.lraclf cr.stown Fornration is a Iinrcstonc sc(lr.tcl)(.c tlrat strati6'raph- iclrlly nvcrlics tlrc .Snitz (jrcck lirlrrnatiorr. 'l'lrc fcw isollrtcd outct'o[)s I I J)rcscnr in rhc l)almyra arca arc tylriral of tlris unit;rs it is cxposc M i I I b ac h I; rtr r r tutiott The Millb;rch Formation is it thick .sequcnce of limcstonc and dolomite. In thc Palmyr;r Qrurrlranglc this lormation which i.s composcd of light- t{ray to lrinkish-gray lirnc,stone with meclium-gr;ry to dark-gray lamina- tion.s is intcrberlrlecl with pinkish-gray, fincly crystalline clolomite. The rlr.rlomitc also <'ont:rins shaly laminations. Individual becls ran!{c in thick- ncss fronr .sevenrl inches to two feet. .Stromatolites of thc cryptozoon type arc prcscnt near the top of the formation Thc top is placccl :rt tlre llasc of the first medium-gray, sanrly clolomite berl of thc overlying Richland Iiormation. A thickness calcrrlation in this qtradrangle is not possible because of tlrc cornplex fol IlichIanrI Fonnation 'I'lrc Richland Fornrirtion i.s prcdorninantly dolomite. Very few ex- J)osures of the l{ichlancl Fornration ,rre prcsent in the Palmyra Qtrad- r;rnsle. Orrtcrops of the lower part of thc formation are composed of merliunr-cl:rrk-gray to d:rrk-gray, nrcrlitrm crystalline, massive bedded clolo- rnite wlrich wc:rtlrcr light-olive to ycllowish-gray. A nrajor tlrrtrst fault has rcnroved rnuch of the lormation and no incli- cation of trtre thickness is 1>ossible. To the cast, in the Lebanon Quacl- r:rnrrlc, tlrc forrn:rtion is apllroxirnately 750 feet thick. 5lR\'lt(;R\r,il1 !) ()lu'x)\/l(it,\N sys I 1..\l Ilccknr:rnton'rr (il"orr1> -l'lrc cntirc section of thc Ortloritian titrlrott:ttes of the Lcb:rtron Vlrllcy is rc;lrc.scntcd in tlris r;rurclr:urqlc. "I'lrc nalne llcckrnantol'rt hrts llcen wirlcly rrrcrl in thc A;lpal;rchi:ur Stuter to rlesign:rtc Lon'er Orclovician carlronatc rocks. -I'hc llcekrn:ulto\{n of l}crks (-leirurt}' l\';ls clefinctl lrs it (iroup by Dr..|ohn P. Holison in l9l'r7. Hc est;rblishecl four forlnittions, Stonclrenqc, I{ickcnl>:rtlt, IlPler', urtcl ()ntcl:runee, rtlriclt lr:rve bccn ntalipt:tl tltroughout Lcblnon Corrnty. Ciurrlational (olrtn(ts exist bctlvectr tire Beeknrantor.r'n Clroup anrl the untlerly,ing (,lonococheasue (irou;r tltrough- out tlle Lebanon Valle,v, excel)t t'hcre thrrrst faulting- is plesent. Through most of tlte l,cbanorr Virllcy, the Ilecknl,urtown Cirorrp is or,erlain Lry the Itigh-calcirrnr Annvillc Limestone. Jlrc eontlct is abrrrPt :rntl rrsrrally shearerl :tncl rnay ret)rcsent a clis St one I t en ge F orr tta I ion The Stouehenqe Fornration exPosccl in the area consists of mecliurn-gray, crystalline lintestone. 'I'rvo charactcristic featrrres of this lirnestone are the tltin, dark-olive-gray colored shale lanrinae ancl thc fl;rt-pelible breccia becls. I.ocally, just north of Carnpbelltorvn, the shaly laminac are 2 to 3 inches thick antl weather in relief. Thin liecls anrl lenses o[ c;rlcarenite are conlmon. Thin berls of fossil fra{rnrbncal linrestone may also be fciund trear the top ancl the basc of thc formation. Dark-gray chert lenses, blobs, and thin stringers are found throughour the fonnation. TIte trasal contact of the Stonehengc Fornration rvith the Carnbrian sequence is concealed by a major thrust fault. The upper contact of the Stonehenge is graclational into the overlying Rickenbach Forrnation and is selectetl at the basc of the first massive, meclium-lieht-uray, dolomite bed of the Rickenbach Fornration. I{ Ili c kcnb a c h F ornt a tion 'I'he Rickenl)acll For-rn:rtion is present in only half of the rnap area, as it pinches out just southwest of Annville. Very few exposrrres are present. r Where it is exposed alonq Bachman Run and Killinger Creek, ir con- si.sts o[ rnecliurrn-rlark-gray to meclium-gray, finely crystalline dolomite. Several beds :rre nreclitrrn-dark-eray, mediurn to coarsely crystalline. f'he forrnation leaches an approxirnate rnaxirnum thickness of 200 feet in rhe tluaclrangle. This thickness may be rneasrrred along Bachman Run rvhere the fonnation is best exposed. Epler Fornmtion The Iilper Fonnation is characterized by thick bedded, strongly l:rnrinatecl, finely crystalline lirnestone interbeclded with a medium to thick beclclerl, laminated, erayish-yellorv weathering, crystalline dolomite (Iiigure 5). Light-gray to nearly white lirnestones are erbundant, particu- larly in the wester-n palt of the qu:rtlrangle. These beds have a distinct "lrinkish" al)l)earance similar to that of the Buffalo Springs Formation. Noclulal chert is present and :rbtrndant. 5 ,* r.J*r --\ :EE:.r' u'? ^. Figure 5. Limestone and dolomite beds of the Epler Formation exposed in a quarry southwest of Annville. West wall of quarry shows recumbent folds. 5TR.\TIGI{,\I'IIY ll 'I'he base of tlrc liplcr Iiolnurtion is n'r:rplred :lt tlre l)ottom o[ the first nr.rssive, metliunr-glav lintcst O tt tr: I ou nee Fornmtiort T'he Ontelattnee Forni;rtion is the )'ounsest strltdivision of the Bcckman- totvn Grorrp. T'hc basc of the trnit is pllrced at the lirst occun'ence of clark-gray cltert that is pl'csel"rt throtrshout most of the Lebanon Valley atrcl is a cotrspictrotrs rn:rrker for m:rppino. In thc Palrnyra Quadrangle, tlre cltert zonc l'eaclres rr rnaxirnurn thickness oI 24 inches. The best ex- posrrres of the r:hcrt are along the Rearling Railroad tracks rvest of Palml'1x. Ontelautlee Formation {" t,- jrt'..; -,t " Figure 6. The upper part of the Ontelaunee dolomite is best ex- posed in the south wall of the Palmyra Quarry, Bethlehem . Steel Corp., north of the Borough of Palmyaa. l2 I'r\LN{ \'I{A (.lt l.