Abstract
Anorthosite-gabbro-granite-granophyre suite of rocks occurring in the Precambrian migmatitic gneiss of Cannanore district, Kerala and spatially related to the Bavali lineament, constitute the Ezhimala igneous complex (EIC). The granophyres exhibit typical cuneiform and radiating fringe-type intergrowths. Geochemistry indicates a tonalitic—trondhjemitic to granitic composition of the residual magma. Petrochemical characters and lithologic association suggest that the EIC represents a complete differentiation sequence derived by strong fractionation and crystal cumulation of a parent basaltic magma which followed a tholeiitic differentiation trend, with no significant crustal participation as implied by the low initial strontium isotope levels. Occurrence of the complex along the Bavali lineament, which is a major rift-zone, emphasises a rift-controlled magmatism in this part of the Indian shield.
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References
Barker D S 1970Bull. Geol. Soc. Am. 81 3339
Barker F and Arth J G 1976Geology 4 596
Cerny P 1971Contr. Mineral. Petrol. 30 343
Coleman R G and Donato M M 1979 inDevelopments in petrology (ed.) F Barker (Amsterdam: Elsevier)6 149
Coleman R G and Peterman Z E 1975J. Geophys. Res. 80 1099
Dunham A C 1968Q. J. Geol. Soc. London 123 327
Glikson A Y and Sheraton J W 1972Earth Planet. Sci. Lett. 17 227
Goode A D T 1977Earth Planet. Sci. Lett. 34 375
Hanson G N 1978Earth Planet. Sci. Lett. 38 26
Leighton M W 1954Bull. Geol. Soc. Am. 65 401
Lofgren G 1971Bull. Geol. Soc. Am. 82 111
Marmo V 1971Granite petrology and the granite problem (Amsterdam: Elsevier) p. 244
Nair M M and Vidvadharan K T 1982J. Geol. Soc. India 23 46
Nair N G K and Santosh M 1983J. Geol. Soc. India (in press)
Parsons I 1972Medd. om Gronland 195 73
Santosh M and Nair N G K 1983J. Geol. Soc. India 24 291
Turner F J and Verhoogen J 1961Igneous and metamorphic petrology (New York: McGraw Hill) 694
Tuttle O F and Bowen N L 1958Geol. Soc. Am. Mem. 74 1
Varadan G N and Venkataramana B 1976Ind. Minerals 30 96
Varadan G N, Venkataramana B and Viswanathan T V 1976Symp. Paleovolcanicity, associated tectonism and metallogeny in India (Ind. Acad. Geosciences, Hyderabad). p. 31
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Nair, N.G.K., Santosh, M. Petrochemistry of granite and granophyres of the Ezhimala igneous complex, Kerala, India. Proc. Indian Acad. Sci. (Earth Planet Sci.) 92, 129–140 (1983). https://doi.org/10.1007/BF02866735
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DOI: https://doi.org/10.1007/BF02866735