USGS I-Map 2495 - Map Text

Stratigraphic Framework of Cambrian and Ordovician Rocks in the Central Appalachian Basin From Fayette County, Ohio, to Botetourt County, Virginia

Robert T. Ryder, John E. Repetski, and Anita G. Harris,
1996,
U. S. Geological Survey Map Series I-2495

DISCUSSION [ Top ]

INTRODUCTION

Cross section F-F` is the fifth in a series of restored stratigraphic cross sections drawn by the senior author to show the stratigraphic framework of Cambrian and Ordovician rocks in the Appalachian basin from Pennsylvania to Tennessee. These sections show complexly intertongued carbonate and siliciclastic lithofacies, marked thickness variations, key marker horizons, unconformities, and stratigraphic nomenclature of the Cambrian and Ordovician sequence. Several of the drill holes along the cross sections have yielded a variety of whole and (or) fragmented conodont elements. The identifiable conodonts are used to differentiate strata of Middle Cambrian, Late Cambrian, and Early Ordovician age, and their conodont color alteration index (CAI) values are used to establish the thermal maturity of the sequence. Macrofossil collections from drill holes and (or) outcrop sections along the restored sections provide additional biostratigraphic data. In addition to providing lithologic, nomenclatural, and paleontologic details of Cambrian and Ordovician strata, these cross sections also help to define and delineate the structure of the block-faulted Proterozoic basement rocks beneath the sedimentary cover of the Appalachian basin. Previously completed cross sections in this series are cross section E-E` (Ryder, 1992a), cross section D-D` (Ryder, 1991), cross section C-C` (Ryder and others, 1992), and cross section B-B` (Ryder, 1992b) (fig. 1).

Section F-F` is about 285 mi (459 km) long. The section is constructed on the basis of eleven drill holes that are from 9 to 102 mi (14-164 km) apart and range in depth from 1,970 to 19,124 ft (600-5,829 m) (fig.1, table 1). Seven of the eleven drill holes bottomed in crystalline basement rocks of Middle Proterozoic age. Drill holes 9, 10, and 11, which are located east of the St. Clair thrust fault (fig.1), were restored 13 to 21 mi (21-34 km) southeastward to compensate for tectonic transport along underlying Alleghanian thrust faults (Woodward and Gray, 1985; Kulander and Dean, 1986).

METHODOLOGY AND STRATIGRAPHIC NOMENCLATURE

Borehole geophysical logs were used to establish most of the correlations between drilled stratigraphic units in section F-F`. In drill holes 9 and 10, where geophysical logs were not obtained, correlations between drilled stratigraphic units are based primarily on lithology. Lithologic logs, produced by the Geological Sample Log Company (Pittsburgh, Pa.) and other sources, are used to establish the lithofacies in and between the drill holes. The drilled Cambrian and Ordovician sequence at the southeastern end of section F-F` (drill holes 9 and 10) was supplemented by measured outcrop sections reported by Lesure (1957), Whitman (1964), Rader and Ryan (1965), Chen (1981), and McDowell and Schultz (1990).

Section F-F` has been restored to a horizontal datum located at the base of a widespread 60- to 90-ft (18- to 27-m)-thick micritic limestone located at or near the base of the Black River Group in southern Ohio and adjoining West Virginia and near the base of the Blackford Formation, Elway Limestone, Five Oaks Limestone, and Peery Limestone, undivided, in southwestern Virginia and adjoining West Virginia. This micritic limestone was selected as the datum horizon for section F-F` because it appears to be the most widespread and easily recognizable subsurface and surface marker unit in the Cambrian and Ordovician sequence of the central Appalachian basin. Metabentonite beds in the Black River Group also are good marker units.

Much of the stratigraphic nomenclature used in section F-F` follows the nomenclature used by Ryder (1992a) in adjoining section E-E`. The reader is referred to that paper for a more detailed discussion of Cambrian and Ordovician stratigraphy in eastern Ohio and central West Virginia. Existing nomenclature established by the State Geological Surveys of Ohio, Virginia, and West Virginia is preferred here, but in certain places modifications and additions are recommended. At some localities in section F-F`, footnotes clarify the use of specific stratigraphic terms. The following stratigraphic investigations are particularly applicable to this investigation: (1) Janssens (1973), Stith (1979, 1986), and Shrake and others (1990) in Ohio; (2) Cable and Beardsley (1984), Patchen and others (1984), and Donaldson and others (1988) in West Virginia; and (3) Cooper (1945), Read (1980), and Rader (1982) in Virginia.

The correlation chart (fig.2) shows the chronostratigraphic position and nomenclature of Cambrian and Ordovician units identified in selected tectonic provinces along F-F`. Moreover, this chart compares the nomenclature and chronostratigraphic position of Cambrian and Ordovician units in section F-F` with those in the adjoining Pulaski thrust sheet in eastern Botetourt County, Va. (Henika, 1981; Rader, 1982).