\DllANGI.I.l -I'he upper of tlre lorrnation uray be secn l)est in the south rvall l)art l of the Palnryr':r Qr-rarric.s o[ the l]ethlclrem Stcel Corp. lletween Palmyra arr Annville Limestone The Annville Linrestone overlies thc Beekmantclwn Group in this clrrarlrangle. It is a rclatively homogeneous, hish-calcium limestone for- nration. The r\nnvillc is prerlorninantly a tliick [o massive bedded, crystalline, high-calcirrm limestone, that u'cathcrs rvith smooth or fluted surfaces. Light sray to :rlnrost white colors are clominant on weathered surfiaces (Figure 7). Figure 7. Massive bedded, high-calcium limestone of the Annville "west Formation exposed of the Palmyra Quarry, Bethle' hem Steel Ccjrp. The fluted weatherFrd surface and the almost white color are characteristic of this limestone formation. S'I'RATICR,\t'IIY l3 In the area ilnmecliately w'e.st of Annville ancl in rhe quarries adjacent ro Rorrte 422, the appearance of the lirnestone is altered. The rock is l:leachecl, solt ancl friable btrt is still of high purity. The alteration of i:l I the limestone in this locality is probably clue, inclirectly, to the structural complexity of the area. The upper cont:r.ct rvith the llyerstorvn I-imestone is abrtrpt. I.ight- to white. hieh-calcium lirnestone becls are adjacetrt to clark-gray n .r{ray 1 almost black lirnestone of the il'lycrstorrn Formation. The base of the forrnation is rnarkecl by a very-light-rray to rvhite crys- I talline becl or berls rnottlecl or str-eakecl rvith meclitrm-to rneclium-clark sray. The Annville l.irnestone has :r .stratigraplric thickness of about 240 feet. Stratigrallhic ancl structural cornplexities account for an eastu'Ard thinning of the formation. Orttcrops of tlre Annville nray be founcl in tl're Palmyra quarries north of Rotrte 422 betrveen Pahnyr"a ancl Annville. This formation is quarried extensively for fltrx stone, lime, and roadstone. i\{yerstclrvn Limestone Tlte N{yerstolvn l.imestone is ryllically dark-gray, dense, thin bedded and carbonaceous. Occasionally beds of calcarenite are present near the base. Rock fragments in the soil above the limestone consist ciriefly of rounded and lllaty pieces that ring rvhen stnrck with a hammer. Dense, white vein quartz with a columnar or striated texture is commonly associ- ated with this float. T'he Myerstown f.imestone is sraclational into the more shaly Her.shey Limestone ancl in the absence of .qood exposlrres the contact is not easily defined. This formation ranges from 200 to 2110 feet in tl'rickness. Variations in thicknes.s are clue to local stnrcttrral complexities. Exposures of the lorver' fu[1'er.stown Lirnestr)ne :lre founcl in and near the north wall of all the Palmyra quaruies (Figure 8). Hershey Limestone Tl-re Hershey l-imestone is poorly exposecl in this quadrangle. Where present as float, it is dark-to very-dark-gray, impure, shaly, lirnestone. Weatherecl fragrneltts are rneclium-sray to yellolvish-gray or light-olive- gray, irntl sometimes completely leachecl of calcite. l\{ost fragments, horv- ever, have a clarker, calcat'eous core. Botl-r the fresh ancl rveatherecl rock fragments are very similar to the clark colerecl shales of the i\Iartinsbrrrg Formation. w Figure 8. Exposures of the lower part of the Myers. town limestone may be seen in the north wall (foot-wall) of the. Palymra q ua rnes. - z ro i!: Typical dark- gray, dense th in bedded Myerstown limestone is exposed along the road at the east end of the Palmyra quar- sl R.\ l'l(;R \l,lr\ r5 lilo:rt lr':rurrrcrrtr lrorrr tlrc l lclrlrcr l.irttcstt>nc ciut llc tlistitrgrrislrcd frorn tlrc IIrcrstorvrr Linrcrtr>rrc llo:rt ll1'tlreil gtc:rtcr ang-rrl:rrit1'nnrl tlre flrrt tlutt tltcv rlo ttot tittg rvltcrt stt'ttrk rvitlt:r ltanrttrer. 'l'lrcrc:u'c r)() (,nt(r()l)\ o[ tlte Hcrslrcr'[,itncstonc in tlrc qrratlrangle. (,lrlt rrl:rtiorrs lrirsc \ [lrrtinslrtu g l;ut'lturtiott ()cn aru I .\ groul) ol .rcrlirncnt;rr v rocks krrorr'rr us tlrc II:rrtinsbulg extell(ls fronr 'l'cnncs\cc rlorIlrcirst\r';rt'rl tlrrorrpilr l'crttrsl'lr:rltilr autl tltc Palnryra Qrr:rrlr;rrrglc iuto Ncrr .|crre)' :rs ir lrclt oI r':rriul>le rvi Shnle 'lhe shale of thc Illltinsllurg Iiorn)irtion hirs a var'icd charactcr (Figure 9). Some of it is sliglrtll,arenaceous, son)e of it is calcareorrs, but, b;,far, tlte greatest l)roportion o[ it is argilllrceorrs, lrre:rking clorvn into a clay soil. Sotnc of tlre shale is thin-bcddccl;rnrl po.sscsscs a tlistinct fissility. Somc is massively-llcdrletl rrncl bt'elks into irlcgrrl:rr fnrgnrents ryith a deep conchoid:rl fr:rcture. Irr rvcatherc Figure 9. Typical outcrops of - Martinsburg shale, thin-bedded and displaying a dis- tinct fissility. Out- crops are located along the road from Clear Spring to Syner. color lrorn thc unweathered cenler to the altcrecl surface. In a number of outcropr; sevcral tens of feet of section show no intercalatecl sanclstone or limestone. Intlivi Sartrlstone Thc sandstones of the Marrinsburg Forrnation range from fine-grained grayr,vacke to co:rrse-{rrained, pure qlrartz .sandstone and to coarse-grained arkosic .sandstone. Gray is the conlnlon color of tlrc fresh unweathered srrrfaccs, llut much of the rock i.s wcathered to a buff or yellowish-brown color. Prrre qrr;rrtzose sandstone rlocs not occur in the Palmyra Quad- r';rnglc but is prcscnt as an inrportant rirlgc-rnaker to the east in the Ilunker Hills soutlr of .foncston'n. Arkosic s:ur(ll'tone, lt'ith lrebbles an rrltit:). SonrC Lcrlr oI ar kosi< \itn(l\t{)Ilc lrrc nr:rrrive :rlttl rc:tt lt tlrickrtcsrcr ol'tcn Lo trt'clrc lcct. \\Ilrcrc cxlx)\c(l irr lriqlrrvr)'cut\ it is ttrtt:rlli'liglrt l,rrorvlr in tolor rrn O rtrtelrttrt rrute (Jon.qlonrcr:rtc in thc I.