Metamorphic mineral assemblages south of the Malakand and adjoining areas, northern Pakistan
Abstract
The mineral assemblages (calcite + muscovite + hornblende + quartz + plagioclase + zoisite + garnet) indicate epidote amphibolite facies conditions in the north near Mora Kandao south of the Malakand, north Pakistan. With the reported occasional occurrence of kyanite indicate that the metamorphism is probably of the medium pressure i.e., Barrovian type. Based on the mineral assemblages, temperatures of 580oC are assumed for the epidote amphibolite facies and pressures about 5.5 kb in the north.
The greenschist facies rocks in the south near Takht-e-Bhai, Rustam and surrounding, the mineral assemblage actinolite + biotite + muscovite + quartz + albite + magnetite and color index of conodont 5.5 to 7 suggesting peak metamorphic temperatures between 300 and 400oC and pressures up to 3 kb. Temperature and pressure for the melange blocks and matrix are assumed between 200 and 570oC with pressure 3 kbar.
References
Epstein, A.G. Epstein, J.B. & Harris, L.D., 1977. Conodont color alteration - an index to organic metamorphism. USGS Professional Paper 915.
Hamidullah, S., Jabeen, N., Bilqees, R. & Jamil, K., 1986. Geology and petrology of the Malakand granite, gneiss and metasedimentary complex. Geol. Bull. Univ. Peshawar, 25, 17-22.
Kazmi, A.H., Lawrence, R.D., Dawood, H., Snee, L.W., & Hussain, S.S., 1984. Geology of the Indus suture zone in the Mingora Shangla area of Swat, N. Paksitan: Geol. Bull. Univ. Peshawar, 17, 127-144.
Martin, N.R., Siddiqui, S.F.A., & King, B., 1962. A geological reconnaissance of the region between the lowre Swat and Indus River of Pakistan. Geol. Bull. Univ. Punjab, 2, 1-14.
Miyashiro, A., 1973. Metamorphism and nietamorphic belts: New York, Harper and Row, 514p.
Pogue, K.R., Wardlaw, B., Harris, A., & Hussain, A., 1992a. Paleozoic and Mesozoic stratigraphy of the Peshawar Basin, Pakistan: correlation implications: Geol. Soc. Am. Bull. 104, 915-927.
Rafiq, M. & Jan, M.Q., 1991. Titanium content of a chloritoid-quartz-ilmenite band in ophiolitic mélange near Prang Ghar, NW Pakistan. Geol. Bull. Univ. Peshawar, 24, 127-132.
Turner, F.J., 1981. Metamorphic Petrology: Mineralogical Field and Tectonic Aspects (Second edition): New York McGraw-Hill, 524p.
Wick, F.J. & O' Hanley, D.S., 1988. Serpentine minerals: structure and petrology. Mineral. Soc. Am., 19, 91-167.
