PQSS!8%LITY OF DETERJWRENG RESTRiCTED REEF CDNGWONS FROM THE AREAL DiSTRBUTION OF THE WIE‘EL‘! DISTRIBUTED CQNTEMPORANEOUS DETRITAL AND LA‘GUNAL FAs‘ZiES The-sis {‘or the Deane 9f M... 5. MICHIGAN 31'ATE COLLiGE Comeiius Siman Verhoeven 1948 THESIS M-795 This is to certify that the thesis entitled "Possibilities of Determining Re- stricted Reef Conditions from the Areal Distribution of widely Distributed Con- temporaneous Detrital and Lagunal Fecies" presented by Cornelius S. Verhoeven has been accepted towards fulfillment of the requirements for __M_' S°____degree in Geology N. a. A/ __-___ Major profess 1' Date September 10, 12.3 ._4LAAI> _-_;_;_r_i_:!__A_‘L-___‘.‘Zl__in_‘ri LA _ OVERDUE FINES: 25¢ per day per item RETURNING LIBRARY MATERIALS: Place in book return to remove charge from circulation records POSSIBILITY OF DETEIWINING RESTRICTED REEF CONDITIONS FROM ‘EE LREAL DISTRIBUTION OF THE WIDELY DISTRIBUTED CONTEMPOBLNEOUS DEI‘RITAL AND IAGUNLL FACIB By Cornelius Simon Yerhceven A -18 Submitted to the School of Grednete Studies of nchigen State College of Agriculture and Applied Science in pertiel fulfillment of the requiraeente for the degree of “STE 01' SCIENCE Department of Geology and Geography 1948 THESIS Um? CONTENTS Introduction Nature or the Problan Location or Boundaries of the.Lrea Procedure Acknowledgements Tapography and Relief Drainage Stratigraphy Bell Shale nockport Quarry Limestone Ferron Point Fermation Genahaw,rormation Newton Creek Formation Koehler Formation Gravel Point Formation Outcrop Localitiee Iaciee Deve10pment Reef Building Organieme Poseibility of a Barrier Reef in the Onaway~ Ocqueoc Area Structure Conclusions Page no r- r- ya (39‘6“ 11 12 13 14 87 89 1. ‘e 5. 6. 7. Index lap composite Section or the Genshas romation in the Onavay-Ooqueoc Region. lisp Shosing Relationship Between Rainy River Channel and Genshas Outerope in Sections 88 and 3'7, North Allis Tonship. Correlation of Geologic Sections in Onasay- Ooqueec Area. lap Showing Outcrop Localities in the Black Lake Area. Aerial Distribution of the Traverse Group in the Ona'ay-Ocqueoc Region. Structural Contour Map on the Top or the Rockport Quarry Limestone. 10 10 1‘ INTRODUCTIOH mm 01' EE PROBLEM This thesis is a report of field studies and laboratory examination of the fomations of the Traverse Group of the middle Devonian in western Presque Isle county, llichigan. The purpose of the study was to determine the areal distribution of the various formations and to map and attempt an explanation of the structures present. The identification of the Traverse formations was made al- most entirely on lithologio characteristics. Faunal zones were used for detemining the approximate positions of the outcrops in the stratigraphic column. Fossils are especially important in the Genshaw formation where the lithology is similar throughout the entire section. The thin Ferron Point masher is recognized by both lithology and fauna. It is not within the scope of this paper to describe and classify these fossils. but some species described by G. W. Smith in the Afton-Guam area and recognized in the region covered by this report are mentioned. LOCATION OF BOUNDARIE OF THE AREA. The area described is located in Presque Isle county in the lower Peninsula of Michigan, and occupies approximately 50 square niles. A line drawn between the abandoned Onavsy Stone Company quarry on the south shore of Black Lake to the Disappearing River is the northern boundary of the area. The southern boundary is the Detroit and lackinac GOGENC WI}..\ “~-—. 0‘ °~8}‘\ N MICHIGAN GEOLOGICAL s 4 4 x: s u P E R I 0 R \ DOMINION OF CANADA I BANAGA ~J 3" Q ‘~ amount: ' w“ ALGER ”m" V scuOOLann "'an . ”Okr Noucxmsou mm“ ‘ \3 ” CH4NN£L O I .° 0 . 0f . 0 A 0 - y,”- “fl/ ti" VI” ‘- A A [6' / if 3 cmmvoux - i (“/1903 m,“ orszco lemmas! ALPENA§ to . t x ’t mam F s / a 9 : V stuzlc came KALKASKA camrono OSCODA ALCONA I TIAVERSC . 3'- l' \ Q . .1. Ism: wrxrono mssAuncTcscom comm IOSCO :0 .'/ 9 o I ARENAC . \ MASON LAKE oscmu cunt cuowm e Z / I by HURON .' m 5» I 'OCEANA accosn ISABELLA mOLAuo ; ntsAvco LA \ tusco SANILAC “3‘ acumua GRAIIOT “m“ . ’l k\ mu curse: mm SAINT . '. 0mm IONA cuntou £ CW" V I _J—7 ‘4 ' A MACOIB I OAKLAND . ALLEGAI um wow wow LNNGSTON I M . . srcwv I m BUR" MLAaAz CALHOUN JACKSON WASHTENAV WAYNE i i CANADA -' mm 5‘- / “55 3W6" iLLSOALt Limit: MONROE . JOSEPH ...... '-.. .-..-. -..-b.-.. .C_.. IND ANA 'r'—" OuHIO DEPARTMENT OF CONS RVATION VISION SURVEY “I...“ C? I Railroad between the towns of Onaway and Millersburg. The area is bounded on the west by highway 15-211 and on the east by highway Its-23. Location 15 is outside these boundaries, being three and one-half miles east and two miles south of Onawav. PROCEDURE Several trips into this area preliminary to the field work Iere made by the writer. An introduction to the Traverse Group was given by Dr. W. A. Kelly during a field stratigraphy course offered by the department of Geology at Michigan State College. Outcrops of the Traverse Group in other areas were also visited. The field work was completed in seven weeks during the suner of 1948. Stream valleys were traversed on foot and the roads were travel- ed by auto. The field mapping was done largely on sketches made from aerial photos. A base map was constructed from aerial photos with a scale of one inch equals 8,000 feet. The radial line, steel t-plate method see mployed in preparing the map with horizontal control points being taken from the original survey of the area. Elevations were obtained by the three base altimeter method with the high and low base elevations being carried from known elevations established by 1’. G. Devell. Within a mall area a single altimeter was used and rechecked at established points. OutcrOps along the rivers were mapped in by spotting on the aerial photos. Speedometer readings were used in establishing locations along the highways of the area. ACKNOWLEDGEMENTS The writer expresses thanks to Dr. I. A. Kelly for his field and laboratory assistance, the aid in preparation of the base map and the wealth of information given on the subject. Dr. S. G. Bergquist's assistance in the preparation of the thesis, and arrange- ment of aid in the laboratory is deeply appreciated. To Dr. B. T. Sandefur, the writer expresses appreciation for laboratory assistance. The field work was accomplished with financial aid from the lichigan Geological Survey. TOPOGRAPHY AND RELIH Glacial features appear to dominate the tepography cf the Onaway-0equeoc region. The glacial drift is relatively thin but ef- fectively covers most of the area. Relief is low, not exceeding 250 feet, although the glacial features are sufficiently sharp and well defined to be recognised easily. Drumlins are common in the area and new be observed on the aerial photos. One large belt of drumlins occurs Just cast of Onaway and a second group is found west of the Ocquecc River. The relief in the area is due in part to rock forma- tions where erosion has exposed bedrock to form escarpments. The rerron Point formation offers little resistance to erosion and is