Authors and Affiliation: G.R. Ravindra Kumar & C. Sreejith, Centre for Earth Science Studies, Thuruvaikkal P.O., Thiruvananthapuram 695031, Kerala, India
Journal: Indian Journal of Geo-Marine Sciences, Vol. 39 (4), December 2010, pp. 562-571
Abstract: Beach sediments of the Kerala coast contain rich economically important heavy mineral deposits. Most previous studies have traced the source of heavy minerals to the Precambrian crystalline formations in the hinterland based on comparative mineral occurrences. No previous study has attempted to utilize petrological and geochemical characteristics and mineral chemistry of source rocks to effectively compare and determine sediment provenance. A clear knowledge on the composition of minerals from source and sink is important in precise recognition of source rock. Present study consists the geological, geomorphologic setting and mineralogical characteristics of hinterland rocks to trace their connection to placer deposits. It is recognized that garnet as the abundant heavy mineral in the placer sediments and in source rocks of different ages and petrogenetic affinity. Garnet composition varies between different source rock types due to its strong dependency on the bulk rock composition. In order to decipher the provenance we have compared major element composition of garnet in the source rocks and placer deposits. Compelling similarities in mineralogical and mineral chemical characteristics of garnets (Alm68Prp28Grs3Sps1) is noted between khondalites and placer sediments suggesting latter as major source rock for placer deposits of southern Kerala. The study demonstrates excellent potential of garnets in identifying placer mineral source.
No comments:
Post a Comment