Early Jurassic Suprasubduction Granitoids of the Uda Complex at the Southwestern End of the Uda–Murgal Magmatic Arc: New Data on the Age and Sources

Granitoids of the Uda complex are developed within the southeastern marginal part of the Siberian craton and its folded framework. Geochemical, isotope–geochemical (Nd and Sr), and geochronological (U–Pb ID–TIMS) studies of a number of massifs of this complex were carried out for the Chogar granulite block of the Dzhugdzhur–Stanovoi superterrane. It was found that the massifs were formed during the Early Jurassic (181 ± 2 Ma) under the geodynamic conditions of the active continental margin. The initial magma of these granitoids originated from a mixed source consisting of the Early Precambrian lower crust and the mantle. There is a reason to believe that the granitoids of the Uda complex in the Chogar block constitute the southwestern edge of the Uda–Murgal magmatic arc formed under subduction, which extends along the border of the Paleo-Asian Ocean and the Siberian continent.