Precambrian Mafic Magmatism in the Himalayan Mountain Range
Authors
-
Department of Geology, Delhi University, Delhi - 110 007
Talat Ahmad
Keywords:
Magmatism, Precambrian, Himalaya.Abstract
Precambrian mafic magmatic rocks are restricted to the western Himalayas from Himachal in the west through Garhwal to Kumaun in the east. They occur as low-grade volcano-sedimentary sequences of the Lesser Himalaya in the form of volcanic flows intercalated with continentally derived sediments and also as dykes occurring as feeders and some traversing through these sequences. Thus, all the Precambrian mafic magmatic rocks are not contemporary but may represent more than one magmatic episode. However, it is not very clear how much is the gap between the individual magmatic phases. In addition to the low-grade sequences, mafic magmatic rocks are also recorded from the Chail, Jutogh and Vaikrita Groups and their equivalents in Garhwal and Kumaun regions. In these three sequences the mafic magmatic rocks are represented by amphibolites which occur as shapeless bodies, boudins, disrupted dykes/sills varying in size from 1-2 m in thickness and 3-5 m in width. The basic rocks of all the units consist of clinopyroxene (augite and ferro-augite) and plagioclases as the dominant phases with minor olivine (now serpentine). Commonly observed secondary phases include amphiboles, chlorite, opaques, epidote, quarts, biotite and titanites.
Geochemical data indicates that these rocks are compositionally basalt and basaltic - andesites. They have typical tholeiitic lineage with Fe-enrichment and are classified as low-Ti tholeiites. Rare earth elements (REE) and incompatible trace elements data indicate enriched light rare earth element (LREE) - large ion lithophile elements (LILE) and depletion of high field strength elements (HFSE) characteristics for the mafic rocks of the lower grade Lesser Himalayan sequences, Chail and Jutogh Groups. The mafic rocks of Vaikrita Group, on the other hand show nearly flat REE and incompatible trace elements patterns with distinct positive Sr-anomaly, which is very different from the other groups. These characteristics indicate derivation of Vaikrita mafic rocks from different sources compared to the other samples. Lithological association and geochemical characteristics indicate derivation of the mafic magmatic rocks from enriched lithospheric mantle sources by varying degrees of partial melting followed by clinopyroxene ± minor olivine ± plagioclases ± opaques in a rift tectonic environment.
Downloads
Issue
Section
Downloads
Published
How to Cite
References
AHMAD, T. and BHAT, M.I. (1987) Geochemistry and petrogenesis of the Mandi-Darla volcanics, northwestern Himalayas. Precambrian Res., v.37, pp.231-256.
AHMAD, T. and TARNEY, J. (1991) Geochemistry and petrogenesis of Garhwal volcanics: implications for evolution of the north Indian lithosphere. Precambrian Res., v.50, pp.69-88.
AHMAD, T., ISLAM, R., KHANNA, P.P. and THAKUR, V.C. (1996) Geochemistry, petrogenesis and tectonic significance of the basic volcanic units of the Zildat ophiolitic melange, Indus suture zone, eastern Ladakh (India). Geodinamica Acta, v.9, pp.222-233.
AHMAD, T., THAKUR, V.C., ISLAM, R., KHANNA, P.P. and MUKHERJEE, P.K. (1998) Geochemistry and geodynamic implications of magmatic rocks from the Trans-Himalayan arc. Geochemical Jour., v.32, pp.383-404.
AHMAD, T., MUKHERJEE, P.K. and TRIVEDI, J.R. (1999) Geochemistry of Precambrian mafic magmatic rocks of the western Himalaya, India: petrogenetic and tectonic implications. Chem Geol., v.160, pp.103-119.
AHMAD, T., HARRIS, N.B.W., BICKLE, M.J., CHAPMAN, H., BUNBURY, J. and PRINCE, C. (2000) Isotopic constraints on the structural relationships between the Lesser Himalayan series and the Higher Himalayan series, Garhwal Himalaya. Geol. Soc. Amer. Bull., v.112, pp.467-477
AHMAD, T., HARRIS, N.B.W., ISLAM, R., KHANNA, P.P., SACHAN, H.K. and MUKHERJI, B.K. (2005) Contrasting mafic magmatism in the Shyok and Indus Suture Zones: Geochemical constraints. Him. Geol., v.26, pp.33-40.
AHMAD, T., TANAKA, T., SACHAN, H.K. and MUKHERJEE, B.K. (2006) Petrogenesis of Coesite bearing Tso Morari eclogites: isotopic and elemental constraints. Jour. Asian Earth Sciences, v.26, p.121.
AHMAD, T. TANAKA, T., SACHAN, H.K., ASAHARA, Y., ISLAM, R. and KHANNA, P.P. (2007) Geochemical and isotopic constraints on the age and origin of the Nidar Ophiolitic Complex, Ladakh, India: Implications for the Neo-Tethyan subduction along the Indus Suture Zone. Tectonophysics (in press).
