Early molasse sediments (Murree Formation) in Pathan Algad, southern Kohat
Abstract
Of the southern most exposures of the Murree Formation in Kohat those of the Pathan Algad are considerably thick. These consist of interbedded maroon sandstone and red clay with subordinate conglomerate. The conglomerates within the formation are intrabasinal and lag in nature While conglomerate al base of the formation Consists of reworked limestone clasts of the underlying Kohat Formation. Two main sand-bodies, one SB1 starts at 13m level and is 21m thick and second SB2 at 52m level ranging 2-4m in thickness, were observed. These sand-bodies consist of main channel, point bar, and chute bar deposits. Interbedded sandstone and clay facies which overlie the composite sandstone facies represent levee or crevasse splay deposits. The red clay was deposited in flood plain areas out of suspension. As a whole the Murree Formation in this area displays typical meandering river deposits. Our analysis suggests that the Pathan Algad area lied the margin of the Murree river system where Only occasionally the main river flowed. Additionally, there may be a Considerable age difference between the exposures in Pathan Algad and those at Dhok Maiki, the strato type in Potwar area.
References
Ahmad, I., 1989. Sedimentology and Structure of Southern Kohat. Trans Indus ranges, Pakistan, Unpublished Ph.D. thesis, University of Cambridge, U.K.
Allen. J. R.L., 1984. Parallel lamination developed from upper stages plane beds: a model based on the larger coherent structures of the turbulent boundary layer sediments. Geol., 39, 227-242.
Arche, A., 1983. Coarse grained meander lobe deposits in the Jarama river, Madrid, Spain. Spec. Publ. Int. Ass. Sediment., 6, 313-332.
Bossart, P. & Ottiger, R., 1989. Rocks of the Murrce Formation: Indicators of a descending foreland basin of the late Paleocene to Middle Eocene age. Eclogae Geol. Helv., 82, 133-165.
Collinson, J. D., 1986. Alluvial sediments: In Sedimentary Environments and Facies (H. G. Reading. Ed.). Blackwell Scientific Publications, 20-62.
Fatmi, A. N.; 1973. Lithostratigraphic units of Kohat-Potwar Province, Indus Basin Pakistan. Geol. Surv. Pakistan Mem., 10.
Fielding, C. R., 1986. Fluvial channel and overbank deposit from the Westphalian of the Durham coalfield, NE England. Sedimentology, 33, 119-140.
Friend, P. F., 1978. Distinctive features of some ancient river systems. In: Fluvial sedimentology (A.D. Maill, ed.). Canada. Soc. Petrol. Geol. Mem., 5, 531-542.
Galloway. W. E., 1985. Meandering streams Modern and Ancient. The spectrum of fluvial systems. In recognition of fluvial depositional systems and their resource potential. SEPM short Course, 19, 145-166.
Harms J. C., Southhard J. B., Spearing D. R. & Walker R. G., 1975. Depositional environment as interpreted from primary sedimentary structures and stratification sequences. Short course Soc. Econ. Paleont. Miner., Dallas, 2, 161 p.
Meissner, C. R., Jan. M. M., Rashid, M. A. & Hussain, M., 1974. Stratigraphy of the Kohat Quadrangle, Pakistan - USGS Prof. Paper 716D, 1-30.
Miall, A. D., 1985. Architectural element analysis, a new method of facies analysis applied to fluvial deposits. Earth Sci. Rev., 22, 261-308.
Moody-Stuart, M., 1966. High and low sinousity deposits with examples from the Devonian of Spitzbergcn. J. Sedim. Petrol., 36, 1 1021117.
Plint, A.G., 1983. Sandy fluvial point bar sediments from the middle Eocene of Dorset. England. In: Modern and ancient fluvial systems (J. D. Collinson & J. Lewin eds.) Spec. Publ. Int. Ass. Sedimentology, 6, 355-368.
Powell, C. M., 1979. A speculative tectonic history of Pakistan and surrounding: Some Constraints from the Indian ocean. In: Geodynamics of Pakistan. (A. Farah & K. DeJong eds.). Geol. Surv. Pakistan, Quetta, 5-24.
Reineck, H. E. & Singh, I. B., 1980. Depositional Sedimentary Environments- with Reference to Terrigenous clastics; (2nd edition) Springer Verlag, Berlin, 549p.
Shah, I., 1977. Stratigraphy of Pakistan. Geol. Surv. Pakistan Mem., 12.
Stewart, D. J., 1981. A meander belt sandstone of the lower cretaceous of southern England. Sedimentology, 28, 1-20.
Walker, R. G. & Cantt, D. J., 1984. sandy fluvial systems. In: Facies models. Geosci. Can., reprint series, 1, 71-89.