[:tltinslrtrrg l;orrnrrtion consists oI nvo t)'pcs: a sh:rlc-s;rn Lime.stone L'he linrestoncs of the Nlaltiusllurg Form;rtion con$ist of tltree lithologit: ty1rcs: (l) interbeclde Figure 10. A small quarry in Martinsburg limestone is located along the road-leading from Quittapahilla Creek north- east to Fairview School. larger of the two quarries is located in the corner of the road paralleling Quittapahilla Clreck an 'fftirAness Unit (Fcct) I Interbcddecl limcstotrc and shalc, dark-bluc'gray to black rr'ith otrc lirncst 3 Black limcstonc itr bctls which .rangc irr thickncss fronr /2" to 3'. Tlrickcr llctls tetttl to bc lamirlatccl atrd con- tain numcrous calcitc vcins. Ncar bottottr of scqucnce tlre coarsc laycrs arc brt'ccia rvith allgttlar fragmcnts of lirnc.stotrc /8" to l" tlrjck an Another quarry occurs south of Bellegrove where al)out 20 feet of inter- bedded limestone ancl shale are exl)osed. The limestone layers range in thickness from two to three inches with nvo beds alrnost two feet thick near the base of the quarry. Representative sl)ecimens of each of the limestone types have been analyzed for insoluble residue by the late Dr. X,Ioseley. The amount of insoluble residues ranges frorn ll.5% to 46.3f" with an average of 26 analyses being 24.070. Estimates of the percentages of coarse and fine residrres gives an average of about 609/0 sancl ancl silt and 401" clay. The coarse sand fractions rvere found to contain zircon, feldspar, pyrite, garnet, mllscovite and tourmaline in aclclition to qu:lrtz. In one sample of the residtre ancl in a polished section frorn the same outcrop, frag- rnents of fossils were observecl. PRE-TRIAS.SIC ROCKS OF UNCERTAIN AGE I\'fill Hill Slate At one locality in the sotrtheast corner of the Palmyra Quadrangle is a r rock formation desisnate the "i\r[ill Hill Slare". It is a hard, light-gray to i black, banded hornfels. The hornfels is frequently laminatecl and rich 20 I,ALMYRA ()IIADRANGLE in cal'ltonilte or calr;i-silicatc minerals. Altcrnating bands are usually . silica-poor :rnrl silic:r-rich but arc sometimes calcium-poor and calcium- rich. The tlrin laminac are rclics of :rn original variecl composition. r\t solne localitics, prim:rry cross-betltlinE; structrlres ltave been preserved. Tlris rock unit is of dotrbtful age and origin. It is seen only in the contact zone of the inrusive diabase. The corrclation of the Mill Hill Slate cilnnot be solverl structrtrally becatrse it is in fault contact with the Iluflalo Springs Formation which itself is overturned. Therefore, the only Jrossible correl:rtion nlust be bascrl on lithologic similarities. The original formation al)pears to have been a laminated, in part conglomer':rtic, limy shale. No other trnit in the immediate vicinity fits this rlescription btrt certain limy I)arts of the Martinsburg shale or Hershey Limestone most closely resemble it. Furthcr stucly is neeclecl to solve the intriguing problem of the exact age and oriein of this rock unit. TRIASSIC SYSTEN,{ Hammer Creek Formation The Hammer Creek Formation consists of interbedded red shales, red, brown, and gray sanrlstones, and fine to coarse quartz conglomerates. Rec[ shale is thin-to merlium-beclded, usually friable, and has a hackly fracture. The thin-beclded variety usually has wavy or uneven bedding planes. Ri;rJrle marks antl mudcracks al'e present. The shales are usually non-rnicaceous and nearly always interbcdclccl with siltstone and fine- grainecl sandstone. Sanrlstone is the rnost widespreacl rock and is the dominant component in much of the area (Figure I l). In color, the sandstones range from red through brorvn to light-gray. The red and brown sandstones are the most common. Rc t+ Figure 11. Typical sandstone outcrops in the Hammer Creek - Fbrmation. Outcrops are located along the road from Campbelltown to Plainville. Pebbles up to two or tlrree inches in cliameter occur in the most prominenr conglomerate member which forms the 900-foot hi,gh hill at the east edge of the qlr:tdrangle. In rnost of the other conglomerate members the pebbles usually clo not exceecl an inch in diameter. Bands ancl lenses of large pebbles alternate with becls containing smzr,ller pebbles, or with beds of sandstone with few or no pebbles. Occasional beds have pebbles almost touching with only enough groundmass to fill the inter- stices. IVlore comrnonly the groundmass forms much more than 50 per cent of the rock. The conglomerates grade into pebbly s:rndstone, rvith a decrease in the amotrnt and size of pebbles. The groundmass of the conglomerate which" is essentially that of the coarser szrnclstones consists chiefly of angular to subround grains of quartz, tiny grains of quartzite, and occa- sionally fine sandstone and other rocks, bound together by u matrix lii (,t 22 I',\l \r\ lt \ .\t)t{.\\(;l.I: i ol r l.rr rrrirrcr':rls f)iabase [.urge antl snrall intrrrsivc borlies ol STRUCTURE (;lii\,1l..RAL 'l'hc Jrrincilrlc stru<.trrral fcaturc of thc (jamtrrian rrncl C)rtlovicizrn rocks irr thc l.eb;rnon V:rlley is a nr:rjor tlrrtrstcrl ovcrfold rlr nappc. Sinrilar l'l;rl)l)cs lr:rvc bccn recognizc :, NS I -*t-: ::i-i._.^*_ )* .*: I ooo' Seo Level Oo looo' 20oo' eooo' SC ALE Approx. 3 miles Figure 12. Generalized diagram of the Lebanon Valley nappe fu{inor fol (;RI._.\'t' \' \t,1,1..\' sr.(, I l()N lrolrlr 'l'lrc gcolo!ir rrr,rlr ol tlrc l';rlrrrrr;r (.)tr;rrlt;rntlle sltorls tltc xcttct;rl tlilr of tlrc <:rt'lrr.rn;ttc\;rrtrl rlr,rlcs to lrt: rorrtlr<:;rstu';rttl rr'itlr lrt-()gtcrrirt'11 rllrlcr fi.rt'rrratiorrs cxl)osctl tr-, tlrc sr.rtrtlrc:rsl . 'l'lrc r ()ti( ltt\i()tt ir tlrtrt tlrc' cttl irc ro(k \c{lucn(c i: orcr trrtrrcrl. II:rrr\ ()ut(l(rl)\ irt tlrc tn;r1r1rctl ;ttc;t (lo ll()t slr N s -\ SCALE ----nt .r/ 400 Ft /// t \_, / n/ ,/ A /t--/ / A B B \ C c p.a. 