European chronostratigraphic units (for example, Tremadocian through Ashgillian Stages) commonly do not apply to the cratonal and platformal Ordovician rocks of North America (Ross and others, 1984). Therefore, in this paper we apply North American chronostratigraphic units used by Barnes and others (1981) and Ross and others (1982) rather than the European chronostratigraphic units used by Palmer (1983) and the Correlation of Stratigraphic Units of North America (COSUNA) (for example, see Patchen and others, 1984). Our correlation chart (fig.2) subdivides the Ordovician System into the Lower, Middle, and Upper North American Series of Barnes and others (1981) and equates them with the Ibexian, Whiterockian and Mohawkian combined, and Cincinnatian Series of Ross and others (1982), respectively. In addition, because of its well-established usage in North America, the Canadian Series of Barnes and others (1981) is shown as being equivalent to the Ibexian Series of Ross and others (1982).

The Blackriveran through Gamachian(?) Stages of the Ordovician (fig.2) follow the definitions of Barnes and others (1981) and Ross and others (1982). The Chazyan as used by Barnes and others (1981) is retained in this paper as a formal stage because of its long-time usage in North America. In contrast, Ross and others (1982) recognize the Chazyan as a chronostratigraphic unit of historical interest rather than a formal stage of the Ordovician System.

CONODONT BIOSTRATIGRAPHY AND AGE OF THE COPPER RIDGEAND BEEKMANTOWN DOLOMITES

Identifiable conodonts were recovered from 8 of the 24 samples collected between the depths of 253 and 2,998 ft (77-914 m) in the Joy Manufacturing Company corehole WVAC-1 (f₁ on cross section,table 2). Judging from these conodonts and lithologic character, the top part of the core consists of the Lower Ordovician part of the Beekmantown Dolomite and the bottom of the core consists of undefined limestone and dolomite of Middle Ordovician age. According to a preliminary core description by ARCO geologists (unpub. data, 1985), the core is cut by multiple faults, of which the most easily identified is at 1,800 ft (549 m). The description further notes that the Copper Ridge Dolomite was not sampled by the core.

Conodonts recovered at the depths of 253, 404, 490, 1,550, 2,011, and 2,605 ft (77, 123, 149, 472, 613, and 794 m) are Early Ordovician in age, whereas the conodonts recovered at the depths of 2,950 and 2,998 ft (899 and 914 m) are Middle Ordovician in age (table 2). The inverted stratigraphy has resulted from the numerous thrust faults that cut the core. In addition to the fault at 1,800 ft (549 m), faults are interpreted to cut the core between the depths of 490 and 1,550 ft (149-472 m) and between the depths of 2,605 and 2,950 ft (794-899 m). These faults probably merge with the underlying St. Clair thrust fault. The fault between the depths of 490 and 1,550 ft (149-472 m) is proposed here to reduce the thickness of the Lower Ordovician part of the Beekmantown Dolomite in the corehole to the approximate 1,000-ft (305-m) thickness of equivalent strata observed in Giles County, Va. (Bartholomew, 1987).

In the Joy Manufacturing Company corehole VAC-4, identifiable conodonts were recovered from 11 of the 23 samples collected between the depths of 64 and 1,550 ft (20-472 m) (f₂ on cross section, table 3). Judging from these conodonts and lithologic character, the top part of the core consists of undefined limestone of Middle Ordovician age and the middle and lower parts of the core probably consist largely of the Lower Ordovician part of the Beekmantown Dolomite. According to a preliminary core description by I.P. Montaatnez (University of California, Riverside, unpub. data, 1985), the Knox unconformity is located between the depths of 279 and 281 ft (85 m). Conodonts recovered from the core at depths of 105, 195, and 258 ft (32, 59, and 79 m) are Middle Ordovician in age, whereas conodonts recovered at depths of 456, 701, 850, 966, 1,129, 1,215, 1,370, and 1,409 ft (139, 214, 259, 293, 344, 370, 418, and 429 m) are Early Ordovician in age (table 3). The distribution of these conodonts supports the position of the Knox unconformity as noted by Montanez (University of California, Riverside, unpub. data, 1985).

The dolomite unit that directly underlies the Knox unconformity in Alleghany County, Va., has been named the Beekmantown Dolomite by Lesure (1957). The thickness of the Beekmantown Dolomite was not established by Lesure (1957) because only the upper few hundred feet of the unit are exposed. The 1,270-ft (387-m)-thick dolomite interval in the Joy Manufacturing Company VAC-4 corehole between the Knox unconformity and the bottom of the core, over which Lower Ordovician conodonts occur, represents the approximate thickness of the Beekmantown Dolomite in Alleghany County. This thickness is consistent with the 1,600-ft (488-m) thickness of the Lower Ordovician part of the Beekmantown Group at the eastern end of section E-E` (Ryder, 1992a) and with the 1,000-ft (305-m) thickness of the equivalent undivided upper part of the Knox Group in Giles County, Va. (Bartholomew, 1987).

