Geochronological and Paleomagnetic Constraints on the Lower Cretaceous Dalazi Formation from the Yanji Basin, NE China, and its Tectonic Implication

The Lower Cretaceous Dalazi Formation in the Yanji Basin, eastern Jilin Province is of particular interest because it contains key fresh water fossil taxa, oil and gas resources, a potential terrestrial Albian–Cenomanian boundary, regional unconformities. However, lack precise chronology for non-marine strata has precluded better understanding stratigraphic correlation processes. Here, we report magnetostratigraphic U–Pb geochronologic results sedimentary sequence from Xing’antun section Basin. Thirty-two zircons tuff sample were analyzed by secondary ion mass spectrometry (SIMS); zircon dating method yielded weighted mean 206Pb/238U age 105.7 ± 0.8 Ma (2σ, internal error). Paleomagnetic show that normal polarity, which was correlated to early chron C34n constrained SIMS data, further demonstrating upper late Albian age. established framework allows Basin other sequences northeastern China. similar geodynamic geologic background between rift basins China suggests unconformity Longjing formations may represent syn-rift post-rift stages thus switch extension contraction during mid-Cretaceous, precisely ~106–101 based on our new previously published high-precision lower Formation. It most likely attributable docking west Pacific plate along East Asian continental margin.