POTENTIAL SEEN IN MIDDLE RUN BASINS OF WESTERN OHIO

Paul J. Wolfe, Benjamin H. Richard
Wright State University
Dayton

Paul E. Potter
University of Cincinnati
Cincinnati

Basins containing the Middle Run formation are widespread in western Ohio and are also present in southeastern Indiana and central Kentucky.

This is shown by 213 km of seismic lines now in the public domain (Fig. 1) and by 10 wells (Table 1) that penetrate the formation.

The most recent of these wells is the BP Chemical No. 4 well in Lima, Ohio, which drilled into the uppermost 46 m of the Middle Run.1

The BP well is significant for the following reason: it extends the Middle Run lithology about 100 km north of the original subsurface type section in Warren County2 and is closer to the Midcontinent rift system, which has been identified in the southern peninsula of Michigan.3

Armed with this knowledge, we have used all the available public seismic sections in western Ohio to develop a regional assessment of the sedimentary basins underlying its Phanerozoic section including some speculations about its petroleum potential.

Our seismic interpretation is supplemented by careful logging and petrologic study of the 582 m of Middle Run drilled in the Warren County well and by study of cuttings of all the other Middle Run wells and some additional ones.

Essential background references for our study include papers by Lucius and von Frese,4 Shirley,5 Shrake,6 Shrake et al.,7 Pratt et al.,89 and the broad regional review by Drahovzal et al.,10 which covers four states.

SEISMIC CHARACTERISTICS

Our seismic identification of the Middle Run is based on its seismic character in its type section as seen in Ohio Geological Survey Drill Hole 262726 Pin northern Warren County (Table 1), where 582 m of it was penetrated and a seismic line was shot across the well (Fig. 2, Table 2).

Here the Middle Run has a relatively homogeneous, low amplitude signal with only a few fairly continuous reflectors. This response results from the great dominance of uniform sandstone that typifies the Middle Run in its type section and seems to prevail throughout much of western Ohio.

We have picked the base of the Middle Run at the first appearance of strong high amplitude reflections, which appear to be common in much of the eastern Midwest. When these reflectors are poorly defined we could not positively identify the base of the Middle Run.

Tables 1, 2, and 3 summarize the characteristics of all these lines, and Figs. 2, 3, and 4 show their interpreted sections, all at the same proportions. Based on the above interpretation strategy, five broad conclusions were obtained.

1. The thickest Middle Run sections are all in structural basins-full or half grabens or synclines.

2. The thinnest Middle Run sections occur as remnant sheets.

3. The absence of the Middle Run in some seismic sections suggests a long period of deep erosion prior to deposition of the Middle Cambrian Mount Simon sandstone.

4. In some sections there is a low angle unconformity between the Middle Run and the Mount Simon.

5. Much of the broad structure present in the isolated basins filled by the Middle Run is also present in the underlying layered sequence recently described by Pratt et al.9

6. One can see extensional faulting and clinoforms in the thick layered sequence below the Middle Run.

PETROLOGY, SOURCE

The Middle Run formation consists of more than 95% densely compacted grayish red sandstone with a few silty, brownish red shales or argillaceous siltstones. It has many thin, fining-upward fluvial cycles typically with a sharp base and a few scattered lags of pebbles.

Much of the sandstone is massive; the scattered clasts in the Middle Run are never abundant and never form true conglomerates. The pebbles are mostly volcanics and include basalt, devitrified acid glass and some lithified red shales, siltstones, and sandstones.

Poorly defined cross bedding, rarely abundant, typically passes upward to parallel lamination and/or small scale ripple lamination in siltstones. Minor small, irregularly calcite cemented masses, with an open framework of grains, suggest incipient caliche and thus a dry climate.

As seen in thin section, the sandstone of the Middle Run consists mostly of a tightly compacted, moderately to well sorted framework of subangular grains with only a few percent detrital matrix. Some early calcite is present but is highly variable ranging from complete absence to more than 30% in a few thin sections.

Porosity is almost totally absent where we have observed it in cuttings and cores, and hence we hold little hope that the Middle Run sandstone itself could ever be a petroleum reservoir or a site for liquid waste injection.

Quartz is a major framework grain of the sand fraction, is mostly angular to subangular, and is chiefly monocrystalline. Total feldspar has a narrow range of abundance, usually 12-20%, and is mostly potash feldspar.

