OPTIMIZATION OF X-RAY-FLUORESCENCE ELEMENTAL ANALYSIS - AN EXAMPLE FROM KENYA

A systematic study and application of a radioisotope excited energy di spersive X-ray fluorescence analysis method to multi-elemental determi nation in Kenyan rock samples whose supporting matrices are of light e lements is presented. The method consists of instrumentation and analy tical parameter optimization, and an empirical background stripping mo del for reduced dark matrix scatter effects. The method was applied to trace, minor and major elemental determination in rock samples collec ted from various parts of Kenya in order to test it for routine minera l and geochemical prospecting in light element geological matrices. A correlative analysis of the samples revealed a common presence of elem ents: K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Ga, Au, Pb, Br, Rb, Sr, Nb, Zr, A s and Y in all five types of rocks, down to 3.0 mu g g(-1) for Br, wit h major differences revealed in the rock tectonic setting, origin, age and related palaeomagnetic parameters, and mineral enrichment prospec ts. (C) 1998 Elsevier Science Ltd. All rights reserved.