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Authors
Affiliations
1 Department of Geology, Presidency College, Calcutta, IN
2 Department of Atomic Energy, Atomic Minerals Division, Petrology Laboratory, New Delhi, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 10, No 2 (1969), Pagination: 167-176
Abstract
Geochemical data for 20 igneous rock samples from alkali complex of Koraput, Orissa are presented and discussed. Trace element contents in 8 individual minerals separated from the rock members have been estimated. The abundances of rare alkali earth metals are distinctly higher in early basic and intermediate members compared to those in a calcalkali suite. Some diadochic element ratios reveal a pronounced change of the variation trends at the ultimate end of the fractionation process. The granitophilc elements are not so remarkably enriched in the late differentiates as expected in low melting temperature constituents. Unlike feldspathoidal syenites of agpaitic complex, the nepheline syenite of Koraput is poor in niobium and zirconium.