The identified conodonts from the Joy Manufacturing Company WVAC-1 and VAC-4 coreholes support the stratigraphic studies by Butts (1940), Cooper (1944), and Mussman and Read (1986) and the conodont studies by Harris and Repetski (1982, 1983) where the Knox unconformity throughout southwestern and central Virginia was defined by limestone of early Middle Ordovician (Chazyan) age resting disconformably on the Beekmantown Group (Dolomite) of Early Ordovician age.

The Beekmantown Dolomite in the Joy Manufacturing Company WVAC-1 and VAC-4 coreholes is probably underlain by a 100- to 200-ft (30- to 61-m)-thick sandstone and dolomite sequence that correlates with (1) a sandstone and dolomite sequence in Pendleton County, W. Va., at the eastern end of section E-E` that is recognized as either the upper sandy member of the Upper Cambrian Gatesburg Formation (Ryder, 1992a) or the upper part of the Upper Cambrian Copper Ridge Dolomite (Perry, 1964) and (2) a sandstone and dolomite sequence in Giles County, Va., that is recognized as either the upper part of the Upper Cambrian Copper Ridge Dolomite (Bartholomew, 1987) or the lower part of the Lower Ordovician Chepultepec Dolomite (Perry and others, 1979; Schultz and others, 1986). For reasons discussed in the following paragraphs, we recommend that the inferred sandstone and dolomite sequence be included with the Copper Ridge Dolomite.

The Lower Ordovician Chepultepec Dolomite of the Knox Group is a widely accepted unit in eastern Tennessee (Rodgers, 1953) and in adjoining southwestern Virginia (Miller and Fuller, 1954; Harris and Miller, 1963). There, the Chepultepec Dolomite consists of a lower sandstone and dolomite unit and an upper dolomite unit. Cooper (1971), Perry and others (1979), and Schultz and others (1986) extend the Chepultepec Dolomite northeastward, with the lower sandstone and dolomite unit intact, into Giles County, Va. In contrast, Bartholomew (1987) prefers to map the lower sandstone and dolomite unit of the Chepultepec-equivalent strata in Giles County with the underlying Copper Ridge Dolomite and the upper dolomite unit of the Chepultepec-equivalent strata with undivided strata of the overlying upper part of the Knox Group.

We agree with Bartholomew (1987) that the upper dolomite unit of the Chepultepec Dolomite cannot be differentiated from strata in the overlying upper part of the Knox Group in Giles County. Consequently, the Chepultepec Dolomite probably is not a valid stratigraphic term in Giles County, and the mappable sandstone and dolomite unit that is equivalent to the lower part of the Chepultepec Dolomite is more appropriately combined with the Copper Ridge Dolomite. However, the Late Cambrian and Early Ordovician(?) conodonts reported by Perry and others (1979) from their Chepultepec Dolomite-upper sandstone-bearing part of the Copper Ridge Dolomite of Bartholomew (1987)-in the California Company No. 1 Strader drill hole, central Giles County, requires that the widely accepted Late Cambrian age of the Copper Ridge Dolomite be modified to a Late Cambrian and Early Ordovician(?) age.

BASEMENT STRUCTURE

Details of the structural configuration of block-faulted Middle Proterozoic basement rocks underlying the Appalachian basin in West Virginia are poorly understood because (1) few drill holes have penetrated the sedimentary cover, (2) few magnetic and gravity data have been calibrated to known basement rock types and structures, and (3) very few seismic profiles have been published. Because the basement faults accompanying section F-F` are based on limited data and, thus, are highly conjectural, they are shown on figure 1 as 25- to 100-mi (40- to 161-km)-long, incomplete line segments.

The northeast-trending, fault-controlled Rome trough is recognized as a dominant element of basement structure in West Virginia (Cardwell, 1977; Harris, 1978; Beardsley and Cable, 1983; Cable and Beardsley, 1984; Shumaker, 1986; Read, 1989). On section F-F`, the Rome trough is shown as a conspicuous graben system in which Middle Proterozoic rocks of the Grenville orogenic belt have been downdropped 6,000 to 7,000 ft (1,829-2,134 m) along bounding normal faults. The north side of the graben is flanked by the Ohio-West Virginia hinge zone of Ryder (1992a) (Middle Cambrian hinge of Read, 1989) whereas the south side is flanked by the Southern West Virginia arch of Kulander and Dean (1978, 1986).

The basement-involved normal faults that bound the Rome trough and the intratrough depression on section F-F` are based on previous structural interpretations (Cable and Beardsley, 1984; Shumaker, 1986; Lowry and others, 1990) and several published seismic profiles (Lee, 1980; Wallace and others, 1986). The minor normal faults on section F-F` that offset the basement rocks of the Ohio-West Virginia hinge zone are based largely on abrupt thickness changes in drilled Cambrian strata. The Southern West Virginia arch and the contiguous Central West Virginia arch (Kulander and Dean, 1978, 1986) are expressed as positive anomalies on magnetic and gravity maps (Kulander and Dean, 1978; Zietz and others, 1980; Kulander and others, 1987). These magnetic and gravity anomalies define the West Virginia part of the New York-Alabama lineament of King and Zietz (1978). Block-faulted terrane southeast of the Southern West Virginia arch, shown on section F-F`, is interpreted from magnetic data of Zietz and others (1980), seismic data of Gresko (1985), and epicenter data of Bollinger and Wheeler (1988).