easily undermined, often leaving the overlying Gcnshaw Tor-nation as a well defined bluff. DRAINAGE TIO major rivers cross the area. The Rainy River, the most westerly of the drainage ways, has its headwaters in southwestern Presque Isle county and flows northwest to Black Lake. The Ocqueoc River which parallels the Rainy, flows north from May Lake in south- ern Presque Isle county to Lake Huron. During the dry season these streams are chalice and have little velocity but in periods Of heavy rainfall they have a sufficient volume to cut appreciably into bed rock. Rapids are common and each of the rivers has a small water fall which ex- poses a relatively thick section. Black Lake, the only lake in the area, is probably bottomed on the Bell shale. In the areas to the north and west where outcrops are lacking, sand plains seem to dominate the surface expression. STRATIGRAPHY The entire section of the Michigan Traverse Group of rocks is not found in this area. A. S. Warthin, Jr. and G. A. GOOper describe the Tour Mile Dam, Norway Point, Thunder Bay and Squaw Bey- members of the Traverse Group in the Thunder Bay region of eastern Michigan. These are not found in the Onaway-Ocqueoc region. The Traverse Group of the Onawey-Ocqueoc region includes the Bell shale, the Rockport Quarry lime- stone, the Terron.Point shale, the Genshaw formation, the Koehler formation and the Gravel Point formation. The formations of the Traverse Group are here described in the order of ascending age. BELL SHALE.-The Bell shale does not outcrop in this region, although it is probable that the floor of Black Lake is on this member. The Bell shale outcrops northwest of Black Lake on the banks of the Milligan River. The shale is reported as being present in two different wells that were drilled in this region. In the Lobdell-Emory manufactur- ingCompany well, which has an elevation of 775.0' above sea level, and located in the SE. is, es. in Sec. 26, r. as N., R. 2 3., in Allis town- ship, the Bell shale was encountered 138 feet below the surface. In the Presque Isle Development Company well, with an elevation of 839.0' above sea level, located in the as. i, NW. 73:, Sec. 5, r. 34 N., R 2 E., near the City of Onaway, the shale is recorded 250 feet below the surface. ROCKFORT QUARRY LIMESTONE.-The type locality of this formation is the quarry at Rockport, Alpena county (Warthin and Cooper, 1943, P. 580). In the Onaway-Ocqueoc region, the Rockport Quarry formation is represented by two distinct facies, both of which are present in the abandoned quarry at Black Lake. The upper, and more extensive facies is a light gray, dense, even-bedded, stylolitic, sub-lithographic limestone with abundant secondary calcite fillings. Several flat-lying Pavositee zones, together with thin shale partings, interrupt the otherwise continuous sub-lithographic texture of the limestone. The dark argillaceous facies which also has flat-lying Favosites zones is represented by the lower five feet of section at Black Lake. ,A cup coral zone is found in the dark facies at the Disappearing River (loo. 52) and at the Ocqueoc Falls (loo. 31). The dark gray argillaceous limestone is of detrital origin and shows a characteris- tic wavy structure caused by dark streaks of organic matter. The greater part of the material is in the form of crinoid columns and shell fragments set in an argillaceous matrix. None of the dense sub- lithographic section is shown at the two latter locations. The facies change will be discussed later in this report. 'SECTION AT OCQUEOC FALLS Rockport Quarry limestone _ Poet Inches 10. Limestone; shaly, black, detrital. 8 9. Limestone; massive, dark, detrital, wavy structure. 4 6 e. Limestone; shaly, black, Favosites bed. a 7. Limestone; massive, brown detrital, Hexagonaria and Favosites. 2 6. Limestone; shaly, black, Favosites bed. 1 S 5. Shale; black, thin-bedded, non-fossiliferous. 2 4. Limestone; brown, detrital, wavy structure. 2 2 3. Limestone; massive, brown, crystalline. l 6 2. Limestone; shaly, black, Favosites bed. 6 6 l. Limestone; dark, detrital. 3 6 MON AT ONAWAY LIMESTONE COIH’ANY QUARRY Genshaw rest Inches 8. Limestone; massive, many Hflnaria. lO Icrron Point formation 7e 01", .hdge Rockport Quarry Limestone 6. Limestone; gray, sub-lithographic, calcite fillings, stylolite zones. 16 5. Limestone; grey, sub-lithographic, large calcite fillings. l 4. Limestone; shaly, black, Favosites bed. 1 3. Limestone; gray, sub-lithographic, stylolitic, calcite fillings. 19 7 S. Limestone; shaly, black, Favosites bed. 4 l. Limestone; detrital facies. IERRON POINT FORMATION.--The type locality of the rerron Point formation is the same as that Of the Rockport Quarry limestone. Outcrops of this formation are relatively scarce in the Onaway-Ocqueoc region. At no location is the entire section exposed, but the estimated thickness of the Ferron Point formation in this area is 10 feet. The Terran Point usually is represented by a concealed interval with fossil evidence in the weathered zone to support its presence. At the Black Lake Quarry the lower foot of the rerron Point formation, exposed by digging into the slump above the top of the Rockport Quarry limestone, is composed of grey, soft, fossiliferous clay shale. Terron Point fossils are numerous in the slump both above and below the contact of the Terron Point and Rockport Quarry formations at Black Lake. ,At location 46, the Rainy River cuts through the Genshaw and Ferron Point formations but a por— tion of the Barron Point is represented as a concealed interval. It is underlain at this location by the sub-lithographic facies of the Rockport Quarry limestone. Both the Rockport Quarry limestone and the lower Genshaw beds are exposed at locations 9 and 10 on the Rainy River. The vertical interval between these two formations is ten feet, which represents the apparentthickness of the Ferron Point formation in this region. This interval of ten feet is considerably less than the 37 feet of beds ascribed to the Ferron Point fermation in the Thunder Bay region. It is possible that one or more of the lower fossiliferous shale zones that are placed by the writer in the lower Genshaw may have been included in the Ferron Point formation in the Thun- der Bay region, described by Warthin and COOper. A.composite section of the Ferron Point formation in the Onaway-Ocqueoc region is as follows: Genshaw Feet Inches 8. Limestone; dark gray, Hexagonaria. Ferron Point 7. Limestone; shaly, blue. ' ? 6. Concealed 5. Limestone;:massive, gray. 2 4. Shale; blue, Chonetes Fragilis. 2 3. Limestone; shaly, blue, blocky, no fossils. l 2. Concealed interval. Rockport Quarry limestone l. Limestone; light gray, sub-lithographic. COMPOSITE SECTION 01' m GENSHAW FORMATION IN THE ONAWAY-OCQUEOO AREA. E Limestone E Shaly Limestone Shale D Concealed i 8- H i 1 s u I". " I i es-Cyrtina Zone 1 i 8 ‘ i T a . a e3 . i a ' O .5“ 8 ' v4 2 9 ‘ *3 ~ 3 3 - Coral Zone Shale No. l ' Zone 0 4' fer-q :Pgiht ; _, , Bed 5 is highly fossiliferous and carries numerous remains of £53223, Brachyspirifer,'ggggggparia, uncrospirifer, Trilobite, Czrtina, Bazozoan, Crinoid columns, Cup Corals and Favositcs. Bed 4 is a zone composed of Chonetes Fragilis together with a large species of Brachyspirifer. The Ferron Point type of.Hgggggnaria is one comp men to shale zones, with complete specimens ranging from.two to eight inches in diameter. GINSEAW FORvIATION.