A Late Quaternary Climate Record Based on Multi‐Proxies Analysis from the Jiaochang Loess Section in the Eastern Tibetan Plateau, China

Abstract

We compared the stable carbon isotopic records from a loess transect of the Jiaochang in the eastern Tibetan Plateau, spanning the last -21,000 years, with multiproxy data for pedogenesis, including magnetic susceptibility, clay fraction, Fedme, ratio, carbonate and total organic carbon content, in order to probe the mechanisms of dl'C values of organic matter and Late Quaternary climate variations in the eastern Tibetan Plateau. Our results indicate that there is no simple relationship between d 3 C of organic matter and summer monsoon variations. The change in 6°C values of organic matter (in accordance with the ratios of CS to C4 plants) results from the interaction among temperature, aridity and atmospheric p C 0 z level. Drier climate and lower atmospheric pCOz level contribute to positive carbon isotopic excursion, while negative carbon isotopic excursion is the result of lower temperature and increased atmospheric p C 0~ level. Additionally, our results imply that the Tibetan monsoon may play an important role in climate system in the eastern Tibet Plateau, which specifically reflects frequently changing climate in that area. The results provide new insights into the forcing mechanisms on both the d 3 C values of organic matter and the local climate system.

Late Cenozoic Geology and Paleo‐environment Change in the Eastern Edge of Qinghai‐Xizang Plateau

“…Since 1980's, there have been some hypotheses on paleoclimatology that considered that the uplift of the Qinghai-Xizang Plateau was the main cause contributing to the Eastern Asian and even global environmental changes in Cenozoic (Raymo and Ruddiman, 1980;Ruddiman et al, 1989). The influence of the Qinghai-Xizang Plateau on global changes had been made by several ways including such as its altering to the atmosphere and marine sediment as well as its shielding effects to vapor; it was proved through investigation that the environment change effect on the uplifting of the Plateau was an important method further to understand the mechanics that the influence of the Qinghai-Xizang Plateau to the environmental change (Li and Fang, 1998;Bai et al, 2007;Zhou et al, 2007). In order to understand the relationship between monsoon environment and the Plateau uplifting in China, it should be made contrast and investigation on environment record in different areas to realize.…”