Chemical Composition, Stratigraphy, and Depositional Environments of the Black River Group (Middle Ordovician), Southwestern Ohio

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Chemical composition, stratigraphy, and depositional environments of the Black River Group (Middle Ordovician), southwestern Ohio

DAVID A. STITH Ohio Geological Survey, Fountain Square, Building B, Columbus, Ohio 43224

ABSTRACT The Ohio Geological Survey's acquisition porous, very argillaceous tan to light-gray in 1971 of three mineral exploration cores dolomite with some intercalated green The chemical composition and stratig- provided a means of examining the Black shale. raphy of the Black River Group in south- River Group. The study area in southwest- Correlatives of the Trenton are the Tren- western Ohio were studied. Chemical ern Ohio (Fig. 1) (Stith, 1979) is limited to ton Limestone in Indiana and the Lexington analyses were done on two cores of the where the high-purity zones of the Black Limestone in Kentucky. The Black River Black River from Adams and Brown Coun- River generally are less than 2,000 ft deep. Group is correlative to the Black River ties, Ohio. These studies show that sub- The lithology of the Black River Group Limestone in Indiana and the High Bridge stantial reserves of high-carbonate rock was studied in detail in the three cores Group in Kentucky. The High Bridge is (96% to 98 + % CaCO:! plus MgCO,) are (Adams, Brown, and Highland Counties). composed of, in ascending order, the Camp present in the Black River at depths of less In addition, five shorter (10- to 50-ft) cores, Nelson Limestone, the Oregon Formation, than 800 ft, in proximity to Cincinnati and geophysical logs from 50 wells, and all and the Tyrone Limestone. The Wells Creek the Ohio River. drill-cutting samples available from wells in Formation is the Wells Creek Dolomite in Stratigraphic studies show that the Black the area were used in the stratigraphic Kentucky. In Indiana, rocks underlying the River Group has eight marker beds in its characterization of the group. Black River are termed Chazyan and in- middle and upper portions and three dis- The Black River was sampled on a 1 -ft in- clude the Wells Creek of Ohio and Ken- tinct lithologic units in its lower portion; terval in the Adams and Brown County tucky and all or part of the lower argilla- these marker beds and units are present cores. X-ray diffraction analyses for calcite, ceous unit of this study. throughout southwestern Ohio. The Black dolomite, and quartz were run on 5-ft com- River Group correlates well with the High posites of these samples. Chemical analyses STRATIGRAPHY Bridge Group of Kentucky. Depositional were run on those zones indicated as high environments of the Black River are similar carbonate by the X-ray work on the Adams The lower third of the Black River Group to those of the High Bridge and to present- and Brown County cores. Atomic absorp- in Ohio is a mixture of micritic, burrowed, day tidal flats in the Bahamas. tion spectrophotometry was used for most and argillaceous limestones that can be di- of the analyses. All samples were analyzed vided into three units: upper and lower ar- INTRODUCTION for calcium, magnesium, silicon, aluminum, gillaceous limestones and pure limestone in iron, and potassium, and about one-half of the middle (Fig. 2). The basal unit of the Surface deposits of high-purity carbonate the samples were analyzed for sodium, Black River, the lower argillaceous unit, is rock are scarce in southwestern Ohio. Rock manganese, and strontium. All samples also made up of interbedded micrite, fine-

with greater than 95% CaC03 is termed were analyzed for sulfur and phosphorus. grained dolomite, argillaceous micrite, and high calcium, and rock with greater than shaly greenish limestone. All are laminated

95% total carbonates, CaC03 and GEOLOGIC SETTING in part. This unit is assigned to the Black

MgC03, is termed high carbonate. Al- River rather than to the underlying Wells though mining is generally more expensive The Black River Group in Ohio is not ex- Creek Formation primarily on the basis of than quarrying, the lack of surface deposits posed at the surface. It is shallowest in ex- lithology. Most of the limestone in this unit requires the consideration of possible sub- treme southwestern Ohio on the crest of the is essentially the same — micritic, pelletal, surface sources. The most likely possibility Cincinnati Arch. The Black River is 400 to fossiliferous, laminated, and argillaceous in in southwestern Ohio is the Middle Or- 500 ft of micritic and pelletal limestone, large part — as that in the argillaceous beds dovician Black River Group. The Black with some dolomitic and argillaceous and units higher in the Black River. River correlative, the High Bridge Group, is zones. It is overlain by the Trenton Lime- The lower argillaceous unit of the Black quarried in central Kentucky and is mined stone, a fine- to coarse-grained bioclastic River Group and the Wells Creek Forma- near Carntown and Maysville, Kentucky, limestone. In most places the Black River is tion are the units most affected by relief on along the Ohio River. underlain by the Wells Creek Formation, a the post-Knox unconformity surface. In

This article is based on a paper presented at a symposium entitled "Industrial Minerals of the Upper Midwest," held in April 1980.

