New Results of U/Pb Dating of Cretaceous Igneous Rocks of the Komsomolsk Ore District (Middle Amur River Area)

The Komsomolsk tin-ore district is located along the Miao-Chan Ridge in the Middle Amur River area (Khabarovsk krai) within the Badzhal accretionary terrane of the Sikhote-Alin orogenic belt. This work presents new results of U–Pb zircon dating of tonalite from the Miao-Chan complex of the Silinka granite pluton (99.7 ± 1.1 Ma) and rhyolites of the lower part of the Kholdami Formation (98.4 ± 1.0 and 98.7 ± 1.2 Ma) from the northeastern part of the Komsomolsk district. The geochemical characteristics of the rocks studied show that granitoids of the Miao-Chan complex are I-type rocks and that synchronous rhyolites of the Kholdami Formation are highly aluminous and correspond to S-type rocks. New data on the composition and early Cenomanian age of the rocks make it possible to consider the ore-magmatic system of the Komsomolsk ore district as part of the previously identified Albian–Cenomanian igneous province of Pacific Asia.