ABSTRACT
The Cretaceous represents one of the warmest periods in earth's history with a series of major geological events. The marine Cretaceous has been well studied, but the non-marine Cretaceous is still poorly understood. Songliao Basin is the largest Cretaceous continental petroleum basin in China. Songke 1 well is the first core exploration well in Chinese mainland, which is dominated by Cretaceous continental strata. Through systematic geochemical analysis, the actual drilling data and sample analysis and detection data of the Songke 1 well and other relevant wells in the basin are obtained, which provide an important reference basis for re-understanding the sedimentary environment and evolution of Songliao Basin. In this study, the oxygen isotope data are used to construct the high-resolution oxygen stable isotope evolution profile of middle-shallow layers in Songliao Basin, which enrich the stable isotope geochemical data in Northeast China. The comparison of oxygen isotope results show that the significant warming events in the sedimentary period of Qingshankou formation are highly consistent with the global paleomarine extreme greenhouse climate time window in the early Late Cretaceous, which is characterized by the temporal and spatial response of land and marine environment to paleoclimate abrupt events.
