High-P Rocks Along the Suture Zones Around Indo-Pakistan Plate and Phase Chemistry of Blueschists from Eastern Ladakh
Abstract
The Indus-Zangbo suture zone (IZS), the Indoburman suture zone and the Chaman Fault are the traces of major collisional boundaries between the Indo-Pakistan plate and Eurasian block, Gondwanic microcontinents or island arcs. These suture zones are characterized in several places by ophiolites and tectonic melanges. High-P metamorphic rocks, generally belonging to blueschist facies, have recently been discovered along the suture zones in Naga hills, southern Tibet, eastern and western Ladakh, Swat and Afghanistan. The High-P metamorphism probability occurred during the Late Cretaceous/Paleocene. In the IZS it is complemented by low- to medium-P metamorphism to the north, suggesting a northward dip for the subduction zone. Along the southern margin of the Kohistan arc near Jijal, immediately N of IZS, gabbroic rocks were metamorphosed to High-P garnet granulites at a depth of > 40 km about 100 m.y. ago.
Detailed investigations, based on whole rock- and 188 point, analyses in three sections, suggest that metabasites in the eastern Ladakh ophiolite melange are ocean floor basalts metamorphosed under blueschist facies conditions. They are mineralogically similar to high-grade blueschists of other areas and contain sodic, sodic-calcic and calcic amphiboles, epidote, chlorite, albite, phengite, paragonite, garnet, quartz, futile, calcite, and magnetite. The PT trajectory suggests that the metamorphic conditions culmiated around 370-480 oC, 7-8 kbar and subsequent retrogression, possibly during uplift, took place at similar temperature but lower (6-4 kbar) pressure.
References
Agrawal, O.P. & Kacker, R.N., 1980. Nagaland ophiolites - a subduction zone ophiolite complex in a Tethyan orogenic belt. In (Panayioutou. A. ed). Proceedings, International Ophiolite Symposium, Cyprus, 1979. Geological Survey Department, Cyprus, 455-461.
Ashworth, J.R. & Evirgen, M., 1984. Garnet and associated minerals in the southern margin of the Menderes Massif, southern Turkey. Geol. Mag. 121, 323-337.
Andrews-Speed, C.P. & Brookfield, M.G., 1982, Middle Paleozoic geology and tectonic evolution of northwestern Himalaya. Tectonophysics 82, 253-275.
Bard, J.P., 1983. Metamorphic evolution of an obducted island arc: example of the Kohistan sequence (Pakistan) in the Himalayan collided range. Geol. Bull. Univ. Peshawar 16, 105-184.
Black, P.M., 1973. Mineralogy of New Caledonian metamorphic rocks II. Amphiboles from the Oneqoa district. Contrib. Mineral. Petrol. 39, 55-64.
Brothers, R.N., 1974. High-pressure schists in northern New Caledonia. Contrib. Mineral. Petrol. 46, 109-127.
Brown, B.H., 1974. Comparison of the mineralogy and phase relations of blueschists from the North Cascades, Washington, and greenschists from Otago, New Zealand. Geol. Soc. Amer. Bull. 35, 333-344.
Brown, B.H., 1977. The crossite content of Ca-amphibole as a guide to pressure of metamorphism. Jour. Petrol. 18, 53-72.
Chatterjee, N.D., 1972. The upper stability limit of the assemblage paragonite+ quartz and its natural occurrences. Contrib. Mineral. Petrol. 34, 288-303.
Chopin, C. & Maluski, H., 1980, 40Ar/39Ar dating of high-pressure metamorphic micas from the Gran Paradiso area (Western Alps): Evidence against the blocking temperature concept. Contrib. Mineral. Petrol. 74, 109-122.
Cipriani, C., Sassi, F.P. & Scolari. A., 1971. Metamorphic white micas: Definition of paragonite fields. Schewiz Mineral. Petrogr. Mitt. 55, 259-302.
Coleman, R.G., 1967, Glaucophane schists from California and New Caledonia. Tectonophysics 4, 479-498.
Coleman, R.G., & Lee, D.E., 1963: Glaucophane-bearing metamorphic rock types of the Cazadero area, California. Jour. Petrol. 4, 260-301.
Coleman, R.G., and Papike, J.J., 1866. Alkali amphiboles from the blueschists of Cazadero, California. Jour. Petrol. 9, 105-122.
Cooper, A.F., 1972. Progressive metamorphism of metabasic rocks from the Haast schist group of Southern New Zealand. Jour. Petrol. 13, 457492.
