Hostname: page-component-76fb5796d-2lccl Total loading time: 0 Render date: 2024-04-30T03:23:57.329Z Has data issue: false hasContentIssue false

Petrology of the Desmoinesian Excello Black Shale of the Midcontinent Region of the United States

Published online by Cambridge University Press:  02 April 2024

Omer Isik Ece*
Affiliation:
Department of Geosciences, University of Tulsa, Tulsa, Oklahoma 74104
*
1Present address: Mineralogy and Petrography Department, Faculty of Mines, Istanbul Technical University, Tesvikiye, Istanbul, Turkey.

Abstract

The Excello Shale is one of the best exposed and most laterally continuous of the Pennsylvanian cyclothemic black shales in the midcontinent region of the United States. Its petrology and paleoenvi-ronmental significance were studied to understand the nature of cyclic black shales in general and how they relate to the habitat of hydrocarbon source beds. The Excello is thinly laminated, fissile where weathered, and rich in organic matter and phosphate nodules; it is 90–120 cm thick. Its thin laminations, fine particle size, and high total organic carbon (TOC) content suggest that it was deposited in a quiet water environment of an epeiric sea having anaerobic bottom water. The Excello Shale consists of two lithofacies: non-bioturbated black shale and bioturbated yellow-brown shale. Petrographic studies show that the black shale contains wavy to straight laminations and that the yellow-brown shale contains discontinuous and random laminae and mottled stratification. The close association of organic matter and phosphate-controlled nodule morphology (spherical, elongated, bladed, and platy) appear to be related to progressive decreases in nutrient supply of the sea water from the ancient ocean (Panthalassa).

Clay-mineral assemblages consist mainly of detrital illite, kaolinite, chlorite, and illite/smectite (I/S). Grain size and amount of these clays increase and TOC decreases shoreward towards the probable source areas of the clay minerals in the northern Ouachita region and northern Iowa. Quartz, carbonate-fluor-apatite, carbonate fossil fragments, and minor feldspar and pyrite are the principal minerals in the Excello Shale. Minor amounts of fine-silt-size carbonate minerals are present in some samples. Limestone concretions, 90–150 cm in diameter and 30 cm thick, were found at only one locality in Missouri where the Excello is a maximum of about 3 m thick. Fissility increases with weathering along the bedding plane, and laminae are separated by a limonite film. Four petrographically distinct microfabric variations of the Excello Shale appear to be related to the TOC content and bioturbation. Textural and structural properties of the shale are more developed with increasing organic matter content.