BHAT, M.I. (1984) Abor volcanics: further evidence for the birth of Tethys ocean in the Himalayan segment. Jour. Geol. Soc. London, v.141, pp.763-775.
BHAT, M.I. (1987) Spasmodic rift reactivation and its role in the pre-orogenic evolution of the Himalayan region. Tectonophysics, v.134, pp.103-127.
BHAT, M.I. and AHMAD, T. 1990. Petrogenesis and mantle source characteristics of the Abor volcanic rocks, Eastern Himalayas. Jour. Geol. Soc. India, v.36, pp.227-246.
BHAT, M.I. and AHMAD, T. (1987) Geochemistry and petrogenesis of Bhowali-Bhimtal volcanics, Kumaun Lesser Himalayas. Geosci. Jour., v.8, pp.51-61.
BHAT, M.I., LE FORT, P. and AHMAD, T. (1994) Bafliaz volcanics, NW Himalaya: origin of a bimodal, tholeiite and alkali basalt suite. Chem. Geol., v.114, pp.217-234.
BHAT, M.I. and LE FORT, P. (1992) Sm-Nd age and petrogenesis of Rampur metavolcanic rocks, NW Himalayas: Late Archaean relics in the Himalayan belt. Precambrian Res., v.56, pp.191-210.
BHAT, M.I., CLAESSON, S., DUBEY, A.K. and PANDE, K. (1998) Sm-Nd age of the Garhwal-Bhowali volcanics, western Himalayas: vestiges of late Archaean Rampur flood basalt province of the northern Indian craton. Precambrian Res., v.87, pp.217-231.
BHAT, M.I. and ZAINUDDIN, S.M. (1978) Geochemistry of the Panjal traps of Mount Koyol, Liddarwat, Pahelgam, Kashmir. Jour. Geol. Soc. India, v.19, pp.403-410.
BHAT, M.I. and ZAINUDDIN, S.M. (1982) Strontium-depleted nature of the Panjal traps in relation to lithospheric rift tectonics. Indian Jour. Earth Sci., v.9, pp.18-28.
BHAT, M.I., ZAINUDDIN, S.M. and RAIS, A. (1981) Panjal traps chemistry and the birth of Tethys. Geol. Mag., v.118, pp.367-375.
CHAUDHRI, N. and JOSEPH, B. (1997) Geochemistry and petrogenesis of the Palampur metavolcanics, Lesser Himachal Himalaya, India. Mineral. Petrol., v.59, pp.189-205.
CHAUDHRI, N. and JOSEPH, B. (1998) Geochemistry and origin of the mafic volcanic rocks of Dharamsala area, northwestern Himalaya, India. Chem. Erde, v.58, pp.271-289.
ERLANK, A.J., DUNCAN, A.R., MARSH, J.S., SWEENEY, R.J., HAWKESWORTH, C.J., MILNER, S.C., R. MCG. and ROGERS, N.W. (1988) A laterally extensive geochemical discontinuity in the subcontinental Gondwana lithosphere. In: Geochemical Evolution of Continental Crust. Conf. Abst. Procos de Caldes, Brazil, 11-16 July, 1988, pp.1-10.
HAWKESWORTH, C.J., GALLAGHER, K., PEARSON, G., TURNER, S.P. and CALSTEREN, V. (1993) The continental lithosphere: a geochemical perspective. An. Acad. Bras. Ci., v.65, pp.199-225.
INGER, S. and HARRIS, N.B.W. (1992) Tectonothermal evolution of the High Himalayan Crystalline sequence, Langtang Valley, northern Nepal. Jour. Metamor. Geol., v.10, pp.439-452.
ISLAM, R., AHMAD, T. and RAWAT, B.S. (2003) Geochemistry and petrogenesis of the Phe volcanics, Zanskar, Western Himalaya: bearing on the birth of Neo-Tethys. Mem. Geol. Soc. India, No.52, pp.339-357.
LAL, R.K., MUKHERJEE, S. and ACKERMAND, D. (1981) Deformation and Barrovian metamorphism at Takdah, Darjeeling (Eastern Himalaya). In: Saklani, P.S. (Editor) Metamorphic tectonites of the Himalaya. New Delhi. Today and Tomorrow's Publishers, pp.231-278.
MILLER, C., KLOTZLI, U., FRAN, W., THONI, M. and GRASEMANN, B. (2000) Proterozoic crustal evolution in the NW Himalaya (India) as recorded by circa 1.80 Ga mafic and 1.84 Ga granitic magmatism. Precambrian Res., v.103, pp.191-206.
MOHAN, A., WINDLEY, B.F. and SEARLE, M.P. (1989) Geothermobarometry and development of inverted metamorphism in the Darjeeling-Sikkim region of the eastern Himalaya. Jour. Metamor. Geol., v.7, pp.95-110.