Coward, M.P., Jan, M.Q., Rex, D., Tarney, J., Thirlwall, M. & Windley, B.F., 1982. Geotectonic framework of the Himalaya of N. Pakistan. Jour. Geol. Soc. 139, 299-308.
Coward, M.P., Windley, B.F., Broughton, R., Luff, I.W., Petterson, M., Pudsey, C., Rex, D. & Khan, M.A., 1485. Collision tectonics in the NW Himalaya. Jour. Geol. Soc. 142 (in press).
Davies, R.G., 1962. A green beryl (emerald) near Mingora, Swat State: Geol. Bull. Punjab Univ. 2, 51-52.
England, P.C. & Richardson, S.W., 1977, The influence of erosion upon the mineral facies of rocks from different metamorphic environments. Jour. Geol. Soc. 134, 20 1-213.
Emst, W.G., 1963. Significance of phengitic micas from low-grade schists. Amer. Mineral. 48, 1357-1373.
Emst, W.G., 1972. Ca-amphibole paragenesis in the Shirataki district, Central Shikoku, Japan. Geol. Soc. Amer. Memoir 135, 73-94.
Emst, W.G., 1977, Mineral parageneses and plate tectonic settings of relatively high-pressure metamorphic belts. Fortsch. Mineral. 54, 192-222.
Emst, W.G., 1979. Coexisting sodic and calcic amphiboles frim high-pressure metamorphic belts and the stability of barroistic amphibole. Min. Mag. 43, 269-278.
Emst, W.G., and Seki, Y., 1967. Petrologic comparison of the Franciscan and Sanbagawa metamorphic terranes. Tectonophysics 4, 463-478.
Emst, W.G., Onuki, H. & Gilbert, M.C., 1970. Comparative study of low-grade metamorphism in the California Coast Ranges and the outer Metamorphic Belt of Japan. Geol. Soc. Amer. Memoir, 124.
Forbes, R.B., Evans, B.W. & Thurston, S.P., 1984. Regional progressive high-pressure metamorphism, Seward Peniusula, Alaska. Jour. Metamorphic Geol. 2, 43-54.
Frank, W., Gansser, A. & Trornmsdorff, V., 1977. Geological observations in the Ladakh area (Himalaya) - a preliminary report. Schewiz Mineral. Petrogr. Mitt. 57, 89-113.
Frank, G., Althaus, E., 1977. The stability relations of the paragenesis paragonite-zoisitequartz. Neues Jahrb. Mineral. Abhand. 130, 159-167.
Frey, M., Hunziker, J.C., Jager, E. & Stem, W.D., 1983. Regional distribution of white K-mica polymorphs and their phengitic content in the Central Alps. Contrib. Mineral. Petrol. 83. 185-1 97.
Gansser, A., 1980a. The significance of the Himalayan suture zone. Tectonophysics 62, 37-52.
Gansser, A., 1980b. The peri-Indian suture zone. In Aubouin, A., Debelmas, J & Latreille, M., Coordinators, Geology of the Alpine chains born of the Tethys. B.R.G.M. Memoir 115, 140-148.
Ghent, E.D. & Stout, M.Z., 1981. Geobarometry and geothermometry of plagioclase-biotite, garnet-muscovite assemblage. Contrib. Mineral. Petrol. 76, 92-97.
Ghose, N.C. and Singh, R.N., 1980. Occurrence of blueschist facies in the ophiolite belt of Naga. hills, E of Kiphire, N.E. India. Geol. Rundsch. 69, 41 48.
Guiraud, M., Leyreloup, A.F. & Proust, F. (in preparation). Petrology of the galucophane bearing rocks from Khost, Afghanistan and from Kohistan, Northern Pakistan.
Hey, M.H., 1954. A new review of the chlorites. Mineral. Mag. 30, 277-292.
Haoruo, W. & Wanming, D., 1980. Basic geologic features of the Yarlung Zangbo ophiolite belt, Xizang. China. In Panayiotou, A., ed., Proceedings International Ophiolite Symposeurn, Cyprus, 1979. Geological Survey Department, Cyprus, 462-472.
Heinrich, W. & Althaus, E., Die obere stabilitagrenze von lawsonit plus albit bsw. Jadeit. Fortsch. Mineral. 58, 117-132.
Holdaway, M.J., 1972. Thermal stability of Al-Fe epidotes as a function of fez and Fe content. Contrib. Mineral. Petrol. 37, 307-340.
