FIRST DATA ON EARLY CRETACEOUS PEGMATITES IN WESTERN TRANSBAIKALIA Rb-Sr dating)
M. G. Shadaev, V. F. Posokhov, and G. S. Ripp
Keywords: Rb-Sr isotope dates, granite pegmatites, Early Cretaceous, Transbaikalia
Pages: 1421-1424
Abstract
We performed Rb-Sr isotope dating of dikes of granite pegmatites breaking through the alkali gabbroids and syenites of the Oshurkovsky Massif. The refined age of the massif is 125 Ma. Pegmatites form a field including several tens of bodies. We have established that the pegmatites formed in two stages: 113  2 Ma and 120 2.4 Ma ago. Pegmatites of these intrusion stages differ in geochemical features. The close ratios of Sr isotopes in the pegmatites of the first stage and in the massif gabbroids suggest participation of alkaline-basaltic magmas in granitoid pegmatite formation. |