REUBER, I. (1989) The Dras arc: two successive volcanic events on eroded oceanic crust. Tectonophysics, v.161, pp.93-106.
SAHAI, A. and SRIVASTAVA, R.K. (1997) Structural and Geochemical characteristics of Amphibolites from the Bhagirathi and Yamuna Valleys of Main Central Thrust Zone, Garhwal Himalaya. Jour. Himalayan Geol., v.18, pp.191-201.
SINHA, A.K. and MISHRA, M. (1992) Emplacement of the ophiolitic melange along continental collision zone of Indus suture zone in Ladakh Himalaya, India. Jour. Him. Geol., v.3, pp.179-189.
SHAH, S.K., SHARMA, T.R. and GUPTA, K.R. (1978) Trilobite trace fossils from the Bafliaz formation, western Pir Panjal and their significance. Jour. Geol. Soc. India, v.19: pp.273-276.
SHARMA, T.R. and GUPTA, K.R. (1975) Petrology and petrochemistry of spelite-keratophyre suite of Thannamandi area, Rajouri district, Jammu and Kashmir state. Geol. Surv. India Misc. Publ., v.24, pp.230-243.
SPENCER, D.A., TONARINI, S. and POGNANTE, U. (1995) Geochemical and Sr-Nd isotopic characterization of Higher Himalayan eclogites (and associated metabasites). Eur. Jour. Min., v.7, pp.89-102.
SRIKANTIA, S.V. (1977) The Sundernagar Group: its geology, correlation and significance as stratigraphically the deepest sediment in the Peninsular or Lesser Himalaya. Jour. Geol. Soc. India, v.18, pp.7-22.
SRIVASTAVA, R.K. and SAHAI, A. (2001) High-field strength element geochemistry of mafic intrusive rocks from the Bhagirathi and Yamuna valleys, Garhwal Himalaya, India. Gondwana Res., v.4, pp.455-463.
SRIVASTAVA, R.N. and AHMAD, A. (1979) Geology and structure of Alaknanda valley, Garhwal Himalaya. Him. Geol., v.9, pp.225-254.
SUN, S.S. and MCDONOUGH, W.F. (1989) Chemical and isotopic systematics of oceanic basalts: implications for the mantle composition and processes. In: A.D. Saunders and M.J. Norry, (Eds.), Magmatism in the Ocean Basins. Geol. Soc. London Spec. Publ., v.42, pp.313-345.
TARNEY, J. (1992) Geochemistry and significance of mafic dyke swarms in the Proterozoic. In: K.C. Condie (Ed.), Proterozoic Crustal Evolution, Ch. 4, Elsevier, Amsterdam, pp.151-179.
THAKUR, V.C. (1992) Geology of Western Himalaya. Pergamon, Oxford, 355p.
THAKUR, V.C. and MISRA, D.K. (1984) Tectonic framework of Indus and Shyok suture zones in eastern Ladakh, northwestern Himalaya. Tectonophysics, v.101, pp.207-220.
THOMPSON, R.N., MORRISON, M.A., DICKIN, A.P. and HENDRY, G.L. (1983) Continental flood basalts.Arachnids rule o.k.? In: C.J. Hawkesworth and M.J. Norry (Eds.), Continental Basalts and Mantle Xenoliths. Shiva Publ. Nantwich, pp.158-185.
VALDIYA, K.S. (1980) Geology of Kumaun Lesser Himalaya. Wadia Institute of Himalayan Geology, Dehradun, 291p.
VANNY, J.C. and HODGES, K.V. (1996) Tectonothermal evolution of the Himalayan metamorphic core between the Annapurna and Dhaulagiri, Central Nepal. Jour. Metamor. Geol., v.14, pp.635-656.
WEAVER, B.L. and TARNEY, J. (1981) The Scourie dyke suite: petrogenesis and geochemical nature of the Proterozoic subcontinental mantle. Contrib. Mineral. Petrol., v.78, pp.175-188
WEAVER, B.L. and TARNEY, J. (1983) The chemistry of the subcontinental mantle: inferences from Archean and Proterozoic dykes and continental flood basalts. In: C.J. Hawkesworth and M.J. Norry (Eds.), Continental Basalts and Mantle Xenoliths. Shiva Publ. Nantwich, pp.209-229.
WINCHESTER, J.A. and FLOYD, P.A. (1977) Geochemical distribution of different magma series and their differentiation products using immobile elements. Chem. Geol., v.20, pp.325-344.
YANN, R., PICARD, C., PECHER, A., LAPIERRE, H., BOSCH, D. and KELLER, F. (2002) The Cretaceous Ladakh arc of NW Himalaya-slab melting and melt-mantle interaction during fast northward drift of Indian plate. Chem. Geol., v.182, pp.139-178.
