Zircon U-Pb age of granitoids in the Maizuru Belt, Southwest Japan and the southernmost Khanka Massif, Far East Russia

Abstract

The Maizuru Belt in southwest Japan and the Khanka Massif in Far East Russia include both Siluro-Devonian and Permo-Triassic granitoids. In order to elucidate the simultaneity of granitoid magmatism in the Maizuru Belt and the Khanka Massif, we investigated zircon U-Pb ages using LA-ICP-MS for granitoid samples from the Maizuru area in the northern zone of the Maizuru Belt and from the Vladivostok area in the southernmost part of the Khanka Massif. Five granitoid samples from the Vladivostok area yielded ages of 422.2±2.5 Ma, 260.7±3.1 Ma, 301.7±2.4 Ma, 249.7±3.5 Ma, and 431.9±2.7 Ma. Additionally, a porphyry sample yielded an age of 423.7±3.2 Ma. Four granitoid samples from the Maizuru area yielded ages of 291.6±4.3 Ma, 443.8±4.1 Ma, 279.7±2.4 Ma, and 259.0±3.0 Ma. In reference to the coexistence of the Triassic sedimentary sequence and Siluro-Devonian and Permo-Triassic granitoids across the Sea of Japan, it seems that there were strong relationships between the northern zone of the Maizuru Belt and the southernmost part of the Khanka Massif. Our data provide additional evidence to support a geological connection between southwest Japan and the Vladivostok area before the Miocene opening of the Sea of Japan.