A Geologic _..~ a p of a Portion of the Cornplanter Bridge ?t' Quadrangle , Pennsylvania Presented in Partial Fullfillment of the Requirements for the Bachel or of Science Degree in Geo J ogy & ;< ineralogy at Th e Ohio State University 1983 Robert R. Beckwith Thesis Advisor Department of Geology & ~ inera l ogy i Ai\E 0 NT,E DG :Sr-1EHT S I woul d l ike to thank my a dvisor , Professor Russell O. Ut gard f or his assista n ce , concern , criti cism, editing , and time in the co ~pl etion of this report . I t was gr eatly appr eciated. I would als o like to thank the Wa llace Book and Sta tionery Co mp any of Oil City , Pennsylvania for supplying me with the 7 ~ ' topographic ma p s of the Co r nplanter Bridge Quadrangle . ii TABLE OF CONTE?l\S A ~GIO\'frJ EDGB:· ~ E~TT S •••••••••••••••••••••••••••••••••••••••••••• i TABLE OF FIGURES ••••••••••••••••••••••••••••••••••••••••• iii ABSTRACT••••••••••••••••••••••••••••••••••••••••••••••••••• 1 PURPOSE Af D I NTRODUCTION ••••••••••••••••••••••••••••••••••• 1 T OPO G~A FH Y ••••••••••••••••••••••••••••••••••••••••••••••••• 3 Drainage•••••••••••••••••••••••••••••••••••••••••3 Relief•••••••••••••••••••••••••••••••••••••••••••3 v u ~ - m s Ro cn. ill ••••••••••••••••••••••••••••••••••••••••••••••••• 3 DEVOJ'TI AN & i·-'!I SSI SSI PFI A T SY STE ,1 S ••••••••••••••••••••••••••• 5 Venango Formation••••••••••••••••••••••••••••••••5 Catskill Formation••••••••••••••••••••••••••••••• 5 Shenango- Oswayo Formations ••••••••••••••••••••••• 6 PEl,JN S y1 VA I'·T I Al.\ SY ST E/I ••••••••••••••••••••••••••••••••••••••• 6 Pottsville Group ••••••••••••••••••••••••••••••••• 6 Olean Formation••••••••••••••••••••••••••••••7 Sharon Forn1ation ••••••••••••••••••••••••••••• 7 Connoquenessing Fo r mation •••••••••••••••••••• 7 G ~Oj. O GIC HI STORY 8~ GE01·-10RPHOLOGY •••••••••• •••••• •••••••••••8 Preca~ brian Time•••••••••••••••••••••••••••••••••8 Cambrian Period••••••••••••••••••••••••••••••••••8 Ordovician Period••••••••••••••••••••••••••••••••8 Silurian Period••••••••••••••••••••••••••••••••••8 De vonian Period•••••••••••••••••••••••••••••••••• 9 I- i ssi ssippi an Period ••••••••••••••••••••••••••••• 9 Pennsylvanian Period•••••••••••••••••••••••••••• 10 rr esozoic & Tertiary Times ••••••••••••••••••••••• 10 Pleistocene & Recent Times •••••••••••••••••••••• 10 GEOLOGI C STRUC TURES ••••••••••••••••••••••••••••••••••••••• 11 REFERE(CES•••••••••••••••••••••••••••••••••••••••••••••••• 13 iii TABLE OF FIGURES GEOI .OGI C ~< A P •••••••• • •••••••••••••••••••••••••••• back cover LOCAT ION OF AREA ( fig . 1) ••••••••••••••••••••••••••••••••••2 PHY SI OGR APHI C PROVI 1'J CES 1;AP ( fig . 1 ) •••••••• • •••••••••••••• 2 GEOLOGI C COIJ U\:N (fig. 2) ••••••••••••••••••••••••••••••••••• 4 CR OSS SE CTI OIJ ( fig . 3 ) •••••••••••••••••••••••••••••••••••• 1 2 ABSTR ACT The Cornplanter Bridge 7i' Quadrangle had not previously been ma pped by di rect methods , only indirectly from written reports. Utilizing pace and compass me thods, the Devonian, Eississippian, and Pennsylvanian formations were identified and the corresponding contacts were mapped. This report incl udes a geol ogic map of a portion of the quadrangle, a description of the rock units, topography, and geologic structures, and the geologic history and geomorphology of the region. PUR POSE A1 D INTRODU C TIO~ The purpose of this report is to