Micropaleontology of Lockhart Limestone (Paleocene), Nilawahan Gorge, Central Salt Range, Pakistan
Keywords:
Lockhart; Nilawahan Gorge; Foraminifera; PaleoceneAbstract
The present study deals with the micropaleontological investigation of the Lockhart Limestone of Paleocene age from the Nilawahan Gorge, Salt Range, Pakistan. 21m thick section of the Lockhart Limestone was measured and sampled in the Nilawahan Gorge at an interval of 1m. The limestone has a faulted lower contact with the Sardhai Formation (Lower Permian) and conformable upper contact with the Patala Formation (Upper Paleocene) and is predominantly nodular-bedded with interbeds of marls.
On the basis of detailed petrographic analysis, eight species of diagnostic benthic foraminifers belonging to genera Miscellanea, Operculina, Lockhartia, Assilina and Discocyclina, are recorded. The rocks are entirely of shallow marine in origin with biotic assemblages confirming Paleocene age of the Lockhart Limestone.
References
Afzal, J., Butt, A. A., 2000. Lower Tertiary planktonic biostratigraphy of the Salt Range, Northern Pakistan. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 12, 721-747.
Ashraf, M., Bhatti, M., 1991. Nannofossil biostratigraphy of the Patala and Nammal formations of Khairabad East, Western Salt Range, Pakistan. Hydrocarbon Development Institute of Pakistan (HDIP), unpublished report.
Davies, L. M., 1926. The Ranikot beds of Thal (Northwest Frontier Province of India). Geological Society of London, Quarterly Journal, 83, 281-282, Fig. 4, pl. 22.
Davies, L. M., 1930. The fossil fauna of the Samana Range and some neighbouring areas. Part 1, An introductory note. Memoirs Geological Survey of India, Paleontologica Indica, New Series, 15, 15.
Davies, L. M., 1932. The genera Dictyoconoides Nuttall, Lockhartia, and Rotalia Lamarck. Transactions of Royal Society of Edinburgh, 57, 407-408, p. 1-4.
Davies, L. M., Pinfold, E. S., 1937. The Eocene beds of the Punjab Salt Range. Memoirs of Geological Survey of India, Paleontologica Indica, New Series, 24, 1-79.
Fatmi, A. N., 1973. Lithostratigraphic units of the Kohat-Potwar Province, Indus basin Pakistan. Geological Survey of Pakistan Memoirs, 10, 66.
Gee, E. R., 1989. Overview of the geology and structure of the Salt Range, with observation on related areas of Northern Pakistan. In: Malinconico, L. L., Lillie, R.J. (Eds.), Tectonics of the Western Himalayas. Geological Society of America Special Paper, 232, 95-112.
Ghazi, S., Butt, A. A., Khan, K. A., Ashraf, M., 2004. Microfacies and foraminiferal assemblage of the Lower Eocene, Nammal Formation, Nilawahan Gorge, Central Salt Range, Pakistan. Geological Bulletin Punjab University, 39, 75-85.
Haque, A. F. M. M., 1956. Foraminifera of the Ranikot of the Laki of the Nammal Gorge, Salt Range, Pakistan. Geological Survey of Pakistan Memoirs, Palaeontologica Pakistanica, 1, 300.
Pfender, J., 1934. A propos du Siderolites Vidali Douville, Bulletin Geological Society of France, 4, 231-235, Figs. 1-4, Pl. 11, Figs. 67, pl. 13, Figs. 2-4.
Sameeni, S. J., 1997. Biostratigraphy of the Eocene succession of the Salt Range, Northern Pakistan, Unpublished PhD Thesis, Punjab University, 1-63.
Sameeni, S. J., 2009. The Salt Range; Pakistan’s unique field museum of geology and paleontology. Notebooks on Geology. (CG 2009- B03). Chapter 6, 65-73.