'oi Fisure 13. Detailed cross-sections through the quarrie-s immedi' ately west of the Borough _of Annville. Taken from Penn' sylv-ania Geologic Survey Progress Report 140. S"IRUCTURF] 27 ,--*fi- * s__.x." ,f .-q $ . *i '.- t. i)fi*'' $-- Figure 14. Complex folding of limestone s and dolomites in the Epler Formation. Small quarry located on the southeast side of the Borough of Annville Faults The largest fault rvithin the carlronate rocks is the South Lebanon T'hnrst Fault. This thrust rn:ry be traced from thc Lebanon-Berks Co. line to its intcrsection rvith the Triassic border southeast of I{umrnels- torvn in Daul>hin County. In the Palrnyra quadranglc, much of the Conocheaeue Groull plus some of the Stonehenge and Buffalo Springs Formations are missine. It has been calculated that the minimum of sevct'al miles disl:lacenrcnt exists. Faults are common in the Martinsbrug Formation. In the at-ca betrvcen Uuion lVatcr Works ancl Rellegrove, Iitnestone belts eucl abruptly at a line which is almost north-south (l\{oseley, 1954). A bclt of red shnlc rnakins up the top of a flat hill at this locality also encls at the same line. Strike-slip rnovement along this fault might bc in tl're orcler of four-fifths of a mile. Abotrt nvo and tlrree-quarters miles northr,vest of Annville, a prominent hill rises abrtrptly from the flood plain of Quittapahilla Creek. The hill is composed of recl shale, greenish-gray quarrzite, and interbcdded argil- laceous sandstone antl shale of thc Martinsburg Formation in a tightly t 28 PAI,MYRA QUADRANCT,E itl jit Figure 15. Recumbent folds in the Fplqr Formation. Small qua.rry is , located approximately 1500 feet east of the quarry shown in Figure 14. foldecl syncline. The hill ancl the syncline end just south of the westward- flowing tributary of Quittapahilla Creek. This abnrpt cut-off is inter- pretcd as a cross-fault which strikes ezrst-west, almost perpendicular to the axis of the syncline. The rocks of the syncline are apparently scparared by a cross-fault on the east from adjacent limestone and shale. The limestone in turn is cutoff by a cross-fault so that it abuts Martinsburg red shale to the south, The eviclence for their existence is the areal distribution of the blocks of rock and the offset ridges. The faults are interpretecl as high angle dip cross-faul ts. Moseley's manuscript maps of the Martinsburg Formation in Lebanon County show a clistinct textural break and a lithologic change occttrring approximately throueh the middle of the Martinsburg belt. Highly dis- tortecl structures in the Martinsburg occur south of this line. This break is also on strike with a thrtrst fault mapped in eastern Dauphin Cotrnty by Carswell and Hollowell (196S). It is this major break that is t , s'rRUc'ruRE, 29 interpreterl as the Yellorv Rreeches 'I'hrrrst by Maclachlan (1967). A complete :rnalysis of this thrrrst zone is sir.en by il{acl:rchlatr (1967). A snrall lnrtion of this tlrnrst zone :rpl)eal's to be present in thc Itortltwest ' corner of the Palmyra Quadrangle. .I-RIASSIC LOWLAND SECTION -I"riassic The resional structure o[ the rocks can be clesc;ribetl as a homocline lvith moclerately steep northrvar(l to northwesterly clilis, in- tersectecl by farrlts uncl lo<:all1,u'arpecl to lorm open anticlines aucl syn- , clines. In the Palmyra Quaclranule, an anticlinc auct a sytrcline are super- imposed orl thc north-rlipping homocline. X{inor cross-faults offset some of the conglonterate mernbels. Faults occul' along the north mar.gin, btrt : their clisplacenlent is believerl to be small. Fokls Colcbrooh Anticline -l'he curved strike of cong^lornel':lte members in the sorrtlleastern corner of the qtraclranrlc inclicates a lilunging anticline rvith an axis striking nearly cltre nortll-soutll tlrrotrsh (iolebrook in the Elizabethtorvn Qua Pluittuille Syncline Sotrtheast of Carnlibelltorvn, the rocks a IIinot'faults rvitlr :r north-soutlr tlenrl ctrt tlte Tt'i:rssic rocks soutlt of 1 ,\[orrnt I)lcas:rr-rt:rrrcl soutlr o[ (iilr-ficlrl S 1,rla< r:s ;rlottg tlrc tt":rr cs of tlre [aLrlts. Sorrthn'est o[ (i:rrnplrcllton'n tu:o f:rrrlts rvitlr a northwest strike tli.sJrlace tlrc 'I'ri:rssir lrorrln^. J'lre eastern onr: oflscts tlte Tri:rssic margin abottt one-lralf rnilc,:rttcstin{I eithcr tcl l:rrge tlislrlrrcertrcnt or more probably to -Ihis a gcl)tly slopinu floor bcnr:atll that lrrrrt of the'l-ria.ssic basin. fault Also trrrn<::rtes rli:rb:rse Tltr: Fault At 7'hr: North l4arsin Florr tlre e:rsteni erlsc oI thc rluaclranglc to a lnint south of Carnpbell- town, tlie north borcler of the Tliassic is [airly struight excel)t for a [atrlt oflsct sorrth o[ trlorrnt Pleas:rnt. 'I-hc straightness may sussest an itn- I)ort:rnt [arrlt, rrnrl tlic fact thut thc l:ortlcr trrrr]c:rtes thc northward- plunginu (lolcllrook anticlinc .supports such an interpretation. Appre- : nriln)'tltottsrrrrls o[ fcct slroulrl no[ l)c assi5;nerl to this nortlt-rnar-gin fatrlt rvithout :r MINERAT RESOURCES AND ENVIRONMENTAL GEOLOGY I.IIGH-CAL(]I U il LI}TES"I'ONE -79 D : "*ll It, "r u' ;* ;\' i: .' t-.,r..!, t ., .*r- .. I t 'l , ,rl*g '*.;.*-o.f Figure 16. The Annville limestone underground mine northeast of Hershey and immediately west of The Palmyra quarry. View sliows .openings and supporting pillars of room- and-pillar mine. ; 32 I,ALlrYr.A Or.:ADRA.\-cl.E i j The Annvillc l-imcsronc is thc only high calcium limestonc present i! in thc P;rlrnyra (]ulrrlranule. 'I-lris forrn:rtion re;rcltcs a maximtrrn tlrick- ij ness of :rpl)roxint:rtcly 250 I'cct in thc :rrca, Analyscs of tlrc limestone'i indic;rtc tlrat tlre Annvillc herc averurge.