LATE HERCYNIAN-EARLY INDOSINIAN MAGMATIC CYCLES IN MEIHEKOUKAIYUAN BETWEEN JILIN AND LIAONING PROVINCES: Tectonic Implication

Six high precision zircon dating data and two inherited zircon ages for the Late Hercynian-Early Indosinian granitoid in this area are obtained. Its formation ages are confirmed as 305-242 Ma, which can be assigned into the Early-Middle Triassic rock unit, Late Permian rock unit and Middle Permian rock unit, respectively. The age of Xiaosiping pluton and the fact that this pluton is covered unconformably by the Late Triassic strata indicate that the Paleo-Asian oceanic tectonic domain was completed between 242 and 228 Ma. Based on the above rock ages, as well as its tectonic settings and the occurrence of the adjacent molasse facies layer, it is revealed that the Late Hercynian-Early Indosinian tectonic movement or tectonomagmatic cycle of the Paleo-Jihei orogenic belt experienced a multi-episode progressive evolution, and was constrained by the Phanerozoic Pangea cycle.