provide a more reliable geologic map of a portion of the Cornpl anter Bridge 7t' '< _.uadrang1 e , Pennsylvania. Plate 1 is t he area ma pped and is locate d south of t he Allegheny Reservoir and west of Kinzua Creek i n V·'arren and -_er ean Counties, 8 mi l es south of the New York State l~n e (see fig. 1) . Be tween August 10 and 20 , 1982 , this area was ma pped using pace and comp ass methods. Problems we re encountered in mapping because of the heavy vegetati on cover and by close similarities of some of the units. This area i s part of the Allegheny National Forest. Topographically, it is a maturely dissected plateau with numerous ridges and deep valleys. Th e broad ridges are held up by t he r esistant sandstones and congl omerates of the Pottsville Group and are sites of scenic overl ooks . E d ~un d s in 1977 compi 1ed a geol ogic map based on a 1960 state compi l ation sheet and on a report by Lytle and Goth ( 1970) . The r eliabilit y of the contacts we r e noted a s being poor to fair and t he Venango-Catskill facies change was a pproximately l ocated and not based on detailed studies. ,\o'<' c:,eC. N\~c,t. '-°'"'"e ~v..0 Co r nplanter Bridge 7t ' Quadrangle ,e'<'<' ~\.._~Q ~oc, .,_\. \.o 1 ct.~~'- t4:..AH'--~--------- ll'()TTC P . \ ~ · -+ · N PROVINCE Figure I - Physiographic provinces map of Pennsylvania. 3 TOPOGR APHY Drainage The Co r nplanter Bridge Quadrangl e l ies wi t hi n the Allegheny Pl ateau physiographi c province (see fig . 1) . The area is drained by the Al legheny River whi ch flows southwesterly a cross the northwest part of the quadrangle, and by t he Kinzua Creek which f l ows northwe sterly across the area. The Allegheny Reservoir was created wh en t he Kinzua Da rn was con­ structed in the early 1960 1 s across the Allegheny River. Th e dam is l ocated just west of the quadrangle ' s western border. Relief The topography is that of a maturely dissected plateau. The surface is very hilly wi th many short r idges and s purs whi ch have no syst ematic orientation. The r idges are broad a nd comp aratively level on top . The main valleys are deep and narrow and are bounded by steep valls. The highest surface el eva t ion in t he area is 2 151 feet l ocated a pp r oJ~i rn ately on e mi l e south of Dewdrop Campg rounds. The lowest surface el evation is 1328 feet wh i ch is the normal elevation of the reservoir. ROCK UNITS For nations bel on ging to the De vonian , Mississippian , and Pennsylvanian Systems occur a t the surface of the Cornplanter Bridge Quadrangle and total a pproximately 800 feet in thick­ ness . Figur e 2 is a geologi c section near hill 2130 located 1. 25 mi l es west of Camp Cornplanter. 4 AGE FORMAT I ON COL UMN ELEV. DESCRI PTION z < zH < Pottsville > ~ Shale, gray to black, some coal >­en z Fp Conglomerate, well rounded pebbles z t&:l light gray with yellow staining a. Siltstone. 2rav with some coal Sandstone, conglomeratic, dis­ 1950 coidal shaped z Siltstone, dark-gray interbedded < ~~ . -=- . ;_--: H -·-·- With black shale a. a. :.·_.· .,:,·.:. ;." :.· . · . ~ - 1900 H en en Sandstone, coarse-grained, gray H en Shenango f--~i~i;~ 1850 Cf) Shale, dark-gray interbedded with H greenish-gray siltstone ::?!: through Sandstone, fine-grained, greenish­ Oswayo gray Shale, dark-gray MD so Siltstone, greenish-gray r-·-·-·- 1650 Shale, dark greenish-gray Shale, black interbedded with ~reenish-gray siltstone z < Sandstone, fine-grained, gray zH 0 It> ale, dark-red interbedded with > ~ 1500 olack shale 0 Catskill Sandstone, fine-grained, gray 1450 IS hale, red Dck Shale, dark-red interbedded with grav shale 1400 Shale, dark-red interbedded with black shale Venango Shale, black .:·::: ·:.::.:.