The abrupt change in lithology of the Middle Proterozoic basement rocks from metasedimentary and metavolcanic rocks in the Kewanee Oil Company No. 1 Hopkins drill hole to granitic rocks in the Crest Oil Company No. 1 Clark drill hole suggests a major fault between these drill holes that preceded the deposition of the Mount Simon Sandstone. This proposed fault is probably an east-dipping thrust fault near the western margin of the Grenville orogenic belt, similar to those interpreted from the Ohio COCORP (Consortium for Continental Reflection Profiling) seismic lines by Culotta and others (1990).

Younger normal faults that were active during the deposition of the Upper Cambrian Mount Simon Sandstone have not been identified on section F-F`. Probably those syndepositional faults are present but their offset is too small to be detected by thickness changes in the drilled Mount Simon Sandstone. Near the western end of section F-F`, basement rocks have been uplifted into a broad, south-plunging arch that was named the Waverly arch by Woodward (1961).

REFERENCES CITED [ Top ]

Barnes, C.R., Norford, B.S., and Skevington, David, 1981, The Ordovician System in Canada, correlation chart and explanatory notes: International Union of Geological Sciences Publication 8, 27 p.

Bartholomew, M.J., 1987, Structural evolution of the Pulaski thrust system, southwestern Virginia: Geological Society of America Bulletin, v. 99, no. 4, p. 491-510.

Beardsley, R.W., and Cable, M.S., 1983, Overview of the evolution of the Appalachian basin: Northeastern Geology, v. 5, no. 3/4, p. 137-145.

Bergstrom, S.M., and Mitchell, C.E., 1989, Relations between the Ordovician Trenton Group and associated strata in the northern Appalachian foreland basin-shelf region and their lateral equivalents in the eastern midcontinent, in Shumaker, R.C., comp., Appalachian Basin Industrial Associates, v. 15, Spring Program [April 1989]: Morgantown, West Virginia University, p. 7-41.

Bollinger, G.A., and Wheeler, R.L., 1988, The Giles County, Virginia, seismic zone- Seismological results and geological interpretations: U.S. Geological Survey Professional Paper 1355, 85 p.

Butts, Charles, 1940, Geology of the Appalachian Valley in Virginia, pt. I: Virginia Geological Survey Bulletin 52, 568 p.

Cable, M.S., and Beardsley, R.W., 1984, Structural controls on Late Cambrian and Early Ordovician carbonate sedimentation in eastern Kentucky: American Journal of Science, v. 284, no. 7, p. 797-823.

Calvert, W.L., 1964, Cambrian erosional remnants yield oil in central Ohio: World Oil, v. 158, no. 4, p. 78, 80, 82, 84.

Cardwell, D.H., 1977, West Virginia gas development in Tuscarora and deeper formations (with structural maps contoured on top of Ordovician and Precambrian): West Virginia Geological and Economic Survey Mineral Resources Series 8, 34 p.

Chen, Ping-fan, 1981, Lower Paleozoic stratigraphy, tectonics, paleogeography, and oil/gas possibilities in the central Appalachians (West Virginia and adjacent states), Part 2, Measured sections: West Virginia Geological and Economic Survey Report of Investigation No. RI-26-2, 300 p.

Cooper, B.N., 1944, Geology and mineral resources of the Burkes Garden quadrangle, Virginia: Virginia Geological Survey Bulletin 60, 299 p.

_____1945, Industrial limestones and dolomites in Virginia, Clinch Valley District: Virginia Geological Survey Bulletin 66, 259 p.

_____1961, Grand Appalachian excursion: Virginia Polytechnic Institute Engineering Extension Series, Geological Guidebook 1, 187 p.

_____1971, The Appalachian structural and topographic front between Narrows and Beckley, Virginia and West Virginia, in Guidebook to Appalachian tectonics and sulfide mineralization of southwestern Virginia: Blacksburg, Virginia Polytechnic Institute and State University, Department of Geological Sciences, Guidebook no. 5, p. 87-142.

Cooper, B.N., and Prouty, C.E., 1943, Stratigraphy of the lower Middle Ordovician of Tazewell County, Virginia: Geological Society of America Bulletin, v. 54, no. 6, p. 819-886.

Culotta, R.C., Pratt, T., and Oliver, J., 1990, A tale of two sutures: COCORP's deep seismic survey of the Grenville province in the eastern U.S. midcontinent: Geology, v. 18, no. 7, p. 646-649.

Donaldson, Alan, Heald, Milton, and Warshauer, Steven, 1988, Cambrian rocks of the Rome trough in West Virginia: Cores from Mingo and Wayne Counties, in Smosna, Richard, organizer, A walk through the Paleozoic of the Appalachian basin: American Association of Petroleum Geologists Eastern Section Meeting, Charleston, West Virginia, p. 6-18.

