Timing and evolution of Mesozoic volcanism in the central Great Xing'an Range, northeastern China

In this paper, we report on LA-ICP-MS zircon U-Pb dates of 14 Mesozoic volcanic rocks from the central Great Xing'an Range (CGXR). These data are integrated with the temporal and spatial distribution of local magmatism-related Mesozoic mineralization, in an effort to develop an understanding of the geodynamic evolution of the region. Periodic magmatic events in the GXR date from similar to 1,703 through similar to 145 Ma. Mesozoic volcanism in the CGXR can be subdivided into three episodes: Triassic (250-205 Ma), Early-Middle Jurassic (182-165 Ma), and Late Jurassic-Early Cretaceous (155-115 Ma). A revision of the previously defined volcanic sequence is offered using a combination of our zircon U-Pb ages and published Mesozoic geological and geophysical evidence from northeast China. We propose that (a) Early-Middle Triassic volcanism in the CGXR resulted from subduction of the Paleo-Asian oceanic plate; (b) Late Triassic volcanism was related to subduction of the Mongol-Okhotsk oceanic plate (especially near the Erguna Block) and subsequent extension after the closure of the Paleo-Asian Ocean; (c) Early-Middle Jurassic volcanism was mainly controlled by the southward subduction of the Mongol-Okhotsk oceanic plate; (d) Late Jurassic-initial Early Cretaceous magmatism was initiated by closure of the Mongol-Okhotsk Ocean; and (e) late Early Cretaceous volcanism was induced following the final closure of the Mongol-Okhotsk Ocean and rollback of the Paleo-Pacific oceanic plate.