··.:;:: :·:.;·:. 1350 .·.·· . · i .···::·. - Sandstone, fine-grained, gray Dv Shale, dark-gray-to black F.XPT .AN A'11 J 0 T Conglomerate Siltstone Sandstone Cross-bedded sandstone Shale Figure 2. Ge ologic section near hill 2130. 5 DEV01JI Ai-J Ar D I ·· ~ ISSISSI FP I Ar SYSTEMS In this area , a pproximately 680 feet of Upper Devonian and ~ ississippian rock s are exposed. In ascending order they are the Venango Formation (De vonian), Catskill Formation (Devonian) , and Oswayo through Shenango Formations (Devonian- Mississippian) . Venango Formation This formation has been called the Cattaraugus Formation by Lytl e and other earlier workers. In this area, Socolow has defined the r ocks to be Venango. This formation averages a pproxima tel y 150 feet of exposure. The Allegheny Reservoir is the l ower limit of outcrop with its surface elevation of 1328 feet. The r ock s consist of light gray sil tstones interbedded wi t h bl uish- gray shales and some flaggy gray sandstones. Beds of black sha l e occur throughout . Wher e the Venango interfingcr s wi t h the Catskill Formation , r ed shal es occur. Catskill Formation This formation has been called the Cattaraugus and Oswayo Formations by earlier workers (Lohman, Lytle). So colow defined the rocks as belonging to the Catskill . I t ranges in thickness from 0 to 110 feet, thinning out towards the northwest until it disappears near Dewd rop Run . These rocks include dark red shal e, siltstone, and s andstone with units of gray sandstone in the upper part. The litho­ logies in the upper part display upward fining cycles. 6 Shenango through Oswayo Formations ~ arlier \torkers have called these rocks the Pocono, Kn a pp , or Oswayo Formations. The United States Geologic Survey clas­ sifies these rocks to be Upper Devonian or ~ ississippian in age because no detailed study has been done to divide the ages into specific systems. These rocks include lateral equivalents of the Oswayo Formation , Cusewago Sandstone, Bradford Shale, Corry Sandstone, Cuyahoga Group, and the Shenango Formation . These rocks consists of conglomeratic sandstone and medium­ grained sandstone and several beds of gray to black shales. Greenish- gray , olive, and buff sandstones also occur in vary­ ing a mounts . Be fore the overlying Pennsylvanian rocks were deposited, the area was tilted southward and truncated by erosion. This un­ c onforxity causes a thickness variation from north to south. The thickness ranges froc 500 f eet in the southern part of the quadrangle to 320 feet just south of the reservoir in the northwest section. PENJSYLVANIAN SYST EM The Pottsville Group lies unconformably over the Mississippian strata. The average thickness is approximately 120 feet and the rocks of this group are preserved on the ridges. The Pottsville consists of the Olean, Sharon , and Connoquenessing Formations . 7 Olean Formation The Olean averag es a pproximatel y 50 feet in thi ck ness. It con s i sts of a coars e conglomerate of we ll rounded p ebbles of whi t e quartz ceme n ted i n a sandston e matrix.