Abstract
The massif anorthosites and gabbros occurring in the north Kerala region are localised along the Bavali fault. Several other bodies of granophyres and syeites also occupy this fault. All these bodies are considered to be a continuous graduating igneous series. This paper aims at delineating the field relations, petrochemistry and origin of massif anorthosites and gabbros occurring in the vicinity of the fault.
Anorthosites (An 70-55) are nonlayered and highly deformed with no igneous structure present. Gabbros show relict poikilitic texture with a mineralogy of plagioclase, clinopyroxene, hornblende and biotite. Geochemical study suggests dominantly calc-alkaline characteristics for both anorthosites and gabbros. However, their chemical variation is not transitional to indicate evolution by continuous differentiation from a single parent magma. The rock types seem to be chemically unrelated and appear to have evolved independently from discreet magma sources and the magma migration might have only been promoted by the Bavali lineament.
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References
Barker F and Arth J G 1976Geology 4 596
Bridgwater D and Windley B F 1973Geol. Soc. South Africa (Spec. Publ.)3, 307
De Anirudda 1969N. Y. State Mus. Sci. Serv. Mem. 18, 425
Duke J M 1976J. Petrol. 17 499
Irivine T N and Bargar W R 1971Can. J. Earth Sci. 8 523
Isachaen Y W 1969N. Y. State Mus. Sci. Serv. Mem. 18, 435
Kuno H 1966Bull. Volcanol. 29 196
Manson V 1967 inBasalts—the Poldervaart treatise on rocks of basaltic composition (New York: Inter-Science)
Morse 1982Am. Mineral. 67 1087
Nair M M and Vidyadharan K T 1982J. Geol. Soc. India 23 46
Naqvi S M and Hussain S M 1979Can. J. Earth Sci. 16, 1254
Ravindra Kumar G R 1984Abstract IGC, Moscow
Ravindra Kumar G R and Sinha-Roy S 1986Indian mineral.
Sarkar A, Bhanumati L and Balasubramanyam M N 1981Lithos 14, 93
Sinha-Roy S and Ravindra Kumar G R 1986J. Geol. Soc. India
Subramaniam A P 1956Geol. Soc. Am Bull. 67, 317
Vidyadharan K T, Sukumaran P V and Nair M M 1977J. Geol. Soc. India 18, 519
Wiebe A R 1980Nature (London) 286 564
Windley B F 1973Geol. Soc. Aust. (Spec. Publ.)3 319
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Kumar, G.R.R. The petrology and geochemistry of massif anorthosites and gabbros of the Bavali fault zone, North Kerala. Proc. Indian Acad. Sci. (Earth Planet. Sci.) 95, 117–130 (1986). https://doi.org/10.1007/BF03029176
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DOI: https://doi.org/10.1007/BF03029176