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Authors
Affiliations
1 Department of Geology, University of Peradeniya, Peradeniya, LK
2 Uva Wellassa University of Sri Lanka, Passara Road, Badulla, LK
3 Department of Physics, The Open University of Sri Lanka, PO.Box 21, Nugegoda, LK
4 Institute of Earth Sciences, Karl-Franzens-University of Graz, Universitaetsplatz 2, Graz, 8010, AT
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 72, No 6 (2008), Pagination: 815-822
Abstract
Vertically and sub-vertically intruded syenite and granitic pegmatites, which carry many industrial minerals are found in the Owala-Kaikawala area in the central parts of Sri Lanka. The field setting, petrography and chemical composition of feldspars of these rocks illustrate that they have been derived from a single magmatic source formed by crustal anatexis. The enrichment of compatible elements in feldspars of the fluorite-bearing syenitic pegmatite and incompatible elements in granitic pegmatites can best be explained the chemical evolutions of the extremely fractionated melt. The initial fractionation of a volatile enriched, silica-undersaturated melt from the parental magma resulted into the fluorite-bearing syenitic pegmatite. The remaining melt that is rich in silica, fractionated again slightly and was emplaced into eastern parts of the area as granitic pegmatite. The fractionations of the fluid rich melt took place frequently until the crystallization of minerals.
Keywords
Pegmatite, Geochemistry of Feldspars, Incompatible Elements, Fractionation, Sri Lanka.