Rock fragments are always abundant and typically form 30-40% of all framework grains, although a few samples consist of almost 60%. The dominant rock fragments are volcanics followed by metamorphic grains, although sandstones, siltstones, and plutonic grains are present as are argillaceous grains. The volcanic rock fragments include many dark, dense, fine grained volcanics with a few stray laths of plagioclase.

Also present are acid (potash-rich) aphanitic chert-like volcanics of altered glass and similarly textured, but non potash-rich, siliceous grains as well as typical volcanic (andesitic?) grains with a well defined fabric of plagioclase laths. The most abundant of these are fine grained siliceous volcanics that are potash rich. Cherts, opaques, and heavy minerals rarely exceed 1%.

The dominant source of much of the Middle Run appears to have been the Eastern Granite-Rhyolite province to the west due to the predominance of potash feldspar and volcanic debris although some sand sized metamorphic rock fragments are also present indicating a lesser derivation from the east.

PROVINCIAL RELATIONSHIPS

We believe that the Middle Run formation is younger than either the Eastern Granite-Rhyolite or the Grenville province for two major reasons.

First, both the Cocorp East and the Consortium-Wright State lines show seismic contrast below the Middle Run-at the western end of both is the distinctive high amplitude layering characteristic of what has been considered to be part of a large Proterozoic basin,9 whereas the eastern ends of these lines have weaker, discontinuous reflections broadly similar to those of the Selma line, which is well within the Grenville province.

Second, virtually all the pebbles and many of its sand-sized rock fragments in the Middle Run have a rhyolitic-granitic origin indicating that the Eastern Granite-Rhyolite province was a major and probably the dominant source.

Our seismic study also suggests two other major conclusions. First, the Middle Run is everywhere separated from the underlying, thick layered sequence by an unconformity and, in addition, the structure of the Middle Run commonly mimics-but always with lesser intensity-the structure of the layered sequence beneath it. Additionally, in a few sections some faulting cuts both units. Taken together, we draw the following principal conclusions form these observations:

1. The Middle Run was deposited after both the Grenville and Eastern Granite-Rhyolite provinces had long ceased to form and possibly might be Eocambrian in age.

   Regionally we note that other red sandstones in eastern North America have been tentatively assigned Eocambrian ages. Rankin11 12 13 and Schwab14 discuss a late Precambrian opening and closing of the proto-Atlantic Iapetus Ocean with post-Grenvillian immature red sandstones filling rift or riftlike basins.

   See Schwab (Table 1) for a late-Precambrian age for the Ocoee Supergroup in Georgia and South and North Carolina, the Grandfather Mountain formation in North Carolina and Tennessee, and the Mount Rogers formation in Virginia, as well as the Catocin formation to the north.

   In addition, Milkereit et al.15 recognized sediments deposited in post-Grenvillian riftlike basins in peninsular Ontario. Dalziel16 has also written about a late-Precambrian separation of North from South America.

   We recognize, however, two arguments opposing this interpretation: (1) the lithologic similarity between the Middle Run and Keweenawan sandstones and (2) the thick section of theoletitic basalt that overlies the Middle Run in the Texaco No. 1 Sherrer well southwest of Lexington, Ky. (Fig. 5).

   But we point out that similar lithology does not necessarily equate to similarity of age. In addition, Hinze et al.17 show the Midcontinent rift crossing southern Michigan into Canada at Detroit.

2. The Middle Run seems to have been originally a widespread sheet locally filling structural lows and its paleoslope was largely to the southeast toward the then margin of the Laurentian paleocontinent.16 The dominance of volcanic debris suggests a paleoslope to the southeast, but only oriented downhole paleocurrent data can provide a positive answer.

3. After Middle Run deposition, there was some renewed tectonic activity that produced the structural basins where the Middle Run is thickest. Prior to deposition of the Upper Cambrian Mount Simon sandstone, however, erosion removed much of this wide spread sheet so that the Middle Run is now only preserved in structural basins or as isolated remnants (Fig. 6), which today occur in a north-south zone that extends from southwest of Lexington, Ky., to at least as far north as Putnam County, Ohio.

UNRESOLVED PROBLEMS

We also recognize important, unresolved problems that deserve more attention.

Foremost is firm knowledge of the age of the Middle Run formation without which no precise late Proterozoic paleographic and tectonic history of the eastern Midcontinent is possible.

Perhaps second in importance is the nature and composition of the layered sequence below it. The gravity and magnetic signature of most of the shaded area (scattered structural basins and remnants) of Fig. 7 unlike the Midcontinent rift, does not correlate well with basins of the Middle Run.