Epstein, A.G., Epstein, J.B., and Harris, L.D., 1977, Conodont color alteration-An index to organic metamorphism: U.S. Geological Survey Professional Paper 995, 27 p.

Ethington, R.L., and Clark, D.L., 1981, Lower and Middle Ordovician conodonts from the Ibex area, western Millard County, Utah: Brigham Young University Geology Studies, v. 28, pt. 2, 155 p.

Gibbons, A.B., and Weiss, M.P., 1972, Geologic map of the Maysville West quadrangle, Kentucky-Ohio: U.S. Geological Survey Geologic Quadrangle Map GQ-1005, scale 1:24,000.

Gresko, M.J., 1985, Analysis and interpretation of compressional (P-wave) and shear (SH-wave) reflection seismic and geologic data over the Bane dome, Giles County, Virginia: Blacksburg, Virginia Polytechnic Institute and State University, Ph.D. dissertation, 74 p.

Harris, A.G., and Repetski, J.E., 1982, Conodonts revise the Lower-Middle Ordovician boundary and timing of miogeoclinal events in the east-central Appalachian basin [abs.]: Geological Society of America Abstracts with Programs, v. 14, no. 5, p. 261.

_____1983, Conodonts document continuous to intermittent deposition across the Lower-Middle Ordovician boundary-Northern Virginia to Bellefont (sic), PA [abs.]: The Virginia Journal of Science, v. 34, no. 3, p. 172.

Harris, L.D., 1978, The eastern interior aulacogen and its relation to Devonian shale-gas production, in Second eastern gas shales symposium, v. II: Morgantown, West Virginia, U.S. Department of Energy, Morgantown Energy Technology Center, p. 56-72.

Harris, L.D., and Miller, R.L., 1963, Geology of the Stickleyville quadrangle, Virginia: U.S. Geological Survey Geologic Quadrangle Map GQ-238, scale 1:24,000.

Henika, W.S., 1981, Geology of the Villamont and Montvale quadrangles, Virginia: Virginia Division of Mineral Resources Publication 35, 18 p., 1 map, scale 1:24,000.

Huff, W.D., 1983, Correlation of Middle Ordovician K-bentonites based on chemical fingerprinting: Journal of Geology, v. 91, no. 6, p. 657-669.

Huff, W.D., and Kolata, D.R., 1990, Correlation of the Deicke and Millbrig K-bentonites between the Mississippi Valley and southern Appalachians: American Association of Petroleum Geologists Bulletin, v. 74, no. 11, p. 1736-1747.

Janssens, Adriaan, 1973, Stratigraphy of the Cambrian and Lower Ordovician rocks in Ohio: Ohio Division of Geological Survey Bulletin 64, 197 p.

_____1977, Silurian rocks in the subsurface of northwestern Ohio: Ohio Division of Geological Survey Report of Investigations 100, 96 p.

King, E.R., and Zietz, Isidore, 1978, The New York-Alabama lineament: Geophysical evidence for a major crustal break in the basement beneath the Appalachian basin: Geology, v. 6, no. 5, p. 312-318.

Kulander, B.R., and Dean, S.L., 1978, Gravity, magnetics and structure, Allegheny Plateau/western Valley and Ridge in West Virginia and adjacent states: West Virginia Geological and Economic Survey Report of Investigation RI-27, 91 p., 3 sheets, scale 1:250,000.

_____1986, Structure and tectonics of central and southern Appalachian Valley and Ridge and Plateau provinces, West Virginia and Virginia: American Association of Petroleum Geologists Bulletin, v. 70, no. 11, p. 1674-1684.

Kulander, B.R., Dean, S.L., and Hodge, D.S., 1987, Bouguer gravity map of West Virginia: West Virginia Geological and Economic Survey Map WV 25, 2 sheets, scale 1:250,000.

Lee, K.D., 1980, Subsurface structure of the eastern Kentucky gas field: Morgantown, University of West Virginia, M.S. thesis, 53 p.

Lesure, F.G., 1957, Geology of the Clifton Forge iron district, Virginia: Virginia Polytechnic Institute Bulletin, Engineering Experimental Station Series No. 118, v. 50, no. 7, 130 p., 1 map, scale 1:31,680.

Lowry, P.H., Hamilton-Smith, Terence, and Falleur, J.P., 1990, Structural and lithofacies mapping provide tools for exploration in Devonian shales: Devonian Gas Shales Technology Review, v. 6, nos. 2 and 3, p. 46-61.

Markello, J.R., and Read, J.F., 1982, Upper Cambrian intrashelf basin, Nolichucky Formation, southwest Virginia Appalachians: American Association of Petroleum Geologists Bulletin, v. 66, no. 7, p. 860-878.

McDowell, R.C., 1983, Stratigraphy of the Silurian outcrop belt on the east side of the Cincinnati arch in Kentucky, with revisions in the nomenclature: U.S. Geological Survey Professional Paper 1151-F, 27 p.

McDowell, R.C., and Schultz, A.P., 1990, Structural and stratigraphic framework of the Giles County area, a part of the Appalachian basin of Virginia and West Virginia: U.S. Geological Survey Bulletin 1839-E, p. E1-E24, 1 map, scale 1:125,000.