-The Genshaw formation originally had its type locality in the NE. A, r. 32 N., a. s 3., Alpena County. The amended section of Farthin and 000por is a.composite one with type localities at the Alpena Portland Cement Company shale quarry, on the Long Lake Road, along French Road, and in the Michigan Alkali Company quarry, respectively. Including 35 feet of beds above the Killians masher, the entire section of the Genshaw formation measures 116 feet in the Thunder Bay region. In the Afton-Onawey area (I. A. Kelly and G. W. Smith) the Genshaw has a thickness of 150 feet with no beds higher than the Killians member. In the area included in this report, the Killians formation is probably overlain by a thin bed of upper Genshaw age. Locality 19 is the only outcrOp in this area that could be as- cribed to the Genshaw above the Killians member. Shale members rich in fauna are common in the Genshaw. Because of the similarity of lithology below the Killians manber, these shale members were used in ascribing the scattered outcrOps to their correct position in the stratigraphic column. It is doubtful that all of the --- I--- l #hm.23 I I . # \ \ aloe. 24 \ \ \ I! i \ \ ’ .‘ \\ .\" // fl \ I / I ,/ i I,/ ‘filoc. 42 'I” /’-‘\ l -l ’I” ‘\ // \\# I ‘s-” \\ I \\ I \ I Ross School Road a .l. —— —.__‘__-..———- Scale: ‘5 inghes : 1 mile 'NAP’SHOWING RELETIONSHIP BETWEEN RAINY RIVER CHANNEL AND GENSHAN'OUTCROPS IN SECTIONS 88 AND 27, NORTH,ALLIS TOWNSHIP Plate 3 -10- shale members in the Genshaw formation were located, however, by use of well logs and outcrops, a composite section was constructed. (Plate 2) . The lower 56 feet of the section is found at the Rainy River Falls (loo. 13). Number 3 shale zone at the level of the falls contain- ing species of Brachyspirifer, small StrOpheodonta, Favosites, m, PholidostroPhia, and Mucrospirifer, is the highest of three shaly, foes- iliferous beds exposed at this location. Shale manber number 2 is a blue clay which is exposed only when the water level below the falls is low. The fauna of this member is composed largely of mall Mucroepirifer and C ina. Shale member number 1 has large numbers of the smooth umbo type of Pemtemcrella, m, Cg Corals, Favosites, Mucrospirifer, Schiao horia,' Strephecdonta, c tina, and Chonetes. The lower 10 feet of the Genaiaw formation is characterized by the presence of an abundance of Hc_x_§_gonaria. Shale beds 2., 3, and 4 are all contained in a 50 foot section referred to as the Clathrodictyon zone. The zone ranges from 25 to 75 feet above the base of the Genshaw formation but the fossil from which the zone is named does not occur in abundance below the massive limestone bed between shale layers 2 and 3. The Clathrodietyon is a stromotOporoid which grows in concentric lwers around some other fossil. The centers of the Clathrodictyon are usually m, Pentamerella or Brachyspirifer, although several with GastrOpods as cores were found. The upper Clathrodictzon zone is characterized by a prevalence of acetate umbo Pentamerella and Brachyspirifcr while the lower portion contains abundant specimens of a anooth umbo Pentamereljlé in association with Bracgzspirifer. Shale umber d is characterized by the presence of many specimens of m. Chonetes, associated with C ina, are abundant in shale zone 8 which is 12 feet above the hp of the Clathrcdictyon zone. This zone, with a thickness of about six feet, is exposed on a hillside at loo. 42 (Plate 3). The Genshaw above the Chonetes zone is concealed below the Killians, which has a thickness of approximately 80 feet in this region. OutcrOps are few. due to the ease in which this member is weathered. The Killians member is a black, detrital, shaly limestone with the most comon fossils being Macrospirifer, Gcghoceras, pygidia of the trilobite Proetus, and a coral, Favosites. The Favosites often show dark bituminous penetraticns into the corallites. Except for the intercol- ated shale layers, the lithology of the Genshaw formation is similar throughout the entire section, being composed of detrital limestone ranging from light gray to dark gray in color. Black detrital beds occur both above and below the shale layer number 1. NEWTON CREFK LIMISTONE.-The type locality of the Newton Creek limestone is in the quarry of the Michigan Alkali Company at Alpena, Michigan (Warthin and Cooper). This formation is described as a dark brown, crystalline limestone having an approximate thickness of 25 feet in the Thunder Bay region. Large fragments of limestone, considered by the writer as possibly belonging to the Newton Creek formation, are found associated with the Killians manber of the Genshaw formation in this area. These fragments occur in large numbers in a field to the north of the‘Vilburn School (10c. 35). Similar fragments are also found in the bed of the Ooqueoo River (loc. 2) at the Junction of highway'Mézll and the Rowe School Road (loo. 19), and also at location 20 on the Rowe School Road. The thickness of the Newton Creek formation in this area is not known but it.must be considerably less than 35 feet as determined at Alpena. KOEHLEB FORMATION.-In the Onslay Stone Company quarry south of the airport at Onaway, several beds are exposed which do not fit into the . described section of the Traverse Group. These beds lie above the'Newton Creek lhmestone and below the Gravel Point formation, and thus must be Kbehler in age. This series of beds, with approximately four feet of vertical section exposed, is being quarried for building stone. The following section shows the beds exposed at the Onslay Stone Company quarry: Overlying formation not exposed. Feet Inches 5. Limestone; dark gray, coarsely crystalline, detrital. . 8 4. Limestone; shaly to sandy, light gray, even- bedded. 3. Limestone; massive, dense, dark gray. l 8 8e StYIOlite Zone. 1 l. Limestone; gray, dense, thin-bedded. l 6 The type locality of the Koehler fOrmation in the Afton- Onavay area is the abandoned quarry of the Campbell Stone Company 106- ated one mdle north of Afton in.Koehler township (I..a. Kelly and G. -13- N. Smith). The Koehler is composed chiefly of gray, thin bedded, dense limestone of sub-lithographic textures. Except for fragments, fossils in the detrital beds are absent in the Onaway member. It is probable that the four feet of section at the Onaway Stone Company quarry does not represent the entire thickness of the Koehler formation in this region. The Presque Isle Development Company well (log by R. A. Smith) located merely 50 feet north of the quarry, records 15 feet of gray limestone ascribed by the writer to the Koehler formation. GRAVEL POINT FORMATION .