The larger issue here-and one already identified by Pratt et al.9-is the relative weight to be assigned to pre-Mount Simon lithologies found in scattered deep wells drilled on structural highs vs. the combined systematic evidence of gravity and magnetic studies supplemented by some seismic lines.

This question especially deserves thoughtful consideration, because most of the penetrations of the Precambrian extend only a few rather than many meters into it unlike wells 1, 3, 4, 5, 7, and 8 of Table 1. The three wells along the Cocorp line described by Drahovzal et al.10 (Fig. 5 and Table 1) illustrate well the difficulties of harmonizing seismic facies with a few meters of cuttings 3-10 km from the line, especially when some volcanics may be interlayered with the Middle Run.

But by far the most intriguing question-and one with the most relevance for petroleum exploration in the eastern Midcontinent-is the pre-Mount Simon section encountered in the Friend 1 Mattinson well (Permit D-2) drilled in 1926 southeast of Springfield, Ohio, in Madison township of Clark County.

Isabel Wasson, wife of Theron Wasson, founder of Pure Oil Co. reported on this well in 1932.18 The following description, with depths in meters and description and geologic age, is summarized from Norris et al. (his well 1239, p. 82).19

0-36 in, glacial drift of Pleistocene age; 36-111 in, limestone and shale of Silurian age; 111-379 in, shale of Ordovician age.

379-565 in, limestone of Ordovician age; 565-809 in, dolomite of Lower Ordovician age; uniform, finely crystalline, white dolomite, often mistaken for sandstone.

809-1,042 in, mostly sandstone of Upper Cambrian age; 1,042-1,170 in, gray dolomite, with some sandstone and arkose, of Lower Cambrian or Precambrian age; 1,170-1,416 in, black carbonaceous limestone, probably of Precambrian age.

Norris et al.19 also reported a show of gas at 975 in and of oil at 544 in and in the black limestone at 1,329 in.

Drahovzal et al.10 (Table 2, Well 23) have suggested that the black limestone described by Wasson18 is altered basalt and rhyolite. However, a thin section of a composite sample of cuttings from the interval with the oil show confirms it to be a micritic and finely holo-crystalline limestone with scattered small masses of pyrite and small disperse organic blebs.

Is this limestone a facies of the Middle Run or does it have a totally different age be it Grenville or Lower or Middle Cambrian? Lockett20 (Fig. 2) perceptively suggested that this black limestone section was part of a larger Precambrian basin that opened to the south. Comparison of the Consortium-Wright State and Selma lines lends some support to the possibility that both seismic lines belong to the same basin.

Whatever the age and correlation of the pre-Mount Simon section in the Friend 1 Mattison well, it is without doubt one of the most provocative and puzzling-and certainly one of the most significant for petroleum-in the eastern Midcontinent. Thus it clearly deserves several more seismic lines and a twinned well.

ACKNOWLEDGMENTS

This article would not have been possible without data supplied by a number of organizations. The well data from Warren County, Ohio, came from Ohio Department of Natural Resources, Division of Geological Survey. The Warren County seismic line was acquired by a consortium that included Ohio Department of Natural Resources, Stocker & Sitler Inc., University of Cincinnati, and Wright State University. This consortium was monetarily supported by Cincinnati Gas & Electric, Dayton Power & Light, Columbia Natural Resources, Ohio Oil & Gas Association, Paragon Geophysical, and Wright State University. The data were processed at no charge by Hosking Geophysical, Strata Search, Stroder & Unruh Geophysical, Unocal, and Woods Geophysical. The Wright State University seismic lines were supported by grants from Amoco, Conoco, British Petroleum, Unocal, and ARCO oil companies, and some of the shot hole drilling was done by Duncan Exploration. These lines were processed by Lauren and Woods Geophysical companies. Grants from the above oil companies paid for the Cocorp tapes that were reprocessed by Lauren Geophysical.

Armco Steel and BP Petroleum provided the seismic lines in Middletown and Lima. These lines are quality control lines in support of their disposal wells in the Mount Simon sandstone.

Finally we thank Eileen Porter of Wright State University and Charon Kirkland of University of Cincinnati who patiently worked with us preparing this manuscript.

REFERENCES

1. Keckler, K.P., Project Merjer, The UIC no migration demonstration: BP Chemicals, Lima, Ohio, Vol. 1-11, 1991, various paging.

