Instrumental neutron activation analysis for rare earth elements in dolerite dykes of Kuantan area, Peninsular Malaysia

The REE abundances in five dolerite dykes (olivine tholeiite to quartz tholeiite) from Kuantan have been determined by instrumental (non-destructive) neutron activation analysis using reactor irradiation and high-resolution gamma-ray spectroscopy. The analytical procedures followed in this work are discussed. A total of nine rare earths (La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu) have been measured. The dykes show fractionated REE patterns with chondrite-normalised values ranging from about 34 to 105 for La and from about 8 to 11 for Yb. The concentrations of individual elements as well as the ?REE increase systematically with increasing differentiation. The more evolved rocks show positive Eu anomaly. The variations in REE abundances are compatible with a crystal fractionation (clinopyroxene and olivine) model of evolution interpreted from petrography and major element chemistry