$ morc than 96('/o t:alcium car- bcrnatc. SIril-rrncnts of largcr sizc stonc r:ommonly tcst over 97!,, c.alcium'i carl>olratc 'l'he Annville Lirncstonc is <:urrcntly bcing quarried for fluxstone, I agrictrltur:rl limcstone, filler matcrial, a!{gret{at(f, ro:tdstonc, railroad l hallast, and as a stone tlr:rt i.s uscrl to cnrirlr cerncnt rock. (ihernical i analyses oI tlrc Annville satisly thc rerltriremcnts {or ccmcnt limestonc, fluxstone, agriculttrral limestone, and in sonre cases general chemical , uses, filler, ernd Iime. No attcml)t has bcerr nr;rclc t{) calcul;rtc tlrc reserves of high calc'ium Iinrcstone in this cluaclranglc. Rcrovcrablc rcsen,es may bc aflected by: many lactors, such as lo<;rl areas of exccssive overllurtlcn, grouncl water' an<[ cultur:rl fc:rtures*rrrlr:rn antl .suburban rleveloprnent, railroacls, and higlrw;tys. L:rrge aclclitional rescrves of high calcium limestone woultl be availahle in tlris zrrea to rrndergrouncl rnirting. Untlcrground nrirring (Irigurc l6) is a metltorl by which tlre lrigh c:alcium lirnestone protlucer ran obtain quality stone from the Annville Forrnation. Minin;r ol' this limcstone has, to date, not bcen widely used , in tlte l,cbanon Valley. However, tlte atlvantages of mining the high r:ak:ium Iirnestone are many. l. Mining eliminates the removal of overlrur 2. A clean stonc ;lro l)ortant ber;rtrse tlrc frrttn l:rurl oI tlre Vallel'oltcn rells for nt()t'e tllltrl a 5l(XX) :rn :rcre. 5. I.'inclinc av:rilable bp;rce for srrrf:rce stor:rse of the limestnne is some- times a problcm, but in mining this llroblem can be .solved by storine the limestone trntleru'ouncl in an untrserl portion oI the ttrine. 'l'he size o[ tlrc lriglr ralcitrnr liurestonc cleposit is a b;rsir retlrtirement that nrust be nret bclore rnining' oI srrc.h a rleposit bccornes fc:r.rible. Forttrnatcly, tlris rlcposit iu tlrc I):rluryra Qulclranglc is :r tlrick one (g^relrter than 2(X) l'ect) rrnd rvith extcnsive trnclerurouncl clevelc)l)nrent tlris miglrt conrpcte succcsslully rvith any of tlre c1u:rrry operations to the east. 1'he clip oI thc deposit is :rnt.rtlrer le:rture to consicler in clctet'minins whctlrer or rrot nrining is fea.sible. trlining of incline I.IN,{ESTONE AND DOI,ON,IITE Less pure limestone :rnrl dolomite formations are numelous in the quadral'rele. One of the lirnestone formations ancl one clolornite forma- tion are ecnnomic:rlly imltortant. 34 P,\LtrIYRr\ QTIADRANCLE The Epler Iiornration is a thick ancl continuous litnestone and dolo- nritc unit that occurs across the qtradrangle. This unit has been a rnajor source of crushecl aeei'egate. It is presently rluarried for tl'ris ptrrposc at Palrnyr:r ancl to the rvest at Steelton. Strbstantial reserves of this forma- tion exist ancl shoulcl lle cornparable to that being actively procluced. These reserves cotrlcl be macle available if clenrand warrantecl. Long term prospects sugsest tlurt the EPler Formation will be a continuing and in- creasinaly important source of aggregate. Urban expansion in the l,ebanon Valley shoulcl provide this clemancl. The C)ntelaunee l'ormation is more clolomitic than the Epler and it nray yielcl a tougher, lllore clesirable aggregate. To the lvest, several quar- ries are proclucing :rggregatc fror.n thc forrnation. The upper 200 feet of the C)ntelaunee Fonnation has a potential v:rlue as a hieh-quality rnag nesiam stone. T-his part of the forrnation may become, in the future, a source of high-nursnesiurn nretalltrrgical-srade stone increasinsly sought by the steel inclustry. GITOTJND WATEIT Carbonate Rocks A very cletailed grouncl $':lter stucly rvas conclucted in this area in 1963 by Harokl N.Ieisler of the IJ. S. Geoloeical Survey. An inventory of nrtrnicipal, incltrstrial, ancl domestic wells ancl springs rvas tnade during this investigation. Short ten.n ptrmping tests at low pumping rates were made to cletenrrine the relative specific capacities of the u'ells. In addi tion, grounclrvater samples rvere collectetl ancl comJrlete chemical analyses, of the s:rrnples lvere rnade. All of the information is ptrblishecl in Ground' Water Report l8 of ttre Bure:rtr of Topograplric ancl Geologic Strrvey. Tlre follor,vine conclusions are those derived by N{eisler (1963) for this qtrarlransle ancl the adjacent quadraneles to the east: l. "fhe most reliable sources of grouncl rvater are the Shafferstorvn and tr{illl;ach Forrnations of the Conococheagtre Grotrp, ancl the Stone- hengc ancl Ontelaunee Forruations of the Beekm:lntown Grotrp, and the Annville Limcstone. ?. The least leliablc sources of grouncl water are the Snitz Creek For- rnation of the Conocochcague Grorrp, the Epler Fonnation of the Beekmantown Gtoup, ancl the Hershey Lirncstone. 3. Thc non-shaly lirnestone acluifers generally yield larser strpplies of water to lvells than clo the clolomite aqrrifers. 4. The nraximurn porosity o[ the carbonate rocks occurs at son]e dis- t;lnce below the rvater table. I{cportcrl clepths to waterbearing crevices in thc l.ebanon Valley range forrn ]6 to 505 feet. Scventy-five percent I l\l I N tr R'\ l- R ESO {-l RCI..S-E N 1' I RON }l [.NTA I- G L.()I"OG\' J) of tlre \viltcr bcaling crcviccs lvcrc encountered at lcss thatr l4ir fcct. The rnaxirntrrn conccntration o[ lr:lter bcaring creviccs an(1, ltettcc, rnaxirnurn lrorosity is benvecn 70 ancl 80 fcct trelorr' the lantl surfacc. 