--The Gravel Point is the youngest formation of the Traverse Group exposed in the Onaway-Ocqueoc region. OutcrOps of the Gravel Point limestone are relatively few with the best exposures found on the Ocqueoc River, between Millersburg and the bridge over highway M-GS (loo. 1). Because of concealed intervals, the thickness of this section cannot be accurately determined. The beds exposed at location 1 are shown in the following section: 6. Limestone; crystalline, dark grey. 5. Limestone; coarsely crystalline, light gray to buff. 4. Limestone; finely crystalline, dark gray, massive detrital with conchoidal fracture. 3. Limestone; shaly black. 2.. Limestone; dense, dark, detrital, very fossiliferous, contains m and merospirifigg. 1. Limestone; sandy, but fossiliferous (probably Newton Creek limestone). °.U.E 0c ..;‘~:! :5 - " 7' 332 -A‘ I l i I I OOFQUE 0C 3| LEGEND * Good 90-30 _=— Med-um lloam —-- FOO! RDOG _ q'w.’ Intermmenc Steeam Underqvoynd Shear “ovoid Inner-'12": “a: van“ 1:. Lom'c' W “vs 0 207 4C I B SthOG-MZCSC r SCALE I 24 000 9" Geo", COMPILED 1948 1'! Mora“ * A A [:eaavsu. PT. . ROGKPORT 0. ” ‘\ \ “r 'r “—‘— A—’** ~--y — “fig F ~ \ \ ‘_ - - ' - ' ‘- - - ‘- - - - — - Q ‘ ~ ‘ f 1 "L \ \ _ "49 ,""' -“-- W ’- \ ' _ - - ’ — ‘_ __ __ _ _ § _‘ ~ \ ‘ N x \ \ r ’ ’- __ ’- " '- ' C. ‘ ~ g ‘ ‘ \ \ I \ \ \ \ z r I ’ 6 - — - \‘ 6 ‘ 6 \ \ \ -‘\y ’ I r / ‘ \ ‘ \ J \ \ "\6 \ /‘ I I f \ ‘ 6 \ \L 18 I ’ ‘ \ \ l \ ,1 \ \ I r \ \ ‘ I -- ,“I x \\ \ \ \ / // ‘ \ \ \ - , ’ ‘ x I i ‘ \ \ ‘9 PI IL) ’ // \ I 1 I \ \ I I // \ \ \ \ I I I 36 1 \\ \ ‘ x / \ ‘ j 5 I \ \ m I / ( \ \ ' I 37 ‘ \ \ i ' / * ‘ \ ; I * t \ II ’ r 7‘, - \ I / ‘ I / L' F , , ‘ \ I ’ / \ \ W x I D A I N ‘1 L9 \ \ ‘_ I \ (I ~. ‘ ., V \ \ ’ g I 1/ D 38 \ \ ‘ _ j} /’ bk 9’ v E H. , \ \ \z a ’ g \ \ 2 , ’ ‘ ~ L . , ’ \ \ ' 1 " I 3L3 ’ '4 \ \ f I I ‘ ' ‘1'2 A. . \ \ \ unearfi ’ ‘ ' \ \ // \ N ‘ Jl ‘ \ M : (JOWNI, ogQUEOC ‘ \ t . Aze I -30 ‘ x ‘ \ ) 45 ‘ xx 'x L .. 1 f7 1’ ‘ \ I 32 \ I 8"“ \ * \ ‘ A" \ \ 24 ‘ \ ) .\ ‘9, I ‘ 1/; - - ‘ \~ \ . 4 {\‘p e- ‘ ." ‘ \ ‘ I, K \ "S ' W") ‘\ ‘ l I \~» L is”; ‘r ‘ ‘1 \‘ \\ 45 ' ”‘ “- 1 Q 35 , \2, s; x \ . IOCOUEOC 3| I A , .’\ m \ ? fi—O‘ a \ 6 ’5“ ‘1'" .> ‘ ‘ ' l FALLS 1’ A34 \, A '1‘ ' - r V“. TY?" "\ 1 I , l o \ 22 fly: V I I“=}i'-“=v}"""" ‘ ’ {45. ~ / \ a l a "J , .’ 1": 15417 ‘4 \ 2 [7 x i x' \ x ‘ a‘ 3&8 Ij’ rl/ a, \ .4; 1“" I /W 1,:rv.‘ \ '\\§‘\ I l \L‘ /” \ \ ‘ i! \ '1‘. 1 536‘ 1* \ ‘ ‘ \ i \ 6‘ / I I \ ‘ ‘I‘ ‘ ’ ‘ - ............. A'8 \+ I T \ \ " - - - " 15.2.5 ; J 1 a —- " " '9 ROWE ' ‘ \~-\-' ‘* ‘ \\ ~~ J" I L .— ’ k A SCHE - ,’ ,1 ' \~. a 47: . , ' ' ‘ ~ I , ' \ \\ “’7 \ 2 q I ‘4 \LLQI“ / _ __ _ ~ I , " a- o- ’ ’ ’ § \ ‘ \‘ ‘ x I ’ \ % ‘ DEEP WELLKW / ’ ’ ' \ ‘ A \ \ * l / I , a 13‘". ‘ X \' I ' '32):— >x’ , ’ ' ‘> ~ ~ ‘ _, j + I / RAINY A ‘I , , VILBURNEE \ ‘ ‘ i I { R'VER I I / . SCH \ ‘ e . ' , FALLS , ’ , , ‘\ - c- ‘ I / ’ ’ .— —- fll' —- s ‘ ’ , " s ’ r / , —- " \ ‘ s ~ ’ . ' ‘ x I I ’ ’ r ’ ' N —. _ - - - ‘ I [I r / , ’ ‘ _ \ I I I , ’ I \ I N \ ‘ / , , ’ i \ l I I r ) ' I / I | a E - ~~, .‘, \ ’ \_ [I / / I ‘ . DEEP ‘ > - ’ ’ ' l WELL\ \ ' I, I I I ‘ I .. -_. \ ‘ j I 3L .— v a- / I ' > b\ ‘ I l I \ \ \ ' \ I / , I | gr \ \ ‘ . I l I ‘ g ' r \ \ l /‘ / / ’ I . —/.‘ ‘ I I e ’ : I ‘ I ‘ / / , ‘1‘ ‘ . ' , 1 \ \ \ I I I K ' I , ’ '7 ~1- \ \ ‘ ‘ I ‘ ‘J ' \ (Cg‘fi .-._L A; \\ ' ‘ \ ‘\ / i ‘ I \ . ~~ Lg ‘ ' ‘ ‘ ‘ , ~ . l ‘ I I I I *_L_“ I V \ \\ ‘ ' t \\ M 6 8 \ ONAWAY \0 ~\ « r c - ' _ C ' I ‘ I l I ’ I LEGEND . - z . ’ I " -— Good Rood ' . % Medsum Rood N ‘\ I ‘--_ p00! Rood ) e ‘ l M Q’Ve' if.” ""\.~-~ Inlermmeny S'reom ‘ ‘3 ’— '-~ '.”“-"‘ UfidE'q'olmd Sheen. M 90 "030 . ' 6 x \ y‘a/f . . , ’k‘ / *-+~.-Ab’)hdonea Qaurouv ‘i \ 1 A LOFO’. n P ‘ #6 ‘ ‘ - 0 MI; 0 20’: «so - l “I ' PIER—1‘ “ Schooihccse A'5\ y. . SCALE I124 000 I , duo", I w M ,. COMPILED I948 I 7 , _ ~ on. . M2 3 Li \ _ V. " AREAL D|9TRIPUTION OF THF. TRAVERSE GROUP IN THE ONAWAY - OCAUEOC AREA ~ _ROGKPORT o. -FERRON PT. -GENSHAW -KILLIANS -KoEHLER |:|GR_AVEL PT. ' .r ' , 7 _ V , ,. PLATE 6 - 14 .. 'The Gravel Point formation 13 readily recognized by its lithology, being composed of light to dark gray, dense, thin-bedded limestone. It breaks with a conchoidal fracture and has a metallic ring when struck a blow with a hammer. Fremont-.3 of the Gravel Point are usually found to be sharp, angular and relatively thin. Fossils common to the Gravel Point in this area include relatively fine costate Stropheodonta, small Atma, Bryozoa and Mucrospirifsr. OUTCROP LOCALITIES The outcrOp localities spotted on the areal distribution1map of the area included in this report with elevations above sea level wherever available are as follows: Locality 1. Elevation of the highest exposure is 771.1'. The Gravel Point formation outcrops in the bed and in the banks of the Ocqueoc River (Sec. 7 of Case township). This is a discontinuous out- crop extending from.approximately é mile north of Millersburg on the river to a point 1/8 mile south of highway M-GB bridge. Locality 2. Elevation - 739.0'. Rock approximately in place in the bed of the Ocqusoc River, 1/8 mile south of the bridge on highway uses, N. £3 Sec. 9, Case township. Here the outcrop material is a mixture of fragments derived from the Killians, Newton Creek and K001111015 Locality 3. Elevation - 741.0'. The Killians member of the Genshaw formation is exposed in the field along the east side of the Ooqueoc River, just south of the bridge over highway node, N. i, See. 9, Case township. locality a. The Olathrodictnn zone of the middle Genshaw forma- tion is represented by fragments not in place but sufficiently abundant to be near to the outcrop, 83. k, Sec. 33, Ooqueoc township. Locality 5. Elevation - 698.8'. Lower Genshaw (cup coral zone) is exposed in the bed and in the banks of the Ooqueoc River, 81!. i. Sec. 88, Ooqueoc township. Hexagonaria are abundant and place this locality in the lower 10 to 15 feet of the Genshaw. A small falls is famed on this outcrop. Locality 6. Elevation - 698.8'. The Ierron Point-Genshaw con- tact is exposed in the bed and along the banks of the Ooqueoc River, 83. &, Sec. 28, Ooqueoc township. Locality 7. Bockport Quarry limestone (sub-lithographic facies) is found as talus in a read out on highway 11-211, 1;} miles south of the Onavay State Park. Locality 8. Rockport Quarry limestone (sub-lithographic facies) is exposed in the bed and along the banks of the Rainy River, SE. %. 8E. if, Sec. 9, North Allis township. Locality 9. The elevation of the Rockport at the river level is 653.5'. while at the tsp of the Rockport it is 666.5'. Bockport Quarry limestone is exposed as a ledge approximately 14 feet high, extending for a distance of nearly 500 feet along the banks and in the bed of the Rainy River, NE. &, NE. &, Sec. 16, North Allis township. - 15 - Locality 10. The elevation of the Ferron Point-Genshaw contact is 676.5'. The lower a feet of the Genshaw is exposed 10 feet above the top of the Bockport Quarry limestone at locality 9. The 10 foot interval of the Ferron Point shows no outcrops but the Ferron Point typeifiggggonaria is found in the river bed below the outcrop, NB. fit 1m. i, Sec. 16, North Allis township. Locality 11. .An extension of locality 10 in the river bed consists of large fragments of Rockport Quarry limestone, center of Sec. 15, North.Lllis township. Locality 12. Lower Genshaw float in quantity sufficient to be nearly in place is present in the bed of the Rainy River, approximately 1,000 feet north of the new bridge over the Rainy River on the road leading from highway M—le east to the Village of Ooqueoc, aw. it, See. 15, North Allis township. Locality 13. The elevation at the crest of the falls is 739ed'e The lower 56 feet of the Genshaw formation is found in a discontinuous outcrop at and below the Rainy River falls, SW.