Abstract
Progressive burial diagenesis of Hunton Group (Upper Ordovician to Lower Devonian) rocks of the deep Anadarko Basin of Oklahoma and the Texas Panhandle is evident from petrographic and geochemical study of cores and cuttings from more than 25 boreholes up to 30,000 ft deep. Limestone of the Hunton Group, which originated as shallow shelf carbonates, has been replaced, chiefly below present depths of about 10,000 ft, by dolomite that is commonly ferroan and is associated with shale. This diagenetic dolomite is inferred to have formed under deep-burial conditions.
The dolomite occurs as finely disseminated, 10μm and larger rhombic crystals, and is most abundant near the base of the Hunton Group, particularly where an oolite unit (the Keel Formation) overlies the thick marine Sylvan Shale that is inferred to be the chief source of Fe2+ and Mg2+ ions. Ferroan dolomite also occurs where clay minerals are abundant in the Middle Hunton Group. In shallow wells, dolomite crystals are euhedral. Below 10,000 ft(3.0 km), where dolomitization of the oolite has been more complete, hypidiotopic and xenotopic textures result. Hydrocarbon-associated fluids are inferred to have dissolved the calcite that was not replaced, and to have created intercrystalline and moldic porosity.
X-ray diffraction verifies a trend of higher dolomite concentrations with increasing depth in the same oolite horizon. For example, oolite samples from outcrop lack dolomite and are 100% CaCO3; cores from 9,200 ft (2.8 km) are about 25% dolomite; and cores from 15,000 ft (4.6 km) and below are more than 85% dolomite. Radioisotope-induced x-ray fluorescence shows that dolomites below 10,000 ft(3.0 km) are iron-enriched relative to both non-dolomitized oolite and dolomites of surface origin. Where the Hunton Group and the Sylvan Shale are buried below 10,000 ft(3.0 km), well logs show high densities in the lowermost Hunton (above the Sylvan Shale) which can be interpreted as the occurrence of Fe2+- rich dolomite. Stable isotope ratios suggest a higher temperature of origin for burial dolomites than for dolomites of surface origin. Formation waters recovered from within the shale and carbonate are greatly depleted in Mg2+ ions compared to normal marine waters.
General restriction of this shale-associated ferroan dolomite to strate that are currently buried below 10,000 ft (3.0 km) in the Anadarko basin supports other lines of evidence for the belief that previously deeply buried strate can be recognized even if the strata have been subsequently uplifted. The transformation of smectite to illite in the Sylvan Shale (conformably underlying the oolite) is suggested as a possible source of Mg2+ and Fe2+. Smectite/illite ratio decreases with increasing depth in the Sylvan Shale. Furthermore, Sylvan Shale below 10,000 ft(3.0 km) is depleted in iron by 70% relative to Sylvan Shale less than 10,000 ft(3.0 km) deep, suggesting that under deep conditions shales have given up their iron (and magnesium), presumably to the overlying carbonates.
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References
Al-Shaieb, Zuhair andShelton, J. W., 1978, Secondary ferroan dolomite rhombs in oil reservoirs, Chadra Sands, Giaolo Field, Libya: American Association of Petroleum Geologists Bulletin, Geologic Note, v. 62, p. 463–468.
Amsden, T. W., 1960, Hunton stratigraphy, pt. 6 of Stratigraphy and paleontology of the Hunton Group in the Arbuckle Mountains region: Oklahoma Geological Survey Bulletin 84, 311 p.
Amsden, T. W., 1975, Hunton Group (Late Ordovician, Silurian, and Early Devonian) in the Anadarko Basin of Oklahoma: Oklahoma Geological Survey Bulletin 121, 214 p.
Amsden, T. W., 1980, Hunton Group (Late Ordovician, Silurian, and Early Devonian) in the Arkoma Basin of Oklahoma: Oklahoma Geological Survey Bulletin 129, 136 p.
Amsden, T. W., 1983, Oolitic strata of the Keel Formation and Edgewood Group (late Ordovician and early Silurian), Texas Panhandle to the Mississippi Valley: Geological Society of America, Abstracts with Programs, v. 15, p. 222–223.
