Thermo-tectonic evolution of the northern Erlian Basin (NE China): Evidence from fission track and (U-Th)/He thermochronology

In this study, we present new apatite fission track (AFT) and (U-Th)/He ages to reconstruct the thermal history of the Uliastai Sag in the northern Erlian Basin. The analysis of 17 sandstone samples from six boreholes shows that AFT ages are primarily concentrated in the range of 30-90 Ma, apatite (U-Th)/He ages range from 2 to 30 Ma, and zircon (U-Th)/He ages range from 40 to 160 Ma. The time-temperature paths demonstrate that the Uliastai Sag experienced rapid subsidence and heating in the Early Cretaceous, a cooling/exhumation process in the Late Cretaceous, and remained stable during the Cenozoic. The thermo-tectonic evolution of the basin was strongly influenced by the re-orientation, trench-retreat subduction, and transformation of the Izanagi Plate to the Pacific Plate. The re-orientation and trench-retreat subduction of the Izanagi Plate during the late Early Cretaceous led to rapid exhumation/cooling during the Late Cretaceous (110-65 Ma). Since -80 Ma, the young and buoyant Izanagi Plate has caused temporary stagnation of tectonic activities and a long stratigraphic hiatus in the Cenozoic. The reheating event, which has been occurring since -15 Ma, is the result of rising heat flow due to the closure of the Japan Sea. The Uliastai Sag experienced two heat flow peaks of -100 mW/m2 and -85 mW/ m2 during the Early Cretaceous and the Neogene-Quaternary, respectively. These findings suggest that the tectonic evolution and regional volcanic activities of the Erlian Basin may be attributed to complex mantle dynamics.