Cosmogenic 10Be surface exposure dating of ‘Little Ice Age’ glacial events in the Mount Jaggang area, central Tibet

Abstract

The timing and extent of ‘Little Ice Age’ (LIA) glacial advances on the Tibetan Plateau (TP) are critical for understanding climate during the past millennium. However, the lack of LIA chronologies in central Tibet makes it difficult to fully understand the nature of LIA throughout the TP. In this study, two presumed LIA moraines in the east of Mount Jaggang, Xainza range, the central TP, were examined and dated using 10Be surface exposure dating. Eight boulders from the two moraines yielded apparent 10Be exposure-ages ranging from 41 ± 31 to 529 ± 130 years. These 10Be exposure-ages indicate that glaciers advanced at least once in the Mount Jaggang area during the LIA. A relatively extensive glacial advance occurred around 267 ± 36 years, a relatively humid period as indicated by proxy data from lake sediments in the central TP. A glacial standstill might have occurred around 151 ± 36 years. The two LIA glacial events are comparable with those across the TP. However, much more efforts should be made on dating of LIA moraines in the Mount Jaggang area to elucidate the relationships between glacial advances and climate changes during the LIA.