5. Grclrncl rv:tter in the carbonate rocks is of the calciuut lricarbonate tyJ>e. Nitrate contarnination is cornmon ancl man)' sarnplcs takcn in this recent strrcll' containecl mol'e than .l5 plinr nitrate, $'hich is thc rn:rxirnurn nitt'ate content consiclerecl acceptable b1' thc U. S. Pul>lic Health Selvice. r\n east-rvest tr-enrling llelt, allproximittely onc nrilc north antl one nrilc scltrth of Rorrtc .l22, shorvs a significant nirate con- tamination. This nitratc contallrination is prol>ably the rcsult of con- tamination frorn urban :rncl inclustrial u'aste The groundrvatel l)otcntial for each carlxrnate formation is trivert in the cxplanatiolt to the Geologic trIap, Platc l. The ltigh ptrritl' of tlre Annville Lirlestone rnakes it particularly stts- ceptible to the formation of laree solution cavities rvhir:h in turn makes it one of thc leacling aquifers of tlre arca. In rnining, ho\r'evel', this groundrvzrter has been :r rnajor prolllenr. Almost every large c;rrarry in the Annvillc llclt of l,etranon and l)auphin Cjotrnties has to co;>c rvith extrentcly larsc quantities of u'atcr. In somc cascs punr;ring costs becorne excessive. In the unrlerslounrl nrining oI this high calcitrnr limcstone, this problenr is er/en more accute. llefore minins operatiorls al'e begun, qlrarry oper:ltol's must seek an effective c oil ond unconso/idoled Pi n nocles mo terio / Sur foce rch Opening Limestone or dolomile b edroch Debris, moslly roct Figure 17. Hypothetical cross section through sink hole f-he sketch shows pinnacle or jaggecl ancl rough wearherins as opposecl to a smooth surface on top of the bedrock. When rhe overlying soii ana ttnconsoliclated material dry-out, clolvnrvarcl misration of soil debris into solution cavities takes place. The arch over the solution opening tends to rnisrate uplvard as material graclually falls into rhe op.rrirrg. clttapse Inay occur lvhen trnusually heavy loacl conclitions exist over the arch causing the arclt to break. A heavy rainstorm that saturates the soil and rveakens the arch lrlay act as the trigger for the collapse. A catastrophic type of collapse can occur abo'e the areas of pinnacle or jagged bedrock whereas qeneral a subsiclence is likely ou.. ,ir.us of a smooth surfacecl beclrock. Sinkholes of the catastrophic type are usually sreep or verrically r'valled and may ranse from E to r0 feet to an excess or tooieet deep. . Areas in daneer of collapse by sinkhole clevelopmenr are extremely imllortant in consiclering the foundation requirements for highrvays, dams, bridges :rncl high-rise builctings. As thc popularion increases and sltifts to sttburban cli.sricts, more and more of the carbonate beclrock area in the Palmyra Ouaclranele ancl elservhere in Pennsylvania lvill be the site of extensive roacl btrilding, inclustrial clevelopment ancl private housing expansion. It is irnportant to be aware of rhe potential hazards present in these carbonate rocks in orcler that proper iesting and plan_ ning n'ill prececle construction. iltI N ERAL R ESOIJ RCtrS.E,N \/I ROJ\i M ENTAL CI|OLOGY 37 M artin sb ttr g Ii or m a t i ort A tletailed grouncl rvater sttrcly of the N,fartinsburg Formation rvits completed anrl published in 1968 for an area immecliately rvest of the Palmyra Qtraclranglc. 'I'he rock types stucliecl in the N{artinsbutg For- mation were chiel'ly shales and shaly siltstones. N{inor types inclucted siliceous shales, thin beclrlecl shaly limestones, limestone conglonlerates, clayey clolomites, sandstones, ancl erayrvackes. Carswell ancl Hollorvell (1968) founcl in their study of the il{:rrtinsburg Formation the follorving: l. The upland stream valleys are the most favorable topographic loca- tinns for obtaining the highest-yielding wells. Grotrncl lvater is storecl ancl moves throush these rocks in openings along joints, faults, ancl bedding planes. 2. As clepth increases, fracture openings in the il{artinsbtrrs rocks clecrease in number and size. i\{ost rvells yielcl }vater from zones that are less than 200 teet cleep. 3. Well development by adding a cl"remical cleaner (chiefly hexameta- lthosphate) ancl strrging proved to be an eflective tool for increasine well yielcls. Simple rvcll clevelopurent by surging ancl bailing im- proved a u'ell as much as 67orto and by aclding a chemical cleaner arrd surging, a rvell rvas irnproved an aclditi<>nal 401n. 4. North of the Yellow Breeches Thnrsr Fault, yielcls of l0 to 50 gpm are common. 5. Soutli of this fault, rvells comnronly yield I0 gpm or less. In this are:r, the highest yielcling rvells (50 to 200 gpm) are in rhe lime- stones of the l{artinsbtrrs. The concltrsions reaclted by Carsrvell and Hollorvell (1968) for the Martinsbttrg Formation in Dauphin County apl)ear to tre valid for the Palmyra Qtraclranele. Hantnter Creek Forntaliott 'fhe Harnmer Creek Iionnation consists lrrimarily of fine- to coarse- grainecl quartzose sandstone ancl red shale rvith interbeclcled quartz pebble congleimerate in the Pahnyra Quadrangle. No cletailecl grotrncl water studies have been macte of this forrlation but generalities concern- ing it are obtainecl [rorn the data r:ollectecl try Seaber ancl Hollyday (1965) for tlre f,ower Susquehanna River Basin. l. Nlost rvells in this formation range in yield from b5 to 480 gprn. Fifty percent of all the successful rvells inventoriecl yielclecl 160 gl)nr or more. ,l ; i 3B [,AI.\' \'R,\ ()I',\I)R,\\CI-E 1r : 2. \[axirrrrrnr vickls nr:rv bc lcalizcrl ft'orn rvclls clrilletl to 400 feet cleep ancl l(l inrlrc.s irt 'I"rvo positivc stcps t()rv;u'(l tlrc s SHAI.E E:rrl1 in I 1|(i2, iur esrig-:rti<.rn into tlre prolrerty' :urtl uses of Pennsl'l- r':rnil's slr:rles ;rn Sarnple Nurnbcr 1 57-6-1 A 7,,'r' Quadrangle: Hunrrttelstou'tt 1 5'; Palrrrvra 7 Location: Exposurc alourl thc c:rst siclc of Statc ltclutc 934 about 0.8 rnile northrvcst o[ Annvillc. Geologic Unit: Ilartinsburg Forrnatiort, Orclovician Agc Description: Palc-red-purplc shalcs rvith sornc becls o[ grccnish-grav s]rales, nrcasuring sixty stratiqraphic fcct, are cxposccl along thc roadrvay fronr 7f) to 130 lcct north of telcphonc polc \1I] ICi 5781. Thc hcieht of the cxposure in this scction is frorn 2 to 2f) fcct. Attitudc of Bcdding: N80\\I; 84\ Sarrrpled Irrtcrval: Cornpc-rsitc sanrple rcprcscnting 60 stratigraphic fcet of scction. Typ. of il,laterial: shalc Chcrnical Analysis: .