SM-ND ISOTOPIC SYSTEMATICS OF THE KURUMKAN SUBGROUP, THE IENGRA GROUPOF ALDAN SHIELD

The first data on the Nd isotopic composition in high-Al gneisses and associated garnet-hypersthene-biotite plagiogneisses of the Kurumkan S ubgroup, the Iengra Group of Aldan Shield are presented. The obtained results show that rocks of the subgroup accumulated after similar to 2 .9 Ga, i.e., during the Late Archean or Early Proterozoic, and not the Early Archean evolutionary stage of the shield. Protoliths of garnet- hypersthene-biotite gneisses were not older than 2.3 Ga, and their for mation marks the Early Proterozoic stage of continental crust generati on in the Aldan granulite-gneiss region.