Application of multiple dating techniques to the Holocene sediments of Angrenjin Co in the southern Tibetan Plateau

Abstract

The production of high-resolution and accurate age models for lake sediments in the Tibetan Plateau (TP) is a prerequisite for subsequent paleoclimatic studies. However, Holocene lake sedimentary records with high-quality age controls from the TP are extremely scarce. Here we present the results of a comparative study of the results of the application of multiple dating techniques (14C, 210Pb, 137Cs) and a paleomagnetic secular variation (PSV) study of the sediments of Angrenjin Co in the southern central TP, during the last 3600 years. The PSV data are verified by comparison with a stacked PSV record from East Asia and with a global geomagnetic field model. The results of 14C-dating, validated by independent 210Pb, 137Cs and PSV dating, together with Bacon age modeling, indicate that the reservoir has an age range of ~2287 ± 58–6434 ± 165 years; in addition, the median offset ages estimated by the Bacon age-depth model range from ~1330 ± 428 to 3102 ± 513 years. This cross-dating approach effectively reduces dating uncertainties for lake sediments in the TP, and it can accommodate a variable reservoir effect. Comparison of the paleomagnetic inclination record from Angrenjin Co with previously published records from Tangra Yumco, Taro Co and Nam Co indicates an overall high degree of similarity, suggesting that the paleomagnetic data from different lakes in the TP are reproducible. In addition, the similar inclination patterns across this large region indicate a common geomagnetic origin.