Amsden, T. W., and Sweet, W. C., 1983, Upper Bromide Formation and Viola Group (Middle and Upper Ordovician) in eastern Oklahoma: Oklahoma Geological Survey Bulletin 132, 76 p.
Aronson, J. L. andHower, John, 1976, Mechanism of burial metamorphism of argillaceous sediment: II. Radiogenic argon evidence: Geologic Society America, Bull., v. 87, p. 738–744.
Arthur, M. A.; Kaplan, I. R.; Veizer, Jan: and Land, L. S., 1983, Stable Isotopes in Sedimentary Geology. Tulsa Oklahoma, Society of Economic Paleontologists and Mineralogiest, Short Course No. 10 [held in Dallas Texas].
Asquith, G. B. and Gibson, C. R., 1982, Basic well log analysis for geologists: American Association Petroleum Geologists, Methods in Exploration, 216 p.
Boles, J. R., 1978, Active ankerite cementation in the subsurface Eocene of southwest Texas: Contributions to Mineralogy and Petrology, v. 68, p. 13–22.
Borak, Barry, andFriedman, G. M., 1981, Textures of sandstones and carbonate rocks in the world’s deepest wells: Anadarko Basin, Oklahoma: Sedimentary Geology, v. 29, p. 133–151.
Borak, Barry, andFriedman, G. M., 1982, Simpson (Ordovician) Sandstone and Hunton (Late Ordoivician to Early Devonian) Carbonate textures from deep parts of the Anadarko Basin: Shale Shaker, v. 32, no. 6, p. 1–8.
Dunoyer de Segonzac, G., 1970, The transformation of clay minerals during diagenesis and low-grade metamorphism-A review: Sedimentology, v. 15, p. 281–346.
Foscolos, A. E. and Powell, T. G., 1979, Mineralogical and geochemical transformation of clays during burial diagnesis (catagenesis): relation to oil generation, p. 261–270,in: Mortland, M. M. and Farmer, V. C., eds., Proc. 1978 International Clay Conference, Great Britain.
Friedman, G. M., Cataffe, Joseph, and Borak, Barry, 1983, Deep-burial diagenesis of the Hunton (Late Ordovician to Early Devonian) carbonates in the Anadarko Basin, p. 183–199in: Hyne, Norman, ed., Tulsa Geologic Society, Special Publication.
Friedman, G. M., Reeckmann, S. A., andBorak, Barry, 1981, Carbonate deformation mechanisms in the world’s deepest wells (9 km): Tectonophysics, v. 74, p. 715–719.
Friedman, G. M. andSanders, J. E., 1967, Origin and occurrence of dolostones, p. 267–378in: Chilingar, G. V., Bissel, H. J., and Fairbridge, R. W., eds., Carbonate rocks, origin, occurrence and classification: Amsterdam, Elsevier Publishing Company, 471 p.
Friedman, G. M. andSternbach, C. A., 1982, Identification of carbonates, gypsum, and anhydrite by staining: American Geologic Institute, Data Sheet 52, p. 52.1 to 52.2.
Friedman, G. M., Sternbach, C. A., and Cataffe, Joseph, 1982, Diagenetic textures in carbonate rocks buried at depths of −20,000 feet in the Anadarko, Delaware and Gulf Coast Basins: International Association Sedimentologists, 11th International Congress, Abstracts with Programs, p.
Gavish, Eliezer andFriedman, G. M., 1973, Quantitative analysis of calcite and Mg-calcite by x-ray diffraction: effect of grinding on peak height and peak area: Sedimentology, v. 20, p. 437–444.
Gregg, J. M., 1982, The origin of xenotopic dolomite texture: unpubl. Ph.D. thesis, Michigan State University, 151 p.
Gregg, J. M. andSibley, D. F., 1984, Epigenetic dolomitization and the origin of xenotopic dolomite texture: Journal of Sedimentary Petrology, v. 54, p. 908–931.
Hower, John;Eslinger, E. V.;Hower, M. E.; andPerry, E. A., 1976, Mechanism of burial metamorphism of argillaceous sediment, I. Mineralogical and chemical evidence: Geologic Society America, Bull., v. 87, p. 725–737.
