青藏高原RM孔自生碳酸盐稳定同位素组成及其古气候  

COMPOSITIONS OF 18 O AND 13 C IN VARIOUS CARBONATES AND THE SIGNIFICANCE OF CORE RM IN THE ZOIE BASIN

作　　者：吴敬禄[1] 

机构地区：[1]中国科学院南京地理与湖泊研究所

出　　处：《地理科学》1997年第1期18-23,共6页Scientia Geographica Sinica

摘　　要：对ＲＭ孔不同成因碳酸盐（腹足类、介形类，化学成因碳酸盐）同位素进行比较研究，并利用自生碳酸盐碳、氧同位素代用指标，对该区近０．１４Ｍａ来的古气候演化进行初步讨论。研究表明：不同成因的湖泊碳酸盐其氧同位素值基本接近，碳同位素差值较大，但相关性较好；该区近０．１４Ｍａ来自生碳酸盐碳、氧同位素呈反相关关系，表明氧同位素值波动主要受温度控制，即氧同位素高值段对应气候暖期，并据此重建了该区０．１４Ｍａ来气候演化过程。The hole RM, the deepest one fully obtained from the core in the Tibetan Plateau, is situated in the depocenter of the Zoie Basin(33°57′N; 102°21′E) in northeastern Tibetan Plateau with a depth of 310.46 m. From 14 C dating and paleomagnetic stratigraphic study, the core RM dated back to 900 ka B.P.. In this paper we analyzed the compositions of 18 O and 13 [KG*3/4]C in various carbonates (snail, obstrode, chemical carbonate) in core RM and discussed preferably the paleoclimatic record by the proxies of δ 18 O and δ 13 C of chemical carbonate (authicarbonate) from core RM in the past 140 ka.. The results show that the values of δ 18 O in various carbonates are generally identical, and the values of δ 13 C in it are inconsistent while there exists a better relativity. The studies also demonstrate that there is a negative correlation between δ 18 O and δ 13 C of authicarbonate in core RM in the past 140 ka, showing that the changes of δ 18 O values is mainly relative to the water temperature. According to the above, the climatic evolutionary sequence in the past 140 ka in the region is rebuilt.

关 键 词：若尔盖盆地 碳酸盐 稳定同位素 古气候 青藏高原 

分 类 号：P532[天文地球—古生物学与地层学] P578.6[天文地球—地质学]