The first Sm-Nd isotopic data for metamorphic rocks of the Gudjal block in the eastern part of Bureya continental massif

Abstract

It is the first time that there have been Sm-Nd isotopic geochemical studies conducted into the metamorphic rocks of the Gudjal block considered as a basement protrusion of the Bureya continental massif. It has been found that biotite and garnet-amphibole schists of the Gudjal formation are characterized by strongly negative εNd(0)=–15.7…–17.2 values and Paleoproterozoic values of Nd model age of tNd(DM)=2.4–2.1 Ga. Similar isotopic parameters are also typical of gneissic biotite granodiorites: εNd(0)=–18.7, tNd(DM)=1.8 Ga. Out of orthorocks of the Gudjal block studied, the Neoproterozoic orthogneisses and orthoamphibolites of the Tulovchikha formation and the Neoproterozoic gneiss-granites of the Nyatyngran complex of the Paleoproterozoic model age may be considered as a probable substrate for melts.