2. Shrake, Douglas L., Wolfe, Paul J., Richard, B.H., Swinford, E., Wickstrom, L.H., Potter, P.E., and Sitler, G.W., 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 core site, Ohio Department of Natural Resources, Division of Geological Survey Information Circular 56, 1990, 11 P.

3. Wollensak, M.S., ed., Upper Keeweenawan rift-fill sequence, Midcontinent rift system, Michigan, Michigan Basin Geological Society 1988 Fall Field Trip Guidebook, Michigan State University, East Lansing, 1988, 130 P.

4. Lucius, J.E., and von Frese, R.R.B., Aeromagnetic and gravity anomaly constraints on the crustal geology of Ohio, Geological Society of America Bull., Vol. 100, 1988, pp. 104-116.

5. Shirley, Kathy, Ohio buried basin challenges theory, AAPG Explorer, March 1990, pp. 8-11.

6. Shrake, D.L., The Middle Run Formation: A subsurface stratigraphic unit in southwestern Ohio, Ohio Jour. Sci., Vol. 91, 1991, pp. 49-55.

7. Shrake, Douglas L., Carlton, R.W., Wickstrom, L.H., Potter, P.E., Richard, B.H., Wolfe, P.J., and Sitler, G.W., A pre-Mount Simon basin under the Cincinnati arch, Geology, Vol. 19, 1991, pp. 139-142.

8. Pratt, T., Culotta, R., Hauser, E., Nelson, D., Brown, L., Kaufman, S., Oliver, J., and Hinze, W., Major Proterozoic basement features of the eastern Midcontinent of North America revealed by recent Cocorp profiling, Geology, Vol. 17, 1989, pp. 505-509.

9. Pratt, T.L., Hauser, E.C., and Nelson, K.D., Widespread buried Precambrian layered sequences in the U.S. Midcontinent, Evidence for large Proterozoic depositional basins, AAPG Bull., Vol. 76, 1992, pp. 1,384-1,401.

10. Drahovzal, J.A., Harris, D.C., Wickstrom, L.H., WaLker, Dan, Baranoski, M.T., Keith, Brian, and Furer, L.C., The last continent rift basin: A new discovery, Kentucky Geological Survey, Series Xi, Special Publication 18 (Cincinnati Arch Consortium), 1992, 25 p.

11. Rankin, D.W., Guide to the Geology of the Mt. Rogers Area, Virginia, North Carolina, and Tennessee, Carolina Geological Survey, 1967, 48 p.

12. Rankin, D.W., The continental margin of eastern North America in the southern Appalachians-the opening and closing of the proto-Atlantic oceans, American Journal of Science, Vol. 275A, 1975, pp. 298-336.

13. Rankin, D.W., Appalachian salients and recesses: Late Precambrian continental breakup and the opening of the Iapetus Ocean, Journal of Geophysical Research, Vol. 81, 1976, pp. 4,605-5,019

14. Schwab, F.L., Upper Precambrian-Lower Paleozoic clastic sequences, Blue Ridge and adjacent areas, Virginia and North Carolina, Initial rifting and continental margin development, Appalachian Orogen, in Textoris, D.A., ed., SEPM Field Guidebooks, southeastern U.S., 3rd annual midyear meeting, 1986, pp. 1-42.

15. Milkereit, B., Forsyth, D.A., Green, A.G., Davidson, A., Hanmer, S., Hutchinson, D.R., Hinze, W.J., and Mereu, R.F., Seismic images of a Grenvillian terrane boundary, Geology, Vol. 20, 1992, pp. 1,027-30.

16. Dalziel, W.D., Pacific margins of Laurentia and East Antarctica Australia as a conjugate rift pair: Evidence and implications for an Eocambrian supercontinent, Geology, Vol. 19,1991, pp. 598-601.

17. Hinze, W.J., Allen, D.J., Fox, A.J., Sunwood, D., Woelk, T. and Green, A.G., Geophysical investigations and crystal structure of the North American Midcontinent rift system, Tectono-physics, Vol. 213, 1992, pp. 17-32.

18. Wasson, I.B., Sub-Trenton formations in Ohio, Journal of Geology, Vol. 40, 1932, pp. 673-687.

19. Norris, S.E., Cron, W.P., Goldthwait, R.P., and Sanderson, E.E., The water resources of Clark County, Ohio, Ohio Division of Water, Bull. 22, 1952, 82 p.

20. Lockett, J.R., Development of structures in basin areas of northeastern U.S., AAPG Bull., Vol. 31, 1947, pp. 429-446.

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