Age of Ultrabasic Alkaline Rocks and Carbonatites of the Gornoozyorskii and Povorotny Massifs (Sette-Daban, Yakutia)

The Pb – Pb, Rb – Sr, K – Ar system of basite and carbonatite minerals from the Gornoozyorskii and Povorotny Massifs have been investigated. A great amount of analyses permitted the conclusion that the Gornoozyorskii Massif formed 460 to 320 Ma ago, and tectonomagmatic (metasomatic) activization occurred in the fault zones 170–150 Ma ago. The Povorotny Massif formed in the interval of 480–340 Ma. Not less than two phases of nepheline syenites (380–370 and 350 Ma) and two phases of carbonatites (390 and 370 Ma) are distinguished in both massifs. The δ13 C values of calcites, carbonatites and 87Sr/86Sr ratios of pyrochlores, apatites and calcites were determined. The conclusion was drawn that carbon dioxide and radiogenic strontium of ore-bearing magmatic carbonatites were generated from the mantle source.