U-Pb Dating of the Baddeleytte-Zircon System from Pt-Bearing Dunite of the Konder Massif, Aldan Shield: New Data

摘要

The U-Pb age was obtained for the coexisting baddeleytte-zircon system from dunites of the Konder massif, Aldan shield. Four groups of zircons are heterogeneous by morphology, habit, age, and geochemistry in contrast to homogeneous baddeleytte. The studied zircon groups are characterized by several U-Pb age clusters in the range of 1895 ± 50 to 125.8 ± 3.8 Ma, which indicates their long evolution in Pt-bearing dunites. The young assemblage of baddeleytte and zircon (124.9 ± 1.9 and 125.8 ± 3.8 Ma, respectively) also differs from ancient zircons in the morphology and geochemistry and probably dates to a much later event of diapir evolution, which may be referred to the formation of apatite-phlogopite ore pyroxenites inside the dunite core and tectono-magmatic activation of the Aldan shield.