Neutron activation studies of refractory siderophile element anomaly and other trace element patterns in boundary clay between Permian/Triassic, Changxin, China

Although Ir anomaly was discovered in a number of C/T boundaries in the world, no positive results of this anomaly in Permian/Triassic (P/T) boundary were given. There are many well-developed P/T sections in South China. Ir, Os, Re, Au, Pt, Cu and Mo were determined by the radiochemical procedure developed in the authors' laboratory. The results reveal that the refractory siderophile and other chalcophile elements have certain enrichment near and at the boundary layer. However, the Ir/Au and other element abundance ratios fail to accord with the extraterrestrial values. The nature of the boundary event was discussed in terms of elemental geochemistry. (author) 22 refs