Holland, T.J.B., 1979. Experimental determination of the reaction paragonite = Jadeite + Kyanite + H2O and internally consistent thermodynamic data for part of the system Na2O- Al2O3-SiO2-H2O with application to ecologites and blueschists. Contrib. Mineral. Petrol. 68, 293-301.
Honegger, K., Dietrich, V., Frank, W., Gansser, A., Thani, M. & Trommsdorff, V., 1982. Maginatism and metamorphism in the Ladakh Himalaya (the Indus Tsangpo suture zone). Earth Planet. Sci. Letters 60, 253-292.
Jan, M.Q., 1980. Petrology of the obducted mafic and ultramafic metamorphites from the southern part of the Kohistan island arc sequence. Geol. Bull. Univ. Peshawar 13, 95-107.
Jan, M.Q., & Asif, M., 1983. Geochemistry of tonalites and (quartz) diorites of the Kohistan-Ladakh (Transhimalayan) granitic belt in Swat, NW Pakistan. In Shams, F.A., ed., Granites of Himalaya, Karakorum and Hindukush. Institute of Geol. Puniab Univ., Lahore, Pakistan, 355-376.
Jan, M.Q., & Howie, R.A., 1981. The mineralogy and geochemistry of the metamorphosed basic and ultrabasic rocks of the Jajal Complex, Kohistan, NW Pakistan. Jour. Petrol. 22, 85-126.
Jan, M.Q., & Howie, R.A., 1982. Hornblendic amphiboles from basic and intermediate rocks of Swat-Kohistan, N. Pakistan. Amer. Mineral. 67, 1155-1178.
Jan, M.Q., Kamal, M. & Khan. I., 1981. Tectonic control over emerald mineralization in Swat. Geol. Bull. Univ. Peshawar 14, 101-109.
Jan, M.Q., & Symes, R.F., 1977. Piemontite schists from Upper Swat, northwest Pakistan. Mineral. Mag. 41, 537-540.
Jan, M.Q., Wilson, R.N. & Windley, B.F., 1982. Paragonite paragenesis from the garnet granulites of the Jijal complex, Kohistan, N. Pakistan. Mineral. Mag. 45, 73-77.
Johannes, W, & Puhan, D., 1971. The calcite-aragonite transition, reinvestigated. Contrib. Mineral. Petrol. 31, 28-38.
Kazmer, C., Hussain, S.S. & Lawrence, R.D., 1983. The Kohistan-Indian plate suture zone at Jawan Pass, Swat, Pakistan. Geol. Soc. Amer. Abstracts with Programs, 15, 609.
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. Pakistan. Geol. Bull. Univ. Peshawar 17, 127-144.
Klootwijk, C., Sharma, M.L., Gergan, J., Tirkey, B., Shah, S.K. & Agrawal, V., 1979. The extent of greater India, II Paleomapetic data from the Ladakh intrusive and Kargil, NW Himalayas. Earth Planet. Sci. Letters 44, 47-64.
Kumar, S., 1981. Reply to Discussion on 'Presence of parallel metamorphic belts in the northwest Himalaya. Tectonophysics 72, 147-154.
Laird, J., 1982. Amphiboles in metamorphosed basaltic rocks: Greenschist facies to amphibolite facies, In Veblen, D.R. & Ribbe, P.H., eds., Amphiboles. Mineral. sot. America Reviews in Mineral. 9B, 113-138.
Laird, J., & Albee, A.L., 1981. Pressure, Temperature, and time indicators in mafic schists: Their application to reconstructing the polymetamorphic history of Vermont. Amer. Jour. Sci. 281, 127-175.
Leake, B.F., 1978. Nomenclature of amphiboles. Mineral. Mag. 42, 533-563.
Lee, D.E., Coleman, R.G. & Erd, R.C., 1963. Garnet types from the Cazadero area, California. Jour. Petrol. 4, 460-492.
Le Fort, P., 1975. Himalayas - The collided range. Present knowledge of the continental arc. Amer. Jour. Sci. 275A, 1-4.
Lieu, J.G., Ho, C.G. & Yen, T.P., 1975. Petrology of some galucophane schists and related rocks from Taiwan. Jour. Petrol. 16, 80-109.
Majid, M. & Shah, M.T., 1985. Mineralogy of a blueschist facies metagraywacke from Shergarh Sar area, Allai Kohistan, northern Pakistan. Geol. Bull. Univ. Peshawar (this vol.).
