Microfacies analysis and reservoir characters of eocene carbonates of Khair-i-Murat Range, Northern Potwar Deformed Zone (NPDZ), Sub-Himalayas, Pakistan
Paper Details
Microfacies analysis and reservoir characters of eocene carbonates of Khair-i-Murat Range, Northern Potwar Deformed Zone (NPDZ), Sub-Himalayas, Pakistan
Abstract
Khair-i-Murat Range is a fundamental part of Northern Potwar Deformed Zone (NPDZ), Sub-Himalayas. The geological investigations were carried out to understand the stratigraphy, sedimentology and tectonics of the area. The surface geology of the area is comprised of early Eocene to recent rock units. Eocene rocks namely; Margalla Hill Limestone, Chorgali Formation and Kuldana Formation are exposed along the Khair-i-Murat reverse fault. The petrographic study of Eocene carbonates of Chorgali Formation and Margalla Hill Limestone shows microfacies of various types. The Margalla Hill Limestone comprised of dolomitic, fossiliferous, nodular and fractured packstone to wackestone facies. The Chorgali Formation is dominated by sparsely fossiliferous, dolomitized and micritic limestone. The important microfacies of these carbonates are biomicrite, containing a variety of benthonic forams including different species of Assilina, Nummulities, Alveolina, Milliolids, Soritids and Textularia. The other common microfacies is dolomite. Cementation and supplementary alterations within the carbonate of these formations indicate that these are of early diagenetic origin. The major factor responsible for the development of secondary porosity and permeability in carbonate rocks was the fractures caused by intense structural deformation and development of thrust faults in Khair-i-Murat area. The presence of Eocene benthonic foraminiferal assemblages and dolomitization in the carbonate sequence of Margalla Hill Limestone and Chorgali Formation show the shallow marine, open shelf and intertidal to supratidal environments of deposition. The Early Eocene Margalla Hill Limestone, Chorgali Formation and Middle Eocene Kuldana Formation also indicate different transgression and regression periods of the Tethyan Ocean.
Brown S. 1943. Suggested use of the word microfacies, Suggested use of the word microfacies. Economic Geology 38, 325.
Choquette PW, Pray LC. 1970. Geological nomenclature and classification of porosity in sedimentary carbonates. American Association of Petroleum Geologists 54, 207-250.
Dunham RJ. 1962. Classification of carbonate rocks according to depositional texture. American Association of Petroleum Geologists 54, 1931-1932.
Folk RL. 1962. Spectral Subdivision of Limestone Types. American Association of Petroleum Geologists 1, 62-84.
Gansser A. 1964. Geology of the Himalayas. Willey, New York, p 289.
Jaswal TM. 1990. Structure and evolution of Dhurnal oil field, Northern Potwar Deformed Zone, Pakistan. Unpublished MS Thesis, Oregon State University Corvallis, p 63.
Kamran SM, Khan MS, Siddiqi MI, Munir MH. 2006. Micropaleontology and depositional environment of the Early Eocene Margalla Hill Limestone and Chorgali Formation of Khairi-Murat Range, Potwar Basin, Pakistan. Pakistan Journal of Hydrocarbon Research 16, 51-57.
Kazmi AH, Rana RA. 1982. Tectonic map of Pakistan. Geological Survey of Pakistan, Quetta, Pakistan.
Lillie RJ, Johnson GD, Yousuf M, Zaman ASH, Yeats RS. 1987. Structural development within the Himalayan Foreland fold-and-thrust belt of Pakistan. Canadian Society of Petroleum Geologists 12, 379-392.
Mc Dougall JW, Khan SH. 1990. Strike-slip faulting in a foreland fold-and-thrust belt: Kalabagh fault and western Salt Range, Pakistan. Tectonic 9, 1061-1076.
Molnar P, Tapponnier P. 1975. Cenozoic Tectonics of Asian effects of a continental collision science. Science 189, 419-426.
Mujtaba M. 1999. Depositional and diagenetic environments of Chorgali Formation. (Early Eocene) Salt Range Potwar Plateau, Pakistan, Unpublished Ph.D Thesis Institute of Geology, University of the Punjab, Lahore, Pakistan. p 187.
Roehl PO, Choquette PW. 1985. Carbonate Petroleum Reservoirs, New York, Springer-Verlag, p 1-15.
Kamran Mirza, Syed Muhammad Kamran, Muhammad Iqbal Siddiqi, Mian Sohail Akram, Muhammad Zeeshan, 2018. Microfacies analysis and reservoir characters of eocene carbonates of Khair-i-Murat Range, Northern Potwar Deformed Zone (NPDZ), Sub-Himalayas, Pakistan. J. Biodiv. Environ. Sci., 13(4), 88-100.
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