Miller, R.L., and Fuller, J.O., 1954, Geology and oil resources of the Rose Hill District- The fenster area of the Cumberland overthrust block-Lee County, Virginia: Virginia Geological Survey Bulletin 71, 383 p.

Mussman, W.J., and Read, J.F., 1986, Sedimentology and development of a passive- to convergent-margin unconformity: Middle Ordovician Knox unconformity, Virginia Appalachians: Geological Society of America Bulletin, v. 97, no. 3, p. 282-295. O' Brien, M.H., 1970, Correlation chart Silurian System, in Silurian stratigraphy, central Appalachian basin: Charleston, West Virginia, Appalachian Geological Society, p. 1.

Palmer, A.R., comp., 1983, Decade of the North American Geology 1983 time scale: Geology, v. 11, no. 9, p. 503-504.

Patchen, D.G., Avary, K.L., and Erwin, R.B., coordinators, 1984, Correlation of stratigraphic units of North America (COSUNA) Project, northern Appalachian region correlation chart: Tulsa, Okla., American Association of Petroleum Geologists, 1 sheet.

Peck, J.H., 1966, Upper Ordovician formations in the Maysville area, Kentucky: U.S. Geological Survey Bulletin 1244-B, p. B1-B30.

Pepper, J.F., de Witt, Wallace, Jr., and Everhart, G.M., 1953, The |P`Clinton sands in Canton, Dover, Massillon, and Navarre quadrangles, Ohio: U.S. Geological Survey Bulletin 1003-A, 15 p.

Perry, W.J., Jr., 1964, Geology of Ray Sponaugle well, Pendleton County, West Virginia: American Association of Petroleum Geologists Bulletin, v. 48, no. 5, p. 659-669.

Perry, W.J., Jr., Harris, A.G., and Harris, L.D., 1979, Conodont-based reinterpretation of Bane dome-Structural reevaluation of Allegheny frontal zone: American Association of Petroleum Geologists Bulletin, v. 63, no. 4, p. 647-654.

Rader, E.K., 1982, Valley and Ridge stratigraphic correlations, Virginia: Virginia Division of Mineral Resources Publication 37, 1 sheet.

Rader, E.K., and Ryan, J.J., 1965, Martinsburg Formation in west-central Virginia: Virginia Division of Mineral Resources Virginia Minerals, v. 11, p. 32-34.

Read, J.F., 1980, Carbonate ramp-to-basin transitions and foreland basin evolution, Middle Ordovician, Virginia Appalachians: American Association of Petroleum Geologists Bulletin, v. 64, no. 10, p. 1575-1612.

_____1989, Evolution of Cambro-Ordovician passive margin, U.S. Appalachians, in Rankin, D.W., Drake, A.A., Jr., Glover, L., III, Goldsmith, R., Hall, L.M., Murray, D.P., Ratcliffe, N.M., Read, J.F., Secor, D.T., Jr., and Stanley, R.S., Pre-orogenic terranes, in Hatcher, R.D., Jr., Thomas, W.A., and Viele, G.W., eds., The Appalachian-Ouachita orogen in the United States: Boulder, Colorado, Geological Society of America, The Geology of North America, v. F-2, p. 42-57.

Rodgers, John, 1953, Geologic map of east Tennessee with explanatory text: Tennessee Division of Geology Bulletin 58, pt. 2, 168 p., 15 pls.

Ross, R.J., Jr., Adler, F.J., Amsden, T.W., Bergstr|$$|Adom, Douglas, Bergstr|$$|Adom, S.M., Carter, Claire, Churkin, Michael, Cressman, E.A., Derby, J.R., Dutro, J.T., Jr., Ethington, R.L., Finney, S.C., Fisher, D.W., Fisher, J.H., Harris, A.G., Hintze, L.F., Ketner, K.B., Kolota, D.L., Landing, Ed, Newman, R.B., Sweet, W.C., Pojeta, John, Jr., Potter, A.W., Rader, E.K., Repetski, J.E., Shaver, R.H., Thompson, T.L., and Webers, G.F., 1982, The Ordovician System in the United States: International Union of Geological Sciences Publication 12, 73 p.

Ross, R.J., Jr., Bergstr|$$|Adom, S.M., and Derby, J.R., 1984, Comment and reply on |P`The Decade of North American Geology 1983 geologic time scale: Geology, v. 12, no. 8, p. 505-506.

Ryder, R.T., 1991, Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian basin from Richland County, Ohio, to Rockingham County, Virginia: U.S. Geological Survey Miscellaneous Investigations Series Map I-2264.

_____1992a, Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian basin from Morrow County, Ohio, to Pendleton County, West Virginia: U.S. Geological Survey Bulletin 1839-G, p. G1-G25, 1 pl.

_____1992b, Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian basin from Lake County, Ohio, to Juniata County, Pennsylvania: U.S. Geological Survey Miscellaneous Investigations Series Map I-2200.