\lincraloqr' : N-ray' : a Accuracl' (*) SiOr 60. LlO Quartz 32 8 Al.rOr 19.70 IIica 47 8 FerOl 5.97 Kaolinite I 6 FeO 2.46 C-V-I1o 4 3 CaO .07 F t'ldspar 0 3 lvfgO .98 KrO 5 .00 ()thcr Tcsts: Na2O .52 Tior .82 pl l: 7 .t) L.O.I. 4.41 \Vorkability: not plastic, short anrl rncaly' ( S .004 \vater of plasticity it 17.0 CO, .26 'i Drying shrinkage: 1.0 cornb. II"O 4 ."15 Dry strength: lorv 40 PALMYRA (2(JADRANGLE Slow-Firing Tests Approx ()/e Tcnrp. "F Color Hardness tf,Shk. Absorb. ,Sp. Gr r 800 Sandy brown Soft, crumbly 1.0 14.3 2.75 r 900 Sandy brown Soft, crurnbly r.0 12.6 2.73 2040 Brown Fairly hard 2.5 9.9 2.70 2100 Dk. Brown l-Iard 2.5 8.0 2.69 2200 Cray black Stccl hard 2.5 5.8 2.59 2300 Mclted and cxpandcd Bloating Tcst: Slight Potcntial Uses: Possibly brick and sintercd aggregate. Sarnple Nurnber r57 -6-18 rAl Quadranglc: Hurrunelstown 1 5'; Palnryra T Location: Exposure along the east side of State Route 934 about 0.8 mile northwest of Annville. Gcologic Unit: Martinsburg Fornration, Ordovician Age I)escription: Sixty stratigraphic feet of gray-red and purple shales are ex- posed south of telephone pole rnarked ME K 5783. This section represents the northern portion of an exposure which extends for a distance of over 550 feet along the roadway. Attitude of Bedding: N80W; 84N Sarnpled Interval: Cornposite sample from sixty stratigraphic feet of section. Type of Material: shale Chemical Analysis: Mineralogy: X-ray: t.) / /o % Accuracy (*) ,SiOr 62.50 Quartz 32 8 Al20' tt .05 Mica 51 8 Fe:rO.r 5.38 Kaolinite 0 J FeO 1.77 C-V-Mo 3 2 CaO .11 Feldspar 1 2 Meo 1.34 K.rO 6.00 Other Tests: Na2O .26 TiOr .95 pl-I:7.8 L.O.I. 4 .58 Workability: not plastic, short and mealy s .008 Water of plasticity a/62 19.O COr .JJ 0/e Drying shrinkage : 1.0 cornb. FI:O 4.25 Dry strength: low I\t I N I.- R A l . R t-so tJ RCF-.s- tiN \j I R()N I\l LNTA I- C EOLfi;Y 4l Slow-F'iring Tcsts: APProx' Temp. "F Clolor llar 1 800 Dk. bufl brown Soft, crurnbly 1.0 l7 .2 2.67 I 900 Dk. l:uff l;rown Soft, crurnbly 1q 13.8 2.61 2000 I)k. brown Fairly hard 5.0 8.3 2.59 2100 Dk. Ilrown l Iard 7.5 4.9 2.54 2200 Dk. llrown Steel hard E*p 2300 Melted and expanded Bloating Tcst: Slight Potential Uses: Possibly brick and sintercd aggrcgate. Sanrplc Nunrbcr 157-6-1C rA' Quadrangle: Hurnrnelstown 1 5'; Palmyra 7 Location: Exposure along the east side of State Route 934 about 0.8 nrile northwest of Annvillc. Geologic Unit: Martinsburg Fornlation, Ordovician Age I)escription: Forty stratigraphic feet of nroderatc-ycllow-brown and gray- orange, thin-bcdded shales arc cxposed to the south of a point about 60 feet south of telephonc polc markcd ME K 5783. The hcight of the exposure is about 10 feet. Attitude of Cleavage : N65E; 45S Sanrpled Interval: Cornpositc sarnplc takcn frorn forty stratigraphic feet. Type of Matcrial: shalc Cherriical Analysis: Mincralogy: X-ray: (t/ o/ ,/(J /o Accuracy (*) sio2 61.40 Quartz 34 8 q') AlzOa 17.30 Mica 1 0 FexO3 6.42 Kaolinite 1 3 FeO I .44 C-V-Mo 3 3 CaO .72 Fe ldspar I 3 Mso 7 .t9 KrO 5.10 Other Tests: NarO .55 TiOr .88 pH: 7.7 L.O.I. 5.53 Workability: not very plastic, short and S .01 me aly COz .40 Water of plasticity c/s: 22.0 comb. HzO 4.76 7o Dry shrinkage : 3.5 HzO @ t20oc .37 Dry strength: low 42 PT\Ltr,TYRi\ QUT\DRANGLE Slow-Firirlg Tests: Approx. oF. Temp. Color Hardness % Shk. /6 Absorb. Sp. Gr. 1800 Dk. buff brown Soft, crumbly 5.0 19.7 2.71 1 900 Dk. buff brown Soft, crumbly 6.0 16.2 2.69 2000 Dk. brown Fairly hard 10.0 8.3 2.61 2100 Dk. brown Hard 1t .0 5.2 2.58 2200 Very clk. brown Steel harcl 1l .0 2.8 2.48 2300 Gray black Steel harcl E*p Bloating Test: Positive Bloating Tcsts (Quick-Firing) : Crushing characteristics: Good Particle size: *LA + r/4' Dryingcharactcristics: Good Retention tirne: 15 Min. T'enrp. oF. Bulk Density Lb/Ft3 /6 Absorb Remarks 1 900 ?.26 140.8 5.0 No bloating 2000 2.44 152.0 2.3 < No bloating 2100 2.09 730.2 2.6 Slight bloating 2200 1 .30 81 .0 3.0 Fair bloating Evaluation: Poor rcsults nrav be due to the anrount of wcathered shale in the sarnplc. Potential Uscs: I'ossibly brick. Sarnple Number 157 -6-2 Quadranglc: Hunrrnclstown 1 5'; Palrnyra 7yz' Location: Exposure along the east side of State Route 934 ncar the southern boundary of Bellcgrovc, about 2.7 rnilcs northwcst of Annville. Gcologic LJnit: lrlartinsburg Forrnation, Ordoviciarr Age Description: l\4odcratcly wcathercd shales of the Martinsburg Fonrration arc cxposcd in a roadc.ut for a distance of about 200 feet. Thc colors of thc shale range frorrr light olivc gray to yellow gray. Attitudc of Bedding: Strikc approxirriately EW, dips steeply south Sanrplcd lnterval; florrtpositc sarrrple frotn cntirc exposurc Typ" of Nlatcrial: shalc g III I N RA I, R f, SO U RCI.:S.E N VI RO ;r. ITI f,,NTA L CEO LOG Y 43 enlical Analysis Mincralogy: X-ray ct IL /O Accuracy (+) SiOz 57 .50 Quartz 33 8 AlrOr 19.60 fulica 45 8 Fe.rOr 7 .23 Kaolinite I 3 FeO 1.77 C-V-Mo t2 5 CaO .19 Feldspar 0 3 Mgo 1.20 KrO 4 .08 Other Tests: Na2O .43 TiOr 1 .02 pH: 7.4 L.O.L 6.94 Workability: not plastic, short and rnealy S .014 Water of plasticity /6: 24.0 COr .55 (,i Drying shrinkage: 1.0 cornb. I,IrO 6.39 Dry strcngth: low Slow-Firing Tests Approx. oF Temp. Color Hardness tl Skh. /6 Absorb. Sp. Gr. r 800 Dk. buff brown Soft, crumtrly 4.0 21.8 2.76 I 900 Dk. buff brown Soft, crurnbly 4.0 r9.I 2.73 2000 Med. brown Fairly hard 7.5 l2.o 2.62 2100 Dk. brown Hard 8.0 10.4 2.62 2200 Dk. brown Very hard 8.0 7.4 2.55 2300 Gray black