Maluski, H. & Matte. P., 1984. Ages of alpine tectonometamorphic events in the northwestern Himalaya (northern Pakistan) by 39Ar140Ar method. Tectonics 3, 1-18.
Mitchell, A.H.G., 1981. Phanerozoic plate boundaries in mainland SE Asia. the Himalayas and Tibet. Jour. Geol. Soc. 138, 109-122.
Miyashiro, A., 1975. Volcanic rocks series and tectonic settings. Annual Rev. Earth Planet. Sci. 3, 261-269.
Miyashiro, A., & Banno, S., 1958. Nature of galucophanitic metamorphism. Amer. Jour. Sci. 256, 97-110.
Miyashiro, A., & Shido, F., 1973. Progressive compositional charges of garnet in metapelite, Lithos 6, 13-20.
Moore, D.E., 1984. Metamorphic history of a high-grade blueschist exotic block from the Franciscan complex, California. Jour. Petrol. 25, 126-1 50.
Muir Wood, R., 1980. Compositional zoning in sodic amphiboles from the blueschist facies. Mineral. Mag. 43, 741-752.
Nicholas, A et al. (8 authors), 1981. The Xigaze ophiolite (Tibet): a peculiar oceanic lithosphere. Nature 294, 414-417.
Nitsch, K.H., 1968. Die stabilitat won lawsonit. Naturwise 8, 388-389.
Nitsch, K.H., 1971. Stabilitatsbeziehungen von prehnit-und pumpellyit-haltigen paragenesen. Contrib. Mineral. Petrol. 30, 240-260.
Nitsch, K.H., 1972. Das P-T-XCO3- stabilitatsfeld von lawsonit. Contrib. Mineral. Petrol. 34, 116-134.
Panayiotou, A. (ed.). 1980. Ophiolites, Proceedings International Ophiolite Symposeum, Cyprus, 1979: Nicosia, Cyprus, Geological Survey Department.
Pearce, J.A., 1975. Basalt geochemistry used to investigate past tectonic environments on Cyprus. Tectonophysics 25. 41-67.
Pearce, J.A., 1982. Trace element characteristics of laves from destructive plate boundaries. In Thorpe. R.S., ed., Andesistes. New York, John Wiley and Sons, 525-548,
Pearce, J.A., 1983. (Unpublished). A 'users guide' to basalt discrimination diagrams.
Perchuk, L.L., 1966. Temperature dependence of the coefficient of distribution of calcium between coexisting amphibole and plagioclase. Doklady Acad. Sci. USSR. Earth Sciences Sect. 169, 203-205.
Powell, C. McA. & Conaghan, J.P., 1973. Plate tectonics and the Himalayas. Earth Planet. Sci. Letters, 20. 1-12.
Ramsay, C.R., 1973. Controls of biotite zone mineral chemistry in Archaean metasediments near Yellow Knife. Northwest Territories, Canada. Jour. Petrol. 14, 467-488.
Shackleton, R.M., 1981. Structure of southern Tibet: report on a traverse from Lhasa to Khatmandu organized by Academia Sinica. Jour. Structural Geol. 3, 97-105.
Shams, F.A., 1972, Galucophane-bearing rocks from near Topsin, Swat - First record from Pakistan. Pakistan Jour. Science 24, 343-345.
Shams, F.A., 1980. Origin of the Shangla blueschists, Swat Himalaya, Pakistan. Geol. Bull. Univ. Peshawar 13, 67-70.
Sharma, K.K. & Gupta. K.R., 1983. Calc-alkaline island arc volcanism in Indus-Tsangpo suture zone. In Thakur, V.C., and Sharrna, K.K., eds., Geology of Indus Suture Zone of Eastern Ladakh. Dehra Dun: Wadia Institute of Himalayan Geology, 71-78.
Sinha Roy, S., 1975. Blueschist facies metamorphism in Daling rocks from a part of KaIimpong Hills, eastern Himalayas. Jour. Geol. Soc. India 16, 275-286.
Spear, F.S., 1980. NaSi = CaAl exchange equilibrium between plagioclase and amphibole. Contrib. Mineral. Petrol. 72, 33-41.
Spear, F.S., 1982. Calcic amphiboles and sodic amphiboles. In Vebelen, D.R., and Ribbe, P.H., eds., Amphiboles, Mineral, Soc. Amer. Reviews in Mineral. 9B, 82-88.