Ryder, R.T., Harris, A.G., and Repetski, J.E., 1992, Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian basin from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, West Virginia: U.S. Geological Survey Bulletin 1839-K, p. K1-K32, 1 pl.

Schultz, A.P., Stanley, C.B., Gathright, T.M., II, Rader, E.K., Bartholomew, M.J., Lewis, S.E., and Evans, N.H., 1986, Geologic map of Giles County, Virginia: Virginia Division of Mineral Resources Publication 69, 1 sheet, scale 1:50,000.

Schumacher, G.A., and Carlton, R.W., 1991, Impure K-bentonite beds from the Lexington Limestone and the Point Pleasant Formation (Middle Ordovician) of northern Kentucky and southwestern Ohio: Southeastern Geology, v. 32, no. 2, p. 83-105.

Schumacher, G.A., Swinford, E.M., and Shrake, D.L., 1991, Lithostratigraphy of the Grant Lake Limestone and Grant Lake Formation (Upper Ordovician) in southwestern Ohio: Ohio Journal of Science, v. 91, no. 1, p. 56-68.

Shrake, D.L., Wolfe, P.J., Richard, B.H., Swinford, E.M., Wickstrom, L.H., Potter, P.E., and Sitler, G.W., 1990, Lithologic and geophysical description of a continuously cored hole in Warren County, Ohio, including description of the Middle Run Formation (Precambrian?) and a seismic profile across the site: Ohio Division of Geological Survey Information Circular No. 56, 11 p., 2 pls.

Shumaker, R.C., 1986, The effect of basement structure on sedimentation and detached structural trends within the Appalachian basin, in McDowell, R.C., and Glover, Lynn, III, eds., The Lowry Volume: Studies in Appalachian geology: Virginia Polytechnic Institute and State University Department of Geologic Sciences Memoir 3, p. 67-81.

Stith, D.A., 1979, Chemical composition, stratigraphy, and depositional environments of the Black River Group (Middle Ordovician), southwestern Ohio: Ohio Division of Geological Survey Report of Investigations 113, 36 p., 3 pls.

_____1986, Supplemental core investigations for high-calcium limestones in western Ohio and discussion of natural gas and stratigraphic relationships in the Middle to Upper Ordovician rocks of southwestern Ohio: Ohio Division of Geological Survey Report of Investigations 132, 17 p., 3 pls.

Wallace, J.L., Koziar, G., Lemon, J.P., and Akers, M.J., Jr., 1986, Devonian shale gas exploration and production studies: Gas Research Institute Report 86/1040, contract no. 5083-213-0856, Chicago, Illinois, 77 p.

Weir, G.W., Peterson, W.L., Swadley, W.C., and Pojeta, John, Jr., 1984, Lithostratigraphy of Upper Ordovician strata exposed in Kentucky: U.S. Geological Survey Professional Paper 1151-E, 121 p., 5 pls.

Weiss, M.P., Schilling, F.A., Pierce, K.L., and Ali, S.A., 1972, Geologic map of the Maysville East quadrangle, Ohio-Kentucky: U.S. Geological Survey Geologic Quadrangle Map GQ-1006, scale 1:24,000.

Whitman, H.M., 1964, Geology of the Pearis Mountain area, Virginia: Blacksburg, Virginia Polytechnic Institute and State University, M.S. thesis, 91 p.

Wilson, J.L., 1952, Upper Cambrian stratigraphy in the central Appalachians: Geological Society of America Bulletin, v. 63, no. 3, p. 275-322.

Woodward, H.P., 1961, Preliminary subsurface study of southeastern Appalachian Interior Plateau: American Association of Petroleum Geologists Bulletin, v. 45, no. 10, p. 1634-1655.

Woodward, N.B., and Gray, D.R., 1985, Chapter III-Southwest Virginia, Tennessee, and northern Georgia sections, in Woodward, N.B., ed., Valley and Ridge thrust belt: Balanced structural sections, Pennsylvania to Alabama: University of Tennessee Geological Sciences Studies in Geology 12, p. 40-53.

Zietz, Isidore, Gilbert, F.P., and Kirby, J.R., Jr., 1980, Aeromagnetic map of Delaware, Maryland, Pennsylvania, West Virginia, and parts of New Jersey and New York: U.S. Geological Survey Geophysical Investigations Map GP-927, 1 sheet, scale 1:1,000,000.

FOOTNOTES [ Top ]

¹The Bull Fork Formation was named by Peck (1966) in northeastern Kentucky. Gibbons and Weiss (1972) and Weiss and others (1972) have extended the Bull Fork Formation into southern Ohio.

²The Grant Lake Limestone was named by Peck (1966) in northeastern Kentucky. Gibbons and Weiss (1972), Weiss and others (1972), and Schumacher and others (1991) have extended the Grant Lake Limestone into southern Ohio.