-%, Sec. 26, North.Allis township. This outcrop exposes the lower Clathrodictyon zone and the three lower shale members. Shale member 3 is at the falls level; shale member 8 is at the base of the falls and shale member one is about 2,100 feet north of the falls in the bed and banks of the Rainy River. Locality 14. The elevation at the top of the outcrop is 765.4'. The Clathrodictyon zone of the middle Genshaw is present in an abandoned tributary of the Rainy River, SE. é, Sec. 26, North.Allis township. -17- Shale none 4 is found five feet below the uppermost ledge of this out- crop. The' exposure is 550 feet long and approximately 10 feet high at this locality with the Glathrodictzon zone being about 65 feet above the base of the Genshaw fomation. Locality 15. Elevation - 761.5'. The Gravel Point fomation is exposed in the bulldozed portion of a field, 500 feet south of the Detroit and Mackinac Railroad, along the road between sections 13 and 14 of Allis township. Locality 16. Elevation at the top of the black beds is 759.5'. The lower Genshaw formation, present as a discontinuous outcrop on Stony Creek, exposes about 10 feet of beds including a black, shaly, detrital limestone both above and below a shale zone. SE. it, 8!. A}, Sec. £9, North Allis township. Locality 17. A flat-StromotOporoid zone of the Genshaw formation is exposed on the quarter section read of Sec. 29, approximately f of a mile east of highway 31-211. This bed is probably one of the flat- Stromotoporoid zones found intercalated in the Clathrodictzgn zone. locality 18. The elevation at the top of the outcrOp is'804.5'. in exposure of the Clathrodictyeh zone of the upper Genshaw is found north of the in... School. Locality l9. Elevation - 821.5'. Beds belonging either to the Newton Greek or the Genshaw fonnations above the Killians are expos- ed in the outcrOp in the SE. in SE. %, Sec. 20, North Allis township. Although the limestone in the outcrop possesses crystalline character -13.. similar to that of the Newton Creek limestone, it is dark gray rather than dark brown in color which suggests that it may possibly belong to the Upper Genshaw fomation. The locality is the only one in the Onaway- Ocqueoc region that may be ascribed to the Genshaw formation above the Killians. locality 20. Elevation - 821.5'. Loose fragments of Newton Creek limestone and the Killiane menber of the Genshaw formation, possibly near their source, are found along the Rowe School mad at the old railroad grade crossing about 1% miles east of highway 11-211, SE. f, SE. 1-, Sec. 28, North Allis township. . Locality 21. Elevation - 811.6'. Killians beds are exposed on a hillside along the old railroad grade approximately one mile north of the note School Road, NW. in Sec. as, North Allis township. The Killians here is associated with fragments of a blacky sub-lithographic, petroliferous limestone possibly of Upper Genshaw age. Locality 22. Upper Genshaw beds are exposed in a field about 1,800 feet north of loc. 21 in the NE. 4}, Sec. 28, North illis township. Locality 23. The elevation at the tap of the outcrop is 801.9'. and at the bottom it is 775.0'. Upper Genshaw beds are exposed in a long rock ledge roughly paralleling the Rainy River channel in Sec. 22, North Allis township. Plate 3 shows the relationship of its location to localities 24, 42 and the Rainy River channel. Locality 24. Elevation - 785.8'. The Clathrodictmn zone of the upper Genshaw formation is exposed in the same rock ledge as at location -19- 23. The Olethrodictyon zone outcrops intermittently throughout the entire distance of this ledge. Locality 23. Elevation - 804.0. A fossiliferous shaly member of the upper Genshaw fomation is exposed in the walls and diggings of an old abandoned well, SW. f, See. 28, North Allis township. Locality 26. The elevation at the Ferron Point - Bockport Quarry contact as shown at point B on Plate 6 is 638.8'. The Rockport Quarry limestone together with the overlying Ferron Point formation is expos- ed in the abandoned Onaway Limestone Company quarry on the south shore of Black Lake. The Terron Point fomation in this locality is found only on the east end of the quarry. To the northeast of the quarry, along the shore of Black Lake, the lower Genshaw beds are exposed at the place where both the Rockport Quarry limestone and the lemon Point shale dip into the lake, Sec. '7', North Allis township. Approximately 70 feet of composite section is exposed in this locality. Locality 2'7. A flat-Stromotoporoid zone of the lower eleven feet of the Genshaw formation outcrops on the road leading north from point A designated on Plate 6, to the abandoned Onaway Limestone Company quarry at Black Lake. The outcrop is in Sec. 7, North Allis township. Locality 28. Lower Genshaw beds outcrop on the south side of the road between highway M-2ll end Ooqueoc Village, approximately c/lo of a mile west of the village. This outcrOp is so small that it is difficult to determine its correct position in the Genshaw section, N. %, NE. i, Sec. 20, Ooqueoc township. Locality 29. Elevation - 720.1'. Lower Genshaw, (Cup Coral zone) outcrOps in the bed and banks of the Little Rainy River, five miles north of Cement School. The outcrop is in the lower 20' of section of the Genshaw formation and is exposed for a distance of approximately 600 feet. The same beds are exposed in a field bordering the river on the north in the sv. 1}, Nu. &, Sec. 13, North Allis township. Locality 30. Elevation - 760.0'. Lower Genshaw is exposed in a road cut at the corner of sections 16, 17, 21 and 20 in the Village of Ooqueoc. This outcrOp extends as a ledge for a distance of approximate- ly 500 feet to the east. Locality 31. The elevation of the lowest ledge exposed in the river is 653.7'. Rockport Quarry limestone (dark facies) outorOps at Ooqueoc rails, SE. g, Sec. 22, Ooqueoc township. About 60 feet of sec- tion is exposed in the bed and banks of the river. The outcrop extends for a distance of about 500 feet downstream.from.the bridge on highway 08-23. Locality 32. The elevation on the cup coral zone is 687.3'. Bock- port Quarry limestone (dark facies) comes to the surface at the Disappearing River, Sec. 24, Ooqueoc township. It is difficult to measure the section at this location because of slumping caused by wsathering of the softer shale zones. Approximately 20 feet of section is exposed but it cannot be tied into the Ooqueoc Falls section. One small stylolite zone together with shale members and thin beds of crystal- line limestone are present at this location. Locality 33. Elevation - 811.2'. Killians and Newton Creek frag- ments are found as float at the Vilburn School. The Newton Creek lime- stone is abundant as large blocks in the field Just north of the school, NE. 3;. N]. f, See. 32, and an. 9;, sn. 4.1;, Sec. 29, Ooqueoc township. Locality 34. E1evation.