Geological Society of America Bulletin, Part I, v. 92, p. 629-633, 3 figs., 1 table, September 1981.

629

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10 20 30 miles —L~i r1 1 r- "7- 10 20 30 kilometers I N LOGAN I SHELBY 2 UNION I " L i f - J I 14.%11 '"J 12 T-~ • I . _ • RANDOLPH 11 13* 10 64 I ' DARKE I CHAMPAIGN I 16 I- MIAMI •3 L_17_ ~1 9« 2 I r — 1 I I * i V R— CLARK MADISON WAYNE -L.J 3. Ì < I J 9 !o MONTGOMERY i PREBLE "I"" I— I GREENE

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* J J CAMPBEU^J r ADAMS AMENDER #1 (C) \ > I TZERLANDN \ J V—^ I M ,—- ^ !^tu8KV /"\ j ^ GALLATIN J „_---*6, 7(c) „„«„, I PENDLETON BRACKEN / N, I / GRANT \ OWEN / MASON 1 LEWIS

• well location

6 permit number of Ohio well; (c), core continuous through Black River Group Figure 1. Study area and well locations.

three wells, in Champaign, Clinton, and There are no known cores from wells with from 50 to 74 ft in thickness. In a few Highland Counties, this section is absent this particular lithology, and sample recov- localities, the Carntown is thin or absent because of highs that extend into the posi- ery was too poor in the ten wells to assign because of relief developed on the post- tion of overlying units. In approximately 10 an exact unit to the section. Knox unconformity surface. The top of the other wells, the entire lower argillaceous Overlying the lower argillaceous unit is Carntown unit is 320 to 400 ft below the unit-Wells Creek section is replaced by 10 the Carntown unit (Stith, 1979), a thick top of the Black River Group. to 50 ft of argillaceous dolomitic limestone section of very pure limestone and dolo- The uppermost unit in the lower third of that is difficult to assign to either unit. mitic limestone. The unit normally ranges the Black River Group is the upper argil-

Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/92/9/629/3419178/i0016-7606-92-9-629.pdf by guest on 03 October 2021 BOONE CO., KENTUCKY BENDER #1 laceous unit, which consists of micritic and pelletal limestone with a moderate amount of dolomite. The limestone and dolomite are dark colored and argillaceous in part, with partings and interbeds of dark-gray to TRENTON black shale and shaly limestone. LIMESTONE The middle third of the Black River Group is predominantly burrow-mottled micritic and pelletal limestone. This is the typical Camp Nelson lithology of the central Kentucky outcrop area. The burrows are dolomitized, and the matrix limestone is dolomitized in part. There are two marker beds in the middle third of the Black River that are about 95 to 120 ft apart; marker bed II is in the lower part of the section and marker bed I is at the top of the section. Marker bed II is 10 to 20 ft of burrowed micritic and pelletal limestone. It is dark colored and argillaceous in large part, with some carbonaceous shale and shaly limestone. Marker bed I is five to ten ft of interbedded argillaceous dark-colored micritic limestone and fine-grained dolomite, with sparse to moderate amounts of carbonaceous shale and shaly limestone. The upper third of the Black River Group is composed of interbedded micritic and pelletal limestone and fine-grained dolomite and, in general, correlates with the Tyrone BLACK Limestone and the Oregon Formation of Kentucky. In the upper third of the Black RIVER River Group are found six marker beds. Present at or near the base of the upper GROUP third are dolomitic beds equivalent to the Oregon. The rocks in the upper third of the Black River are argillaceous in part and laminated in part. Argillaceous material is concentrated mainly above marker b. Beds UPPER a and b are not recognized in all the logs in the study area. Marker beds a and b are ARGILLACEOUS generally bentonitic limestone or shale UNIT rather than distinct bentonites. Marker bed A is the thickest, 7 to 15 ft, of the upper 6 marker beds and is the only nonbentonitic one. This thick shaly-to-argillaceous limestone has a somewhat multifold character. CARNTOWN In most of the wells in the study area, the UNIT middle part of bed A is highly argillaceous and grades into slightly less argillaceous beds above and/or below. The three upper- LOWER most marker beds, a, (3, y, are all bentonites or, in a few places, mixtures of bentonitic ARGILLACEOUS shale and argillaceous limestone. UNIT • WELLS CREEK Figure 2. Representative nuclear log of FORMATION the Black River Group.

