Compositions of δ18O and δ13C in various carbonates of core RM in the Zoigê Basin and climatic significance

The hole RM, the deepest one fully obtained core in the Qinghai-Xizang Plateau, situated in the depositional center of the Zoige Basin (33°57′N; 102° 21′E) in the northeastern Qinghai-Xizang Plateau with a depth of 310.46 m. From ¹⁴C dating and paleomagnetic stratigraphic study, the core RM can date back to 900 ka B.P.. In this paper we analyzed the compositions of δ¹⁸O and δ¹³C in various carbonates can date (snail, obstrode, chemical carbonate) in core RM and discussed preferably the paleoclimatic record by the proxies of δ¹⁸O and δ¹³C of chemical carbonate (authicarbonate) from core RM in the past 140 ka. The results showed that the values of δ¹⁸O in various carbonates are generally identical, and the values of δ¹³C in it are inconsistent, while there exist better relativity. The studies also demonstrated that there was a negative correlation between δ¹⁸O and δ¹³C of authicarbonate in core RM in the past 140 ka, showing that the changes of δ¹⁸O values were mainly relative to the water temperature. According to above, the climatic evolutionary sequence were rebuilt in the past 140 ka in the region.