Stable isotopes of modern herbivore tooth enamel in the Tibetan Plateau: Implications for paleoelevation reconstructions  

作　　者：XU Qiang DING Lin ZHANG LiYun YANG Di CAI FuLong LAI QingZhou LIU Jing SHI RenDeng 

机构地区：[1]Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Science Bulletin》2010年第1期45-54,共10页

基　　金：supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KZCX2-YW-Q09-03);National Natural Science Foundation for Distinguished Young Scholar (Grant No. 40625008);National Basic Research Program of China (Grant No. 2009CB421000)

摘　　要：Fossil tooth enamel from herbivores is considered one of the best proxies for paleoclimate and paleoelevation reconstructions, due to its low susceptibility to diagenetic alteration. A synthesis of oxygen and carbon isotope analyses of modern tooth enamel from herbivores such as Tibetan yaks, asses and antelopes is assessed. The average δ 13C(PDB) value of herbivore tooth enamel in the Lhasa and south Qiangtang terrains is-11.3‰± 1.1‰, whereas in the north Qiangtang and Hoh Xil terrains value is-10.2‰± 1.4‰ consistent with the current C3-dominant ecotype in the Tibetan Plateau. In addition, the average δ18O(PDB) values from tooth enamel show a northward systematic increase from-11.8‰± 3.4‰ in the Gyirong Basin, to-11.1‰± 1.1‰ in the Lhasa and southern Qiangtang terrains, and then to-9.0‰± 1.1‰ in the northern Qiangtang and the Hoh Xil areas, similar to those of the local river water and precipitation variation trends. It is suggested that δ 18O(PDB) values of tooth enamel should not be used directly to evaluate the paleo-elevation of the Tibetan Plateau, because oxygen isotopic composition from tooth enamel is a com-bination of drinking water (precipitation-and river-sourced) and diet (plant-sourced). Moreover, an empirical relationship between oxygen isotope of tooth enamel and modern river water, and as well as elevation is recommended, which can be used in future studies of Tibetan Plateau paleoelevation.Fossil tooth enamel from herbivores is considered one of the best proxies for paleoclimate and paleoelevation reconstructions, due to its low susceptibility to diagenetic alteration. A synthesis of oxygen and carbon isotope analyses of modern tooth enamel from herbivores such as Tibetan yaks, asses and antelopes is assessed. The average δ^13C（PDB） value of herbivore tooth enamel in the Lhasa and south Qiangtang terrains is -11.3‰ ＋ 1.1‰, whereas in the north Qiangtang and Hob Xil terrains value is -10.2‰ ＋ 1.4‰ consistent with the current C3-dominant ecotype in the Tibetan Plateau. In addition, the average δ^18O（PDB） values from tooth enamel show a northward systematic increase from -11.8‰± 3.4‰in the Gyirong Basin, to -11.1‰ ±1.1‰ in the Lhasa and southern Qiangtang terrains, and then to -9.0‰ ±1.1‰ in the northern Qiangtang and the Hoh Xil areas, similar to those of the local river water and precipitation variation trends. It is suggested that δ^18SO（PDB） values of tooth enamel should not be used directly to evaluate the paleo-elevation of the Tibetan Plateau, because oxygen isotopic composition from tooth enamel is a combination of drinking water （precipitation- and river-sourced） and diet （plant-sourced）. Moreover, an empirical relationship between oxygen isotope of tooth enamel and modern river water, and as well as elevation is recommended, which can be used in future studies of Tibetan Plateau paleoelevation.

关 键 词：稳定同位素 草食动物 青藏高原 珐琅质 牙齿 可可西里地区 碳同位素分析 氧同位素组成 

分 类 号：P597.2[天文地球—地球化学] S816.79[天文地球—地质学]