The stable isotope record in cervid tooth enamel from Tantang Cave, Guangxi: Implications for the Quaternary East Asian monsoon

摘要

Studies have shown that stable isotope [oxygen (O) and carbon (C)] composition of mammal tooth enamel can provide information on a region's paleoclimate and paleoecology. Stable isotope analysis has been used to investigate the impact of the Qinghai-Tibetan Plateau uplift on the development and strength of the Asian monsoon. However, due to sparse data from southern China, a region dominated by the East Asian monsoon, O and C isotope analysis of mammal tooth enamel has been unable to fully inform on the impact of the monsoon environment in the region. Here, we present the results of the analysis of stable isotopes on a set of cervid tooth enamel from late Middle Pleistocene Tantang Cave in Bubing Basin, Guangxi, southern China and compare them with comparable isotope data from nearby early Early Pleistocene Mohui and middle Early Pleistocene Sanhe Caves. The results of the oxygen isotope analysis indicates that Tantang Cave (-8.70 parts per thousand to -6.39 parts per thousand) is similar to Mohui Cave (-8.71 parts per thousand to -6.34 parts per thousand), with both sites being more negative than Sanhe Cave (-4.77 parts per thousand to -1.20 parts per thousand). We suggest the East Asian summer monsoon was stronger during the Tantang and Mohui mammal occupations and weaker during the lifetime of the Sanhe mammals. This result is indirectly corroborated by vertebrate paleontological evidence. Murid rodents, implying an open grassland and somewhat drier climate, are found in great numbers in Sanhe. The carbon isotope results from Tantang (-17.70 parts per thousand to -10.26 parts per thousand), Mohui (-15.27 parts per thousand to -12.51 parts per thousand), and Sanhe (-16.63 parts per thousand to -14.71 parts per thousand) overlap extensively suggesting these various faunas primarily lived in a closed forest environment. The implications of these findings from stable isotope studies from Tantang are discussed in their broader context. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.