KNOX DOLOMITE

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Sample Sample Chemical analysis Calculations from

number interval CaO MgO Si02 AI2O3 Fe203 K2O Na20 SrO MnO S P chemical anlalyse s (ft) (%) (%) (%) (%) (%) (%) (%) (%) (ppm) (%) (%) CaCO, MgCO-) Insoluble T (%) (%) oxides (%)

ADAMS CO., MONROE TWP. S-2405 960-1009 48.2 4.85 2.21 0.50 0.26 0.25 0.08 0.003 86.0 10.14 3.17 1065-1134 50.1 3.48 1.94 0.44 0.17 0.16 0.07 0.002 89.5 7.28 2.69 1140-1179 51.2 2.55 1.77 0.53 0.21 0.22 0.08 0.002 91.4 5.33 2.70 1257-1317 50.8 3.30 1.07 0.31 0.19 0.14 0.023 0.032 50 0.08 0.002 90.8 6.91 1.72

BROWN CO., JACKSON TWP. S-2507 1035-1054 49.5 3.62 2.15 0.48 0.23 0.20 0.09 0.003 88.4 7.59 3.04 1090-1109 51.3 2.33 1.91 0.47 0.28 0.17 0.031 0.036 64 0.08 0.002 91.5 4.88 2.80 1140-1174 49.8 3.61 1.80 0.33 0.19 0.10 0.038 0.033 64 0.06 0.001 89.0 7.54 2.41 1200-1234 52.2 1.88 1.45 0.40 0.17 0.15 0.027 0.034 74 0.07 0.002 93.1 3.94 2.18 1310-1374 50.0 3.64 1.17 0.31 0.18 0.12 0.035 48 0.06 0.002 89.2 7.61 1.76

+ Note: Only analyses for zones greater than 15 feet thick were avei aged. Si02 a A1203 + (V2 • Fe203) + K20 + Na20 + S + P.

Figure 3. Elevation of top of the Carntown unit, Cincinnati, Ohio, vicinity.

WARREN

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10 miles Elevation below sea level Area of surface elevations less • Well location —100- p of Carntown unit of to than 600 feet above scia level 5 10 kilometers