- 716.3'. Rockport Quarry limestone (dark facies) is exposed about 200 feet east of the highway US-23 bridge over the Little Ooqueoc River, SE. é, SW. %, Sec. 23, Ooqueoc township. Locality 35. A.flat-Stremotoporoid zone of lower Gendlaw cutcrops in the road bed 6/10 of a mile east of the corner of sections 20, 21, 28 and 29, North Allis township. Locality 36. Elevation - 709.0'. The lower Genshaw (dark detrital bed) is exposed in an area 7/10 of a mile south of the quarter section road east of the Onaway State Park (Plate 6), on the line be- tween section 16 and 17, North Allis township. Locality 37. Elevation - 739.0'. A.fossiliferous shale bed (No. 2) of lower Genshaw is overlain by a flat-Stromotoporoid zone in the road bed between sections 16 and 17 about 2/10 of a mile south of location 36, North Allis township. Locality 38. Elevation - 745.0’. An exposure.of the Clathrodictyon sons of lower Genshaw, located two-tenths of a mile north of the corner of sections 16, 17, 20 and 21, extends as a ledge for a distance of 200 feet east of the road, North.Allis township. Locality 39. The elevation at the top of the well is 753.0'. An 18 foot section of the Clathrodictyon zone and fossiliferous blue shale -23- (No. 2) is exposed in a dug well, SE. in, SE. i, Sec. 17, North Allis township. The well is bottomed in the blue shale member and a single specimen of Clathrodictyon was found one foot from.the top of the well. This, together with other fossil evidence seems to indicate that the blue shale is the same as that found directly below the Rainy River falls. Locality 40. Elevation - 837.5'. Kbehler formation is exposed in the Onaway Stone Company quarry, approximately 200 feet south of the air- port and 50 feet north of the Presque Isle Deve10pment Company well, NE. %, Sec. 5, Allis township. Locality 41. Elevation - 756,9'. Genshaw beds are exposed in an excavation for a barn, one mile west of Ooqueoc falls, NW. &, NE. i, Sec. 28, Ooqueoc township. Locality 42. Elevation - 767.0'. The Chonetes Pragilis zone is exposed in a continuation of the rock ledge described at locality 23 (Plate 3). Locality 43. Elevation - 765.0'. The Genshaw formation outcrops on highway Mhzll about two and one-half miles north of Onaway and 50 feet north of intersection of sections 19, 20, 29, 30, Nbrth.Allis township. Locality 44. The Rockport Quarry lbmestone (dark facies), with very little section showing, is exposed on the south bank of the Ooqueoc River, SW. 3:, NE. 4}, Sec. 27, Ooqueoc township. Locality 45. The Genshaw formation outcrops on the west side of the road, i- mile south of Godin School, SE. 1%: NE. k, Sec. 19, Ooqueoc township. Locality 46. Elevation - 701.9'. The contact between the Ferron Point and the Genshaw fomations is exposed in the bed of the Rainy River about 3,310 feet below the falls, 1:. it, SW. g. Sec. 26, North Allie township. Locality 47. Elevation - 695.4'. Rockport Quarry limestone (sub-lithographic facies) is exposed in the bed of the Rainy River, 3,985 feetfibelow the falls, 1:. p, sw. é, Sec. 26, North Allie township. Locality 48. The Gravel Point formation (7) is exposed in a cut- bank of the Detroit and thkinac Railroad, one and one-fourth miles west of highway'Mble. This outcrop is very small and shows not more than one foot of section. Locality 49. Elevation - 621.0'. Rockport Quarry limestone (sub-lithographic facies) cr0ps out in the bed and banks of the Rainy River (Plate 6), SW. i, NI. %, Sec. 9, North Allis township where the east-west quarter section road of Sec. 8 intersects the river. Locality 50. Middle Genshaw outcrOps in the road as a rock ledge on the roadside, 50 feet north of the Ooqueoc church, E. 1,5, NE. in Sec. 29, Ooqueoc township. locality 51. Elevation - scoo'. Logged by R. A. Smith from drillers notes and log, and from.samp1es,. the Presquc Isle Development Company well located in the SE. i, M. in Sec. 5, 'r. 34 N.. a s 3.. shows the following section through the traverse Group: -24... PIEISTOCENE: Thickness gth {Feeti Feet Drift: Clay, pink, calcareous. 10 lo DEVONIAN: Traverse: Limestone; gray. 15 35 Limestone; buff to dark gray- in color,‘ argillaceous limestone with strong odor of petroleum. 100 125 Limestone; gray, granular, bituminous, fossiliferous, with crinoids and corals; much white calcite. 15 140 Shale: gray, soft, calcareous. 10 150 Limestone; gray with much disseminated cal- cite; fossiliferous (corals). 30 1'70 Limestone; dark, highly calcareous black shale; dissuainated calcite. 60 850 Bell: Shale; grew, brown and black, slightly cal- careous. 60 Locality 52. Elevation - 787.0'. Record by C. F. Poindezter from drillers log and samples. The Lobdell-Enory Manufacturing Company well located 409 feet west and 280 feet north of the southeast corner of Sec. 26, T. 35 N., R. 2 E., was drilled through a Traverse section as follows: PIEISTOCENE: Thickness De th feet lfect) Drift: 85 25 DEVONIAN: Traverse: Limestone; gray, shaly. 15 40 Limestone; gray, variegated, shaly, fossiliferous. 50 9O Limestone and dolomite; brown and dark brown, variegated. 30 180 Limestone; light brown. 18 138 Bell: Shale; no samples. 49 18'? EACIES DEVELOPMENT The Rockport Quarry limestone in this area is represented by two facies, namely: a lagunal, sub-lithographic type and a dark gray, argillaceous and fossiliferous type. This change of character occurs in a distance of less than 10 sales. Both facies are found at Black Lake (loo. 36) and in.the Presque Isle Development Company uoll (loo. 51) with the sub-lithographic being the higher. In the Rainy River Falls area, it appears that the light facies is the only one represented while farther east, at the Ooqueoc Falls region, only the dark facies is found. It is possible that the light facies referred to above is here represented in a concealed_interval although the short separation of the dark facies cf the falls from the Ferron Point at loc. 6 would suggest that such is not the case. W. A. Kelly and.G. W. Smith report only the dense facies at Shanty Rapids in the Afton-Onaway area. .L sharp uplift of the beds underlying the Rockport Quarry formation, might have caused the facies change by the formation of a barrier ridge which separated the cpen sea from.the land. Such a ridge would have a lagunal type of deposit on the landward side and a detrital type on the seaward side. A.study of the structures present in the Onaway-Ooqueoc region seems to suggest that structure alone was not the cause of the change in deposition. It is more probable that the facies change was the result of the inclination of the beds below the Hockport Quarry fomation together with the subsequent formation of a coral reef. Coral reefs, biostromes and bioherms are common in the Traverse Group and may have been responsible for the abrupt change in deposition. REEF BUILDING ORGANISLE Among the more important reef