STABLE ISOTOPIC EVIDENCE FOR CLIMATE AND BASIN EVOLUTION OF THE LATE CRETACEOUS SONGLIAO BASIN, CHINA

The Songliao basin of northeastern China is among the largest sedimentary basins in China, and preserves a record of persistent nonmarine sedimentation that spans from the mid-Jurassic through the Cretaceous. The recent “Cretaceous Continental Scientific Drilling Program of China” has yielded nearly 2.5 km of continuous core from the Upper Cretaceous portion of this sedimentary record, and provides the opportunity to construct a record of terrestrial climate from this extraordinary archive that has been well-dated through a combination of paleomagnetic and radiogenic techniques. In this study we present oxygen and carbon results from 334 samples of ostracods recovered from the core, as well as strontium isotope and trace element data from a subset of these samples. Oxygen and carbon isotopes preserve a rich record with strong links to global climate, and robust response to ocean anoxic events as well as longer-term climatic trends. The sedimentary record and strontium isotopic data show that regional hydrologic changes also influenced the evolution of Songliao Basin. Particularly, the influence of a fluvial system that likely drained much of northwestern China changed through time. These results emphasize the complex interaction between global climate and regional hydrology in terrestrial archives.