Steel hard F)xp. Bloating Test: Negativc Potential IJses: Possibly brick. Sanrple Nunrber 157 -6-3 Quadrangle: Hummclstown 15'; Indiantown Gap 7/2' Location: Exposure along thc east side of State l{ighway 934 about 4.3 rniles llorthwest of Arrnville. Geolclgic Unit: IVlartinsburg Fonnatiorr, Ordovician Age Description: Grayish-rcd to nloderatc-rcd sl"rale, nruch of lvhich has wcath- cred grayish-orangc, is exposed for a distance of several hundrcd fcet along the roadcut. The hcight of the exposurc is from six to seven fcet Attitudc of Bcdding: N45E; 40SE Sanrpled Interval: Conrpositc sarnplc from southcm half of thc exposurc. Type of lvlatcrial: shale 44 PALMYRA QUADRANCLE Chernical Analysis: Mineralogy: X-ray d CV /o /o Accuracy (*) SiOz 57.00 Quartz 40 10 Al2o3 20.94 Mica 44 10 FerOr 8.01 Kaolinite 1 3 FeO 1 .04 C-V-Mo 3 2 CaO .12 Feldspar 1 3 Mgo ,93 KrO 4. 10 NazO .83 Other Tests: rior .92 L.O.r. 6.08 p}l: 7.2 S .01 Workability: not very plastic, short COt .26 Water of plasticity 7o: 20.0 comb. I-I2O 4.97 c/p Drying shrinkage : 1.5 HrO @ 120"C .85 Dry strength; average Slow-Firing Tests: Approx. Temp. "F Color Hardness % Shk. /6 Absorb. Sp. Gr. 1800 Dk. buff brown Soft, crurnbly 3.5 18.0 2.75 1900 Dk. buff brown Soft, crumbly 5.0 14.6 2.73 SELL,C'I'ED REITERENCES 45 In 1908, Spencer postulate(l that the ore should persist in depth ancl shoulcl :rlso occtrr at other points along this fault both east antl west of the olcl mine. Flowever, in 1957 the Pennsylvania Geological Survey in cooperation rvith the U. S. Geological Sun,ey flerv:rn aeromagnetic srlrvey of this area (Bromery, l96l) and failecl to fincl any anomaly in the vicinity other than that exhibited by the diabase itself. 'I'tris rvnuld tend to eliminate the possibility of a large ore body buried ar deprh, depending to some extent on the orientation of the remanent magnetization. From the fiekl relationships, the simplest interpretation of tlte margin- parallel fatrlt is that it transects sheet clirtbzise and is the fault intnrded by ore (see Spencer, 1908). If these interpret:rtions are colrect, the time of ore introcltrction is separatecl from that of cliabase injection by one or more periods of faulting, sirnilar to the sequentiai relationshilts found at Comwall (Lapham and Gray, in preparation). SELECTED REFERENCES llromery, R. lV. aurl otltcrs (1961), Acronrognetic llap ol Part ol the Palnl,ra Quacl- t'angle, Daupltirr and Lebarton Coutttit,s, Pertnsyh,ania, L!. S. Ccological Survcy', Gcophysical Invcstigatiorrs IIap (;P-2{i8. Carswell, L. l). and others (1968), Gt'o[og1'utttl htdrologt ol the f,lartinsburg Shale in Daupltin County, Pennsyluattia, Ita. Ccol. Surycl , ,lttr scries, llrrll. \V 24. lroose, R. II. (195 l), (]rourtrl ll'uter Cort.sentulion nnrl l)euelolttnerrt itt I)tutphin Cowtty, Pa. Dcpt. Irrternal r\tfairs trlonthly Bull.. r,. lg. No. l, p. IT 2ft. (1953), ()rounrl -u,aler behtn,ior'itt thc IIersltt,t, l'allet,, I'euns\lutrtin. (jcol. Soc. r\mcrica lltrll., r. 61, r:o. O, p. G23 G{ti. (ltl67), Sirtkltole I:orrnatiort |ty ()rountl -trater ll itltdrazt,al: I;ur ll't.sl IIttttd, Soutlt ..tlrica, Scieuce, \'ol. 157. No. 37f)?, p. l0{5-l0.lS. Geyer', A. R. (1956), Ccology ol tlre t,icirrity ol the Hershey A|iue, Hershey, Pennsyl- uartiQ, Unpuhlished I\I.S. clisscrtation, {i9 p., Univ. of Michigau, Ann Arbor, Mich. attd othr:rs (19118), Gcolog,- ol tlte I-eltanon {)uadrangle, Pa., Pa. Gcol, Srrr- vcy, 4th scrics, tlull. r\167c. Gra,v, Carlylc (l{}ir2). Tht: ltidt calciturt litnt:srone o1 )t,, Annuille belt in I-ebanon antl Berhs Cotnlies, Itetrnsy!7r477ia, Pa. Ccol. Strrvr:1,, -lth serics, Bull. PR 140. Holrsorr, J. P., Jr. (1963), Stnttigmphl' ol the Ileekntnntotttn Croutt irt sotttheastern Pertnsyhtattia, Pa. (it:ol. Sur.r'er, .lth scrics, Ilull. G 57. i\faclaclrlan, l). B. (1967), Strru'tttre anrl .\lratigraltltt, ol the l-irtte.stonrs antl Dopt- rttites of l)auphin Cowttt', Penn.ty,lvlpia, l,a. Geol. Survcv, 4th scrics, Ilrrll. G .14. trfcisler, Harold (1963),f11rlr'ogeoloey ol the carbonate rocks ol tlte Lebanort l/a!!ey, Pennsylvt64in, l,a. (;eol. Surr.cy, .ltlr scries, Brrll. \t/ lg. N{osclcy, Jolru It. (19i2), I-itttevlartcs zt'ithin tlte belt ol thc ,l!ortinsbtu-{ Crottlt i4 I"ebattatt (iourttl', Pt:rtrt.s1'htania, l);r. r\catl, S<.i. proc., r.26, p. 7g_gir. (1954), Cro.ss lattlts irt tltc 'Ilortinsburg l;otrnaliott, I-ebonon Cottnry, pt:rtrt- sylvania, I,a. ,,\cad. Sci. Proc., v. 18, p. ISJ-l 12. 46 PALMYRA qUADRANGLE shales and o,Ncill, B. J. an ta ? tt lF? \) ENYTRONNIENTAL CEOIOGIC FACIOTS :e$(cd +(wr{Ec.N.1r'tt t! ni: \: *i" { :l :t ...i t I rl ,! ""j,' t .\ { .l- ;:. : \ ]l :l : 1 i.i.i ,l il _, .i\ ,c ti itt il ! ri il .1, f 'l s t j I 5 f, J\ fr il J I il ill (Jt ;i\ (i l,t()1.( )r ;l(' ll.\ l' ()l.-l'l l l,l l'.\ l.i\tYli'\ l)lir\N( illll Itljrr ( il:( )l.rr( il(' ( li()ss $l'l(' I l{ }i's - -t ,:.\\$r -\- ,_ rul .,i:!rri. .\ l.l ,,i' la .t jrj :k' ) g MP TEGTNO -J. 1: .1i",'r1;;r:;L1',. :- '. I .t' :: :1; ::'.:i;',;r' :.1,1 .rr Irtr r i.i,itr)Ntitr\r:. t: 1 ,lrrit,Ltj l_trlr i,.rit: i I o ,r-i:r r !i:i irrir\l\n o fi ? o :: _.1'I'. ' i' !? J o rr f, r:rri! | i.ir:! \rir,r !l F. ..i'].:':',..'','^.'. a t ;r{j\rrir lln. I rlr\r \rt.r\ ).... z s c : ::Sl f I I {:r-*Er;l" " ig'-'*"*' , 1 ..:,1' ,/.'r, i-;ili.- L:t . , ii,:ii , -^' z ; l- zal \!: li si 0i) J ....'. : "-'1 '--' ' t-ft";1, 6&', l.-111\ ,;- ._j .k -. ! r.! E--1.-' "' 5fi t-j.*i,-., la.*' =*'*" sY[190r.s (ll:l0l O(liC lL\l OF 1'lll:l l,r\t,]lYltr\ QUADltr\NGLll I 1!i0 ,,,,i,;,.i:; ., - -, -i-- ' ,,'--:'' clir )i_o(l(, (.t()ss slicl tor..s .{_ , -....{' .E-f:ffSj t, i:- A' \ ii: \s\\ =i:'-ryNffiL .\- 'l:. .'.\\ ' 'L\ a limestone quarry located north of Palmyra.