Stensrud, H.L., 1973. Discussion on 'Does piedmontite represent only greenschist facies metamorphism?'. Contrib. Mineral. Petrol. 40, 79-82.
Tahirkheli, R.A.K., Mattauer, M., Proust, F. & Tapponnier, P., 1979. The India-Eurasia suture zone in northern Pakistan: Some new data for interpretation at plate scale. In Farah. A., and De. Jhong, K.A., eds., Geodynamics of Pakistan. Geological Survey of Pakistan, 125-139.
Takasu, A., 1984. Prograde and retrograde eclogites in Sanbabawa metamorphic belt, Besshi district, Japan. Jour. Petrol. 25, 619-4543.
Tapponnier, P., Mattauer, M., Proust, F. & Cassaignau, C., 1981. Mesozoic ophiolites sutures and large scale tectonic movements in Afghanistan. Earth Plant. Sci. Letters. 52, 353-371.
Thakur, V.C. and Bagati, T.N., 1983. Indus Formation; An arc-trench gap sediments. In Thakur. V.C. and Sharma, K.K., eds. Geology of Indus Suture Zone of Eastern Ladakh. Dehra Dun: Wadia Institute of Himalayan Geology. 2 1-3 1.
Thakur, V.C. & Bhat, M.I., 1983. Interpretation of tectonic environment of Nidar ophiolite: a geochemical approach. In Thakur, V.C. and Sharma, K.K., eds. Geology of Indus Suture Zone of Eastern Ladakh. Dehra Dun: Wadia Institute of Himalayan Geology, 3340.
Taylor, H.P., Jr. & Coleman. R.G., 1968. O18/016 ratios of coexisting minerals in galucophane-bearing metamorphic rocks. Geol. Soc. Amer. Bull. 79, 1727-1756.
Tracy. J.R., Robinson, P. & Thompson, A.B., 1976. Garnet composition and zoning in the determination of temperature and pressure of metamorphism, Central Massachusetts. Amer. Mineral. 61, 762-775.
Velde, B., 1965. Phengite micas: synthesis, stability and natural occurrence. Amer. Jour. Sci. 886-913.
Velde, B., 1967. Si+ 4 content of natural phengites. Contrib. Mineral. Petrol. 14, 250-258.
Virdi, N.S., 1981a. Occurrence of paired-metamorphic belts in the Himalaya. Jour. Geol. Soc. India, 22, 547-554.
Virdi, N.S., 1981b. Discussion on 'Presence of parallel metamorphic belts in north-west Himalaya'. Tectonophysics 72, 141-146.
Virdi, N.S., Thakur, V.C. & Kumar, S., 1977. Blueschist facies metamorphism from the Indus suture zone of Ladakh and its significance. Himalayan Geol. 7, 479-482.
Whitney. J.A. & Stormer, J.C., Jr., 1977. Two-Feldspar geothermometry. geobarornetry in mesozonal granitic intrusions. Three examples from the Piedmont of Georgia. Contrib. Mineral. Petrol. 63, 51-44.
Xiao, X. & Gao, Y., 1982. New finds of the high-pressure and low tempsratute greenschist facies from Yarlung Zangbo (Tsangpo) suture zone, Xizang (Tibet). Bull. Inst. Geol. Chinese Acad. Sci. 5, 77-79. (extracted from Mineralogical Abstracts 84M/2269).
Zhang, Q., Li, D. & Li, S., 3980. A pair of metamorphic belts in south Yizang (Abs). Proceedings of symposeum on Qinghai Xizang (Tibet) Plateau. Academia Sinica, 31-32.
Zhang, Q., Zhang, Z. & Li, S., 1980. Muscovite of metamorphic rocks in east and south Xizang and its petrological significance. Scientia Geol. Sinica, 340-347.
Zhou, Y., Nu. H., Zheng, X., Wang, D., Zhang, Q., Li, D. & Zhang, X., 1982. Geology of the ophiolite in Xigase prefracture of southern Xizang (Tibet) China. Scientia Ged Sinica, 30-40 (extracted from Mineralogical Abstracts 82M14863).
Zhou, Y., Zhang, Q., Jin, C. & Deng, W., 1981. The migration and evolution of magmatism and metamorphism in Xizang since cretaceous and their relation to the Indian plate motion. A possible model for the uplift of the Qinghai-Xizang plateau. In Geological and Ecological studies of the Qinghai-Xizang plateau, 1. Sci. Press Beijing & Gordon and Breach, N.Y. 363-378.
