ABSTRACT

Combined geological and geochemical evidence suggests that the age of the basement through which the Wudalianchi, Erkeshan, and Keluo (WEK) volcanic rocks in NE China were erupted is post-Archaean. Sr, Nd, and Pb isotope analyses demonstrate that the Miocene to Recent WEK potassic volcanic rocks were derived from an enriched mantle source which had been metasomatised during the Proterozoic. The primary potassic magmas are the products of partial melting of either this enriched mantle source or, more probably, a mixture of this enriched source with an OIB source. In either case, a post-Archaean subcontinental lithospheric mantle with an EM1 signature has made a significant contribution to the WEK potassic rocks.