building organisms may .be list- ed the cup corals, Favosites. StromotOporoids and Egozoa, all of which are ccmon in the Traverse Group. Van Ingen (18) reports that, "the reefs vary from a few inches to 15 feet for the. blanket type and up to 75 feet for certain true coral reefs in the Devonian. The reefs fomed by gydrozoa and Llczonaria (Octocoralla and Favosites) do not appear to have required such pure water as do the true corals. They are found in formations that carry a considerable amount of argillaceous mud, for example, the Favosites--Halysites--_S:tromot0pora reefs of the Rosendale region and elsewhere in the New York Silurian. This scans to be true of some of the gigantic cup corals, as seen in the 75 foot accmnulation of these organisms in the Hamilton Shales of Lord's Hill, Tully Quadrangle, New York." he a rule, corals are found in waters less than 8'7 meters in depth, but some species can survive in waters as deep as 57 to 48 meters. Vaughn (13). Twenhofel (5) states that the upward growth of a coral reef has been determined at 1.5mm per year or ap- proximately 50 cm. in 190 years. Following are some of the theories that have been set forth by geologists and biologists to explain the mode of formation of coral reefs. 1. Darwin (1842) brought forth the subsidence theory in which slow submergence of a shoreline would be gentle enough to allow reefs to grow up rapidly and remain near the surface. 2. Daly's Glacial Control Theory; is a.modificaticn of the sub- sidence theory preposed by Darwin. Daly suggests that the sea level throughout the equatorial area was lowered during glacial times, per- mitting the truncation of continental platforms by wave action. When the water level was again raised conditions were made favorable for the growth of corals. 5. Rain believed that organic deposits could accumulate on still- standing submarine summits. 4. IMhrray proposed a theory similar to that of Rain but explained the accompanying lagoons as resulting from solution. 5. Le Conte, Guppy and Vaughn report that reefs may grow upward from.a shallow bottom.at a considerable distance offshore. 6. Semper and Guppy believe that Pacific Ocean reefs grew upon rising foundations. 7. Agassiz, Guppy, Wharton and Gardiner suggest that reefs grow up from submarine platforms modified by wave action. POSSIBILITY OF A BARRIER REEF IN THE ONAWAY-OCQUEOC AREA The sub-lithographic facies in the area evidently represents lagunal deposition. The light color and the lack of plant and animal remains suggest that land was rather remote from.the reef. The dark facies containing Favosites and cup corals was undoubtedly the source of the reef building organisms. The Bell shale at lcc. 13 is 48 feet higher than at Onaway (loe. 51). The top of the Rockport Quarry limestone dips 15 feet in the same distance and thus shows a thinning of the Rockport Quarry limestone. This dip is due probably to a pre-Rockport structure in which the Bell shale represents the uppermost beds affected by a small uplift. The deposition of the dark facies is believed by the writer to have pinched out against the upraised portions in the beds of the Bell shale between Onaway and loc. 15 on the Rainy River and between Black Lake and Ice. 13. The depth of the sea in the Onaway and Black Lake areas at the time of the Rockport Quarry limestone deposition was shallow enough to allow normal growth of the Favosites. The dark color of these beds would indicate that the shore line was much nearer to the Onaway- Ocqueoc region during this stage than it was during the sub-lithographic facies stage. .A gentle subsidence of the land would place the shore line farther away and also cause the shallow water organisms to grow upward in order to survive. In the growth of the reef, the shoreward deposition would be of the lagunal type while seaward from the reef, the nomal growth of organisms would give rise to the dark facies. ravosites beds in the light colored sub-lithographic facies probably mark a period of subsidence that was too rapid to allow the («x33 36.) 689 37.1 689 .‘49 so: «go SCALE | 24 OOO COMPVLED "348 STRUCTURAL UARRY FORMATION +»— .-:.e.:’...(.‘.. - e ON AWAY —4 LEGEND \ l 3 V0 5 "‘4‘ I Q as ocoueoc 690 FALLS 3' 4.34 T ’4‘ a? K E f 682 \ \ . u ‘ \ \\ / 700 . 5‘) .47b95 J 46 - ‘\ 2:4(565 "5 l\ -- w“ WELL‘ \ 33. 686 I 0.. ' ¥I ‘ r “ ‘ 5 ‘ 667 675% RAINY “LBW“ '. . / RIVER SCH ’ FALLS ' t 'I' ——< 0 #4 \‘ / A. N 1 \\ $ "\ k l v.2: ,‘ ._ MILLER BU G u 20) 4x to ‘ ‘ 1 ~ \ \ [-IKfl» . . ‘ '- t \ /«I \\' SCALE I24 oog \ \ . . ~ I I _ compmaoneoa \ . e. . ‘ I \\_ AV ‘ q s l ‘* J ‘ — “— — -———e‘ r i M STRUCTURAL CONTOUR MAP W Plate 7 ITH ELEVATIONS ON THE TOP OF THE RCCKPORT QUARRY FORMATION -29- reef building organisms to keep pace with the lowering of the see bottom, and was responsible for the dying off of the organisms. This could have occurred if the waters became too deep. A recurrence of reef- forming conditions would require merely a slowing up of subsidence. In summarizing the facies change, it seems probable that a reef formed around a slowly subsiding submarine platform which was structurally high. The slow subsidence is offered as a possible cause of the upward growth of Favosites and cup corals which are common in the dark facies of the Rockport Quarry limestone. The reefs of which at least three are believed to have formed, are separated by episodes of rapid submergence and subsequent drowning. Except for the facies change, no direct evidence exists to support the presence of reefs in the Onaway-Ooqueoc region. However, the area in which the reef would be expected to form has a surface exposure of Genshaw that would be from 10 to 115 feet above any such structure. STRUCTURE Small flexures in the Traverse Group are very common. Good exposures at various quarries show these small structures superimposed upon the regional dip of the formations. For this reason it is hazardous to attempt to calculate the dip on beds which have limited outcrops. Relatively steep dips result locally from these small flexures as shown along the Rainy River about 5,000' below the falls and in the Afton quarry. The regional dip appears to be very gentle in a direction slightly west of south. This slight dip is brought out by the fact that approximately 115' of vertical section is exposed between locations 5 and 7 on the Ooqueoc River. These locations are 12,000' apart. Plate 8 is a structural contour map based on elevations at the top of the Rockport Quarry formation. Elevations at localities where the Genshaw is exposed are subject to an error introduced,by possible misplaCement of that outcrOp in the stratigraphic column. A.composite stratigraphic column is illustrated on Plate 2 which is based on knowb ledge obtained from relatively small and scattered outcrOps. The comp posits section was used in determining the position that the Genshaw outcrops should occupy in the Traverse section. Elevations at local- ities where the Rockport Quarry limestone, the Ferron Point shale, the Koehler formation and the Gravel Point formation were exposed serve to substantiate the elevations