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The change from micritic limestone of the DEPOSITIONAL ENVIRONMENTS tidal. Significant thicknesses of supratidal Black River Group to fossiliferous and intertidal rocks are found in the upper medium-to coarse-grained limestone of the Among the numerous papers on tidal sed- and lower argillaceous units and thinner Trenton Limestone occurs one to seven ft iments in the last 10 to 15 years have been sections in the Carntown unit in the Adams above marker bed a in all three cores. Ex- several on tidal environments in rocks of and Brown County cores. The lower argil- amination of sample cuttings and shorter Middle Ordovician age (Cressman and laceous unit and the Carntown unit are ab- cores from the other wells indicates that Noger, 1976; Mukherji, 1969; Walker, sent from the Highland County core be- marker bed a. in effect marks the Black 1973; Young and others, 1972). The pri- cause of nondeposition. River—Trenton contact throughout the mary general references on tidal environ- study area. ments used in this study are Ginsburg ACKNOWLEDGMENTS (1975) and Shinn and others (1969). CHEMICAL RESULTS The three full-length cores of the Black I would like to thank Richard S. Bow- River Group that make up the major part of man, Garland R. Dever, Jr., and Merrianne The chemical analyses of the Black River this study are nominal 2-in. cores (== 1%- Hackathorn for reviewing the manuscript. Group in the Adams and Brown County inch core diameter). Because of the core Leonard Guckenheimer and Adam Turk cores showed several zones of high- size, many of the diagnostic features of tidal provided cartographic assistance. carbonate rock of minable thickness environments such as channels, size of (Table 1). The first of these, between mud-crack polygons, and bedding con- marker beds b and I, includes the upper part tinuity cannot be determined accurately. REFERENCES CITED of the beds correlative to the Oregon For- However, enough features are present to mation and 10 to 15 ft of the overlying indicate that extensive supratidal and inter- Cressman, E. R., and Noger, M. C., 1976, rock. This zone is almost 97% total car- tidal environments are represented in the Tidal-Hat carbonate environments in the bonate (3% to 3.2% insoluble oxides). The Black River carbonates in southwestern High Bridge Group (Middle Ordovician) of central Kentucky: Kentucky Geological rocks in the middle third of the Black River Ohio. The Black River Group is most simi- Survey, ser. X, Report of Investigations 18, contain one or two zones of high-carbonate lar to Middle Ordovician rocks in central 15 p. rock between marker beds 1 and II and an- Kentucky (Cressman and Noger, 1976) and Ginsburg, R. N., ed., 1975, Tidal deposits, a other zone immediately below marker bed New York (Walker, 1973) and to recent casebook of Recent examples and fossil II. These zones are between 97% and 98% sediments in the Bahamas (Shinn and counterparts: New York, Springer-Verlag, 428 p. total carbonate. The purest rock in the others, 1969). Mukherji, K. K., 1969, Supratidal carbonate Black River is the Carntown unit. Basically, Supratidal features most commonly rocks in the Black River (Middle Ordovi- the entire unit in the two cores is over 98% found are laminated and interlaminated cian) Group of southwestern Ontario, Canada: Journal of Sedimentary Petrology, total carbonate. micrite and dolomite, mud cracks, both v. 39, p. 1530-1545. Although no appreciable thicknesses of planar and nonplanar bird's-eye fabric Shinn, E. A., Lloyd, R. M., and Ginsburg, R. N., high-calcium stone were found in the two (fenestral pores), and sheet cracks. No evi- 1969, Anatomy of a modern carbonate cores, examination of geophysical logs in dence of evaporites such as crystal molds or tidal-flat, Andros Island, Bahamas: Journal the study area indicates its possible pres- collapse breccia was found, lntertidal facies of Sedimentary Petrology, v. 39, p. 1202- 1228. ence. The neutron logs of 4 wells, 1 in were the most difficult to recognize in the Stith, D. A., 1979, Chemical composition, Clermont County, 2 in Butler County, and narrow-diameter core. Vertical and U - stratigraphy, and depositional environ- 1 in Miami County, indicate 15 to 45 ft of shaped burrows were considered the most ments of the Black River Group (Middle very low dolomite rock in the Carntown reliable indicators. Much of the laminated Ordovician), southwestern Ohio: Ohio unit. The logs also show that, in general, micrite showing reduced numbers, small Geological Survey Report of Investigations 113, 36 p. dolomite is concentrated in the upper one- size, and faintness of desiccation features Walker, K. R., 1973, Stratigraphy and environ- quarter and lower one-half of the Carn- such as bird's-eyes and laminations was mental sedimentology of Middle Ordovi- town unit. also considered indicative of intertidal dep- cian Black River Group in the type area — Figure 3 shows the southwestern corner osition because of the common association New York State: New York State Museum of these features with vertical burrows. and Science Service Bulletin 419, 43 p. of the study area. The structure contours Young, L. M., Fiddler, L. C., and Jones, R. W., are on the top of the Carntown unit. The Subtidal environments are shown by a gen- 1972, Carbonate facies in Ordovician of shaded area represents land elevations in erally large and diverse marine fauna in the northern Arkansas: American Association Ohio less than 600 ft above sea level along fossiliferous micrites. In addition, many of of Petroleum Geologists Bulletin, v. 56, p. 68-80. the Miami, Little Miami, and Ohio Rivers. these rocks show horizontal burrows. The hachured area is Cincinnati. U.S. In all cores examined, one-third to two- Geological Survey flood-prone area maps of thirds of the rocks above marker bed I are the Cincinnati vicinity show elevations of of supratidal and intertidal facies. Most of 500 to 520 ft as flood-susceptible. For a the section between marker beds I and II is mine entry sited between 550 and 600 ft horizontally burrowed subtidal rock. In all MANUSCRIPT RECEIVED BY THE SOCIETY MARCH elevation, depth to the top of the Carntown three main cores the first few feet of rock 27, 1981 unit would be 625 to 850 ft. immediately below marker bed II are inter- MANUSCRIPT ACCEPTED APRIL 7, 1981

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