Application of multi-element relationships in stream sediments to mineral exploration: a case study of Walawe Ganga Basin, Sri Lanka

This study on the application of multi-element relationships in stream sedi ments to mineral exploration in the Walawe Ganga Basin presents one of the first of its kind in Sri Lanka. In order to determine the nature of these s ediments, multi-element analysis of selected grain size (<63 <mu>m, 63-125 mum, 125-177 mum and 177-250 mum) fractions was undertaken. The chemical co mposition of these fractions were compared with those of the upper continen tal crust. Some elements, notably Zr, Hf, Th, U, Ce and La, show very high enrichment factors (e.g. 54 for Zr) as compared to the upper crustal abundance. These are presumably associated with heavy minerals such as zircon, rutile and mo nazite found in abundance in the stream sediments of the Walawe Ganga Basin . Principal Component Analysis (PCA) of the geochemical data show that multi- element relationships could be effectively used to delineate target areas f or mineral exploration. With the use of PCA, this study reveals that areas with associations of calc-silicate/marble and charnockitic rocks are probab le source regions for mineral occurrences, particularly in the axial region s of anticlines. (C) 2000 Elsevier Science Ltd. All rights reserved.