REEVALUATION OF THE HOMOGENEITY OF REE, TH AND U IN GEOCHEMICAL REFERENCE ZIRCON 61.308B

In a previous study of the reference sample zircon 61.308B, it has bee n suggested that either the sample is heterogeneous or inter-method co mparisons introduce analytical dispersions. New determinations by LA-I CP-MS show relative standard deviation in the order of 20% for Heavy R are Earth Elements (HREE). This is four times the variation attributab le to analytical method. A possible explanation is that HREE concentra tion variations in geochemical reference zircon were created by crysta l fractionation or oscillatory variation in the host magma. This confi rms that zircon 61.308B is heterogeneous for trace elements.