Rubidium-strontium age of fault-line alkaline metasomatites and granites of the Tatar-Penchenginsky zone (Yenisei Ridge)

Results of Rb-Sr datings, which have been made for the first time for fault-line alkaline metasomatites and granites of the Tataro-Penchenginsky zone, are presented. It is shown, that in the metasomatites and carbonatitoids strontium content is high (1200-9100 g/t) and rubidium one is low (7-240 g/t), Rb/Sr < 0.5. Initial isotope ratio in granites (87Sr/86Sr)0 equals 0.7104+-0.0009. Isochronous age of the metasomatites is 650+-2 mln.years, and that of granites is 601+-9 mln.years, i.e. fault-line alkaline metasomatites and granitoids of the Tataro-Penchenginsky zone were formed in the Vend and are separated by a small age difference in 50-60 mln.years