Hower, John;Altaner, S. A.;Aronson, J. L. andWhitney, C. G., 1982, Kinetics and composition controls of the smectite to illite transformation: Geologic Society America, Abstracts with Programs, v. 14, no. 7, p. 519.
Jemison, R. M., Jr., 1979, Geology and development of Mills Ranch Complex- World’s deepest field: American Association Petroleum Geologists, Bull., v. 63, p. 804–809.
Johnson, K. S., 1979, Generalized cross section in Oklahoma: Oklahoma Geological Survey, Educational Publication 1, p. 1–8.
Kahle, C. F., 1965, Possible roles of clay minerals in the formation of dolomite: Journal Sedimentary Petrology, v. 35, p. 448–453.
Land, L. S., 1982, Dolomitization. Tulsa, Oklahoma, American Association of Petroleum Geologiest: Education Course Note Series #24, 20 p.
Mattes, B. W. and Mountjoy, E. W., 1980, Burial dolomitization of the Upper Devonian Miette buildup, Jasper National Park, Alberta, p. 259–297,in: Zenger, D. H., Dunham, J. B., and Ethington, R. L., eds., Concepts and models of dolomitization: Society of Economic Paleontologists and Mineralogists, Special Publication 28.
McHargue, T. R. andPrice, R. C., 1982, Dolomite from clay in argillaceous or shale-associated marine carbonates: Journal Sedimentary Petrology, v. 52, p. 873–886.
Pirsson, S. J., 1977, Geologic Well Log Analysis. Houston, Gulf Publishing Co., 2nd ed., 377 p.
Potter, P. E.;Maynard, J. B.; andPryor, W. A., 1980, Sedimentology of Shale. New York, Springer-Verlag, 306 p.
Sheppard, S. M. F., andSchwarcz, H. P., 1970, Fractionation of carbon and oxygen isotopes and magnesium between metamorphic calcite and dolomite: Contributions Mineralogy and Petrology, v. 26, p. 161–198.
Siever, Raymond, 1983, Burial history and diagenetic reaction kinetics: American Association of Petroleum Geologists, Bull., v. 67, p. 684–691.
Sternbach, C. A. and Friedman, G. M., 1983, Deep-burial diagenesis and dolomitization of Hunton Group carbonate rocks (Late Ordovician to Early Devonian) in the deep Anadarko Basin: Geologic Society America, Abstracts with Programs, v. 16, p. 696.
Sternbach, C. A. and Friedman, G. M., 1984, Ferroan carbonates formed at depth require porosity well-log corrections: Hunton Group, deep Anadarko Basin (upper Ordovician to lower Devonian of Oklahoma and Texas): West Texas Geological Society Guidebook, Transactions Southwest Section of American Association of Petroleum Geologists, p. 167–173.
Taylor, T. R., 1982, Petrographic and geochemical characteristics of dolomite types and the origin of ferroan dolomite in the Trenton Formation, Michigan Basin: unpubl. Ph.D. Thesis, Michigan State University, 75 p.
Tenant, C. B. andBerger, R. W., 1957, X-ray determination of dolomite-calcite ratio of a carbonate rock: American Mineralogist, v. 42, p. 28–29.
Zenger, D. H.; Dunham, J. B.; and Ethington, R. L., eds., 1980, Concepts and models of dolomitization: Society of Economic Paleontologists and Mineralogists, Special Publication #28, 320 p.
Zenger, D. H., 1983, Burial dolomitization in the Lost Burro Formation (Devonian), east-central California, and the significance of late diagenetic dolomitization: Geology, v. 11, no. 9, p. 519–522.
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Sternbach, C.A., Friedman, G.M. Dolomites formed under conditions of deep burial: Hunton Group carbonate rocks (Upper Ordovician to Lower Devonian) in the deep Anadarko Basin of Oklahoma and Texas. Carbonates Evaporites 1, 61–73 (1986). https://doi.org/10.1007/BF03174403
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DOI: https://doi.org/10.1007/BF03174403