³The Point Pleasant Formation as used in Ohio by Gibbons and Weiss (1972), Weiss and others (1972), Shrake and others (1990), and Schumacher and Carlton (1991) correlates with the Point Pleasant Tongue of the Clays Ferry Formation as used in Kentucky by Weir and others (1984). Bergstradom and Mitchell (1989) assign a Middle Ordovician age to the Point Pleasant Formation and the equivalent Utica Shale in southern and southwestern Ohio. However, as discussed by Pojeta (in Weir and others, 1984), the Point Pleasant Tongue of the Clays Ferry Formation also contains beds of Late Ordovician age. On the basis of these studies, we assign a Middle and Late Ordovician age to the Point Pleasant Formation.

⁴The Lexington Limestone is extended into the subsurface of southern Ohio by Stith (1986), Shrake and others (1990), and Schumacher and Carlton (1991). The Lexington Limestone in Ohio replaces the |P`Trenton and |P`Cynthiana beds identified on cross sections by Stith (1986). In southeastern Ohio and adjoining West Virginia, the Lexington Limestone is replaced by the Trenton Limestone and the lowermost part of the Reedsville Shale, units that are more commonly used in the central Appalachian area.

⁵The |ga marker of Stith (1979, 1986) that directly underlies the Lexington Limestone in southern Ohio is known in adjoining Kentucky as either the Mud Cave bed (Huff, 1983; Stith, 1986) or the Millbrig Bentonite Bed (Huff and Kolata, 1990).

⁶The |gb marker of Stith (1979, 1986), located in the uppermost part of the Black River Group approximately 20 ft (6 m) below the |ga marker, is known in adjoining Kentucky as the Pencil Cave bed (Huff, 1983; Stith, 1986) or the Deicke Bentonite Bed (Huff and Kolata, 1990).

⁷The Lower Silurian |P`Clinton sandstone and shale of Janssens (1977) and the |P`Clinton sands of Pepper and others (1953) in Ohio are extended into western West Virginia as the |P`Clinton sandstone of O'Brien (1970).

⁸The Reedsville Shale is extended into the subsurface of eastern Ohio and western West Virginia by Calvert (1964).

⁹The Drowning Creek Formation, consisting in ascending order of the Brassfield Member, undifferentiated rocks, and the Dayton Dolomite Member, was named by McDowell (1983) in northeastern Kentucky. McDowell (1983) extended the Brassfield Member of the Drowning Creek Formation into adjoining western West Virginia. In the western West Virginia part of section F-F`, we follow McDowell (1983) and use the name Brassfield Member of the Drowning Creek Formation. Moreover, although not extended into West Virginia by McDowell (1983), the unit he named the Dayton Dolomite Member of the Drowning Creek Formation in Kentucky also is applicable to the Silurian sequence in the westernmost West Virginia part of section F-F`.

¹⁰ We follow Cable and Beardsley (1984) and use the name Black River Group for the limestone sequence in western West Virginia between the Beekmantown Group and the Trenton Limestone. The Black River Group extends into Ohio (Stith, 1979), but the lowermost strata of the group in West Virginia are slightly older than the lowermost strata in Ohio.

¹¹The term Gatesburg Formation is used in the westernmost West Virginia part of section F-F` for dolomite and dolomitic sandstone between the Nolichucky Shale and the Beekmantown Group. The use of the Gatesburg Formation here follows the use of this term in section E-E` (Ryder, 1992a). In the Rome trough and Valley and Ridge parts of section F-F`, the name Copper Ridge Dolomite is used to accommodate terminology applied to the uppermost Cambrian sequence in West Virginia (Cable and Beardsley, 1984; Patchen and others, 1984; Donaldson and others, 1988) and southwestern Virginia (Butts, 1940; Rader, 1982). In this study the Copper Ridge Dolomite is subdivided into informal lower and upper sandstone members and a middle dolomite member. The upper sandstone member correlates with the upper sandy member of the Gatesburg Formation in westernmost, central, and northern West Virginia and the Rose Run Sandstone Member of the Knox Dolomite in Ohio. The upper sandy member of the Copper Ridge Dolomite and its correlative sandstone units, including the Rose Run Sandstone Member, have been considered to be Late Cambrian in age (Wilson, 1952; Ryder, 1992a). However, stratigraphic revision presented here in the section on Conodont Biostratigraphy and Age of the Copper Ridge and Beekmantown Dolomites suggests that these sandstone-bearing units in section F-F` are Late Cambrian or Early Ordovician(?) in age.

¹²The names Blackford Formation, Elway Limestone, Five Oaks Limestone, Peery Limestone, Benbolt Limestone, Wardell Formation, Witten Limestone, Moccasin Formation, and Eggleston Formation were originally applied to the Middle Ordovician limestone sequence in Virginia (Cooper and Prouty, 1943; Cooper, 1945, 1961). The terms have been extended into adjoining West Virginia by Cooper (1961, 1971) and Read (1980).

¹³In southwestern Virginia and adjoining West Virginia the name Martinsburg Formation is applied to the shale and limestone sequence of Middle and Late Ordovician age between the Eggleston and Juniata Formations (Butts, 1940; Cooper, 1945, 1961; McDowell and Schultz, 1990). The Martinsburg Formation as used here is equivalent to the Trenton Limestone and Reedsville Shale of western West Virginia.

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