Type
Research Article
Copyright
Copyright © 1987, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baturin, G. N., 1972 Phosphorus in interstitial waters of sediments of the southeastern Atlantic Oceanology 12 849855.Google Scholar
Bennison, A. P. et al. (1972) Tulsa’s physical environments: Tulsa Geological Society Digest, 37, 489 pp.Google Scholar
Berner, R. A., 1969 Migration of iron and sulfur within anaerobic sediments during early diagenesis Amer. J. Sci. 267 1942.CrossRefGoogle Scholar
Berner, R. A., 1982 Burial of organic carbon and pyrite sulfur in the modern ocean: Its geochemical and environ-mental significance Amer. J. Sci. 282 451473.CrossRefGoogle Scholar
Branson, C. C., 1954 Field conference on Desmoinesian rocks of northeastern Oklahoma Guidebook II, Oklahoma Geol. Sum. .Google Scholar
Branson, C. C., Huffman, G. G. and Strong, D. M. (1965) Geology, oil and gas resources of Craig County, Oklahoma: Oklahoma Geol. Surv. Bull. 99, 109 pp.Google Scholar
Brewer, R., 1976 Fabric and Mineral Analysis of Soils Huntington, New York Krieger Publ. Co..Google Scholar
Brindley, G. W., 1981 X-ray identification of clay minerals Short Course in Clays and the Resource Geologist 7 138.Google Scholar
Brongersma-Sanders, M., 1971 Origin of major cyclicity of evaporites and bituminous rocks: An actualistic model Marine Geol. 11 123144.CrossRefGoogle Scholar
Brown, G., ed. (1961) The X-ray Identification and Crystal Structures of Clay Minerals: Mineralogical Society, London, 544 pp.Google Scholar
Burnett, W. C., 1977 Geochemistry and origin of phosphorite deposits from off Peru and Chile Geol. Soc. Amer. Bull. 88 813823.2.0.CO;2>CrossRefGoogle Scholar
Cassidy, M. M., 1968 Excello Shale, northeastern Oklahoma: Clue to locating buried reefs Amer. Assoc. Petrol. Geol. Bull. 52 295312.Google Scholar
Claypool, G. E., Kaplan, I. R. and Kaplan, I. R., 1974 The origin and distribution of methane in marine sediments Natural Gases in Marine Sediments New York Plenum Press 99140.CrossRefGoogle Scholar
Cronoble, W. R. and Mankin, C. J. (1965) Petrology of the Hogshooter Formation: Oklahoma Geol. Surv. Bull. 107, 148 pp.Google Scholar
Drever, J. I., 1984 The Geochemistry of Natural Waters New Jersey Prentice-Hall.Google Scholar
Dunbar, R. B. and Berger, W. H., 1981 Fecal pellet flux to modern bottom sediment of the Santa Barbara basin (California) based on sediment trapping Geol. Soc. Amer. Bull. 92 212218.2.0.CO;2>CrossRefGoogle Scholar
Flawn, P. T., 1961 Metamorphism in the Ouachita belt The Ouachita System: Texas Bur. Econ. Geol. Publ. 6120 122124.Google Scholar
Folk, R. L., 1974 Petrology of Sedimentary Rocks Austin, Texas Hemphill Publishing Co..Google Scholar
Gibbs, R. J., 1965 Error due to segregation in quantitative clay mineral X-ray diffraction mounting techniques Amer. Mineral. 50 741751.Google Scholar
Gieskes, J. M., Elderfield, H., Lawrence, J. R., Johnson, J., Meyers, B. and Campbell, A., 1982 Geochemistry of interstitial waters and sediments, leg 64. Gulf of California Initial Reports of the Deep Sea Drilling Project Washington, D. C. U.S. Government Printing Office 675694.Google Scholar
Heckel, P. H., 1977 Origin of phosphatic black shale facies in Pennsylvanian cyclothems of midcontinent North America Amer. Assoc. Petrol. Geol. Bull. 61 10451068.Google Scholar
Heckel, P. H., 1986 Sealevel curve for Pennsylvanian eustatic marine transgressive-regressive depositional cycles along midcontinent outcrop belt, North America Geology 14 330334.2.0.CO;2>CrossRefGoogle Scholar
Hennessy, J. and Knauth, L. P., 1985 Isotopic variations in dolomite concretions from the Monterey Formation, California J. Sediment. Petrol. 55 120130.Google Scholar
Kidder, D. L., 1985 Petrology and origin of phosphate nodules from the midcontinent Pennsylvanian epicontinental sea J. Sediment. Petrol. 55 809816.Google Scholar
Lewan, M. D., 1978 Laboratory classification of very fine grained sedimentary rocks Geology 6 745748.2.0.CO;2>CrossRefGoogle Scholar
Manheim, F., Rowe, G. T. and Jipa, D., 1975 Marine phosphorite formation off Peru J. Sediment. Petrol. 45 243251.Google Scholar
Miyashiro, A., 1978 Metamorphism and Metamorphic Belts London George Allen Unwin.Google Scholar
Ostrom, M. E., 1961 Separation of clay minerals from car-bonate rocks by using acid J. Sediment. Petrol. 31 123129.Google Scholar
Pettijohn, F. J., 1975 Sedimentary Rocks New York Harper & Row.Google Scholar
Porter, K. G. and Robbins, E. I., 1981 Zooplankton fecal pellets link fossil fuel and phosphate deposits Science 212 931933.CrossRefGoogle ScholarPubMed
Potter, P. E., Maynard, J. B. and Pryor, W. A., 1980 Sedi-mentology of Shale New York Springer-Verlag.CrossRefGoogle Scholar
Reimers, C. E., 1982 Organic matter in anoxic sediments off central Peru: Relations of porosity, microbial decom-position and deformation properties Marine Geol. 46 175197.CrossRefGoogle Scholar
Raiswell, R., 1971 The growth of Cambrian and Liassic concretions Sedimentology 17 147171.CrossRefGoogle Scholar
Schultz, L. G., 1964 Quantitative interpretation of min-eralogical composition from X-ray and chemical data for the Pierre Shale U.S. Geol. Surv. Prof. Pap. 131.CrossRefGoogle Scholar
Suess, E., 1981 Phosphate regeneration from sediments of the Peru continental margin by dissolution of fish debris Geochim. Cosmochim. Acta 45 577588.CrossRefGoogle Scholar
Williams, L. A. and Reimers, C. E., 1983 Role of bacterial mats in oxygen-deficient marine basins and coastal up-welling regimes: Preliminary report Geology 11 267270.2.0.CO;2>CrossRefGoogle Scholar
Yoder, H. S. and Eugster, H. P., 1955 Synthetic and natural muscovites Geochim. Cosmochim. Acta 8 225280.CrossRefGoogle Scholar