given to the localities where the Genshaw outcrops. From.the structural contour*map it is evident that a small symmetrical anticline exists northeast of Onaway. In this report the structure is referred to as the Rainy River Anticline. Field evidence to support folding in this area is found in the Rainy River bed extending from location 9 to location 13. The former of these locations is an outcrop of the Rockport Quarry formation. To the southward along the river, the Rockport outcrOp gives way to Genshaw float of sufficient quantity to suggest proximity to its source. The Genshaw is replaced at loo. 47 by the sub-lithographic facies of the Rockport Quarry formation. At location l5, the Genshaw again outcrops in the river bed. The beds exposed in the scarp between locations 23 and 42 as shown on Plate 5 have a dip to the northeast. The tOp of the Rockport Quarry limestone dr0ps approximately 19 feet between locations 21 and 24, and 38 feet between localities 21 and 12. The nose of the anticline dips into a synclinal trough, (Onaway Syncline) described by W. A. Kelly and G. W. Smith. The beds west of the trough rise into a structural high forming the Black Lake anticline. The Onaway anticline trends generally east and west and has a closure of about 50 feet. The plunge is eastward with a relatively slight dip. The beds appear to resume the normal regional dip along the Ooqueoc River. A saddle east of the Rainy River Falls area is suggested by the strongly dipping beds found near the Lobdell-Emory well (loc. 14). An increase in the angle of dip between the Rainy River Falls and the well, indicated by the elevations on the top of the Rockport Quarry formation, suggests that the relatively strong dip of beds observed at loc. 14 is not local, but may be of fairly widespread deveIOpment. CONCLUSIONS The formations of the Traverse Group of Michigan that are present in the OnawaybOoqueoc region include; the Rockport Quarry lime- stone, the Ferron Point shale, the Genshaw formation, the Newton Creek limestone, the Koehler formation and the Gravel Point formation. The presence of a barrier, whether due to uplift or to the formation of a coral reef is suggested by a facies change within the Rockport Quarry limestone in the Chaney-Ooqueoc region. The two facies are namely; a dark, argillaceous, detrital limestone and a sub-litho- graphic, dense, stylolite limestone. The detrital limestone contains fossils which could withstand wave action and probably represent the seaward side of the barrier while the sub-lithographic facies is a typical lagunal type of deposit. Presence of the dark facies over'most of the area suggests that this stage of deposition occurred previous to a period of subsi- dence. This submergence was slow enough to allow Favosites and cup corals to grow upward rapidly and remain at or near the surface of the water. A small anticline with an east-west trend exists 2.3; miles north of the City.of Onaway. This structure is fringed on the east by a small saddle. BIBLIOGRAPHY SECTION I BOOKS 1e Dana, Jo De . 1875 Corals and Coral Islands. Sampson Low, Low and Searle, London. 348pp 2. Lobsck, A. K. 1939 Geomorpholoq. Mo Grew-Hill Book Company, New York. 413-435 3. Smith, G. W. . 1942 The Ferron Point and Genshga‘; Pomations in Chebozgan and Western Presme Isle CountiesI Michigan. A Thesis. 4. Twenhofel, W. H. 1939 Principles of Sedimentation. Mo Grew-Hill Book Company, New York. 219-328 5. ' 1926 Treatise on Sedimentation. The Williams and Wilkins Company, Baltimore. pp 47, see, 453, 437, 450, sec, 531, 608, 610 SECTION II ammo. PERIODICALS AND SCIENTIFIC JOURNAL ARTICLE 6. D031... '0 H. I 1934 Gardiner on Coral Reefs and Atolls. Journal of Gsolog. 42: 200-217 7. , 1916 Problans Associated With the Study of Coral Reefs. Scientific Monthly, 313-333 8. ° less The Coral Reef Problem. Special Publication of the American Geographical Soci e31, 9 9. Kelly, 7!. A. and Smith, G. W. 1937 Stratigraphy and Structure of the Traverse Group in Afton- Onaway Area, Michigan. Bulletin of the American Association of Petroleum Geologistsl 31: (553—447-469 10 . 12. 15. 14. 15. 16. Lowenstam, H. A. and Dubois, E. P. 1946 Marine Pool, Madison County, a New Type of Oil Reservoir in Illinois. Bulletin of theIIllinois State Geological Survey, 114: 1-30 ‘ Murray, I. 1887 Structure, Origin and Distribution of Coral Reefs and Islands. NatureL 59: 424-428 Van Ingen , Lecture notes. Vfimo 1919 Corals and the Fomation of Coral Reefs. Smithsonian Report for 1917, 240-276 Warthin, A. 8., Jr., and Cooper, G. A. 1943 Traverse Rocks of Thunder Bay Region, Michigan. Bulletin of the American Association of Petroleum Geologists, 27: (ST 571-595 1935 New Iormation Names in the Michigan Devonian. Journal of the Washington Acadauy of Sciences. 25: (12) 525-526 Willard, Bradford 1956 A Hamilton Coral Reef in Pennsylvania. Proceediggs of the Pcngylvania Academy of Science, 10: 50-36 ABSTRACT The Rockport Quarry limestone in the Onaway-Ooqueoc region is represented by two distinct facies, namely: a lagunal, sub-lithographic type, and a dark, argillaceous and fossiliferous type. This change in the character of the formation suggests the possibility of the presence of a barrier reef in the area separating the shore from.the open sea. The extent and exact location of the reef, if present, is not known and at no location does it reach the surface. That the reef does not outcrop is to be expected because the Genshaw formation is exposed in the area where such a barrier could have formed, and thus places the reef below the surface. Subsidence of a small pre-Rockport structure with subsequent formation of a coral reef during the Rockport Quarry stage of deposition is brought forth as a possible explanation for the facies change. The common fossils in the dark facies of the Rockport Quarry limestone are cup corals and Favosites. both of which are reef-building organisms. Several Favosites beds contained within the sub-lithographic facies, are explained as having been formed during an interval of rapid submer- genes in which the reef building organisms were drowned. A slowing up of subsidence would be necessary to resume lagunal conditions. Without more data on the elevations of the formations below the Rockport Quarry formation it is not safe to conclude that a coral reef rather than an uplift is the cause of the facies change. However, a study of conditions for coral reef fomation suggests that a reef may have been formed. The stratigraphy of the Traverse Group in the Onaway-Ooqueoc region is described and compared with the.Afton-Onaway and Thunder Bay regions of Presque Isle County, Michigan. Formations that are present in the area covered by this report are the Rockport Quarry limestone, the Ferron Point shale, the Genshaw formation and the Gravel Point formation. A structural contour map, with elevations based on the top of the Rockport Quarry limestone, indicates the presence of a small anticline, zfi-miles north of Onaway. This structure has an east-west trend and plunges to the east. . I' If“). HICHIGQN STRTE UNIV. LIBRQRIES ll 11 9 312 3102131327