ISOTOPIC GEOCHEMICAL DATA ON THE NATURE A ND AGE OF THE ENDOGENEOUS CARBONATE ROCKS OF ZABAIKALYE

The carbonatitic origin of ore bearing endogeneous carbonate rocks was established by use of the isotopic studies and geological materials. These rocks could be correlated with the carbonatites of the ''linear' ' type. Strontium isotopic composition studies indicated that these ro cks could be formed as a product of mantle fluid substitution of crust al matter. Rb-Sr isochrone age of carbonatites was first carried out a nd assumption of possible association of carbonatites with alkaline ba sic rocks was advanced.