DEFORMATION HISTORY OF THE SONGLIAO BASIN IN CONTEXT OF LATE CRETACEOUS- PALEOGENE (SYN-LARAMIDE OROGENY PERIOD) TECTONICS OF THE NORTHEAST ASIA: INSIGHT FROM REGIONAL ANGULAR UNCONFORMITIES AND LOW TEMPERATURE THERMOCHRONOLOGY

Defromation and orogenic history the long-lived Cretaceous Songliao Basin in the eastern Asia is comparable with Laramide Orogeny on the northern American plate, in order to understand the geodynamic process of the planet earth. This study shows the results obtained from an integrated study (geology, geophysics, geochronology) carried out on the sedimentary deposits in Creataceous Songliao Basin in order to define the timing and magnitude of the multi-episodic tectonic inversion during post-rift stage. Based on fission track analysis and modeling of 32 samples from basin-wide together with other geological dates, at least four episodes of inversion are distinguished in the studied area: I, the beginning episode of post-rift inversion is proposed at the end of Qingshankou Fm(T11 Unconformity, 88.5Ma), which is 15 Ma earlier than former achievement about inversion timing (the end of Nenjiang Fm, T03 Unconformity, 73Ma); II, an locally inversion episode at the end of 2st Member of Nenjiang Fm(T06 Unconformity, 77Ma), which mainly occurred in east part of the basin; III, an enhanced inversion episode of the whole basin range, at the end of Nenjiang Fm (T03 Unconformity, 73Ma), IV, the maximal inversion episode at the end of Cretaceous (T02 Unconformity, 65Ma). The magnitude of above inversion episodes is gradually increasing from I to IV, with it more intensely in east than in west for each episode. Both timing and pattern of episodic inversion are consistent with paleo-pacific plate motions relative to Eurasian plate. Thus, the episodic post-rift inversion of Songliao Basin may be caused by the pulsating subduction of Pacific plate underbeneath Eurasian plate.