Late Holocene glacier variations indicated by the δ18O of ice core enclosed gaseous oxygen in the central Tibetan Plateau

The delta O-18 of ice core enclosed gaseous oxygen (delta O-18(bub)) has been widely used for climate reconstruction in polar regions. Yet, less is known about its climatic implication in the mountainous glaciers as the lack of continuous record. Here, we present a long-term, continuous delta O-18(bub) record from the Tanggula glacier in the central Tibetan Plateau (TP). Based on comparisons of its variation with regional climate and glacier changes, we found that there was a good correlation between the variation of the delta O-18(bub) in this alpine ice core and the accumulation and melting of this glacier. The more developed the firn layer on glacier surface, the more positive the delta O-18(bub). Conversely, the more intense the glacier melting, the more negative the delta O-18(bub). Combined with the chronology of ice core enclosed gases, the glacier variations since the late Holocene in the central TP were reconstructed. The result showed that there were four accumulation and three deficit periods of glaciers in this region. The strongest glacier accumulation period was 1610-300 B.C., which corresponds to the Neoglaciation. The most significant melting period was the last 100 years, which corresponds to the recent global warming. The Medieval Warm Period was relatively significant in the central TP. However, during the Little Ice Age, there was no significant glacier accumulation in the central TP, and even short deficit events occurred. Comparisons of the late Holocene glacier variation in the central TP with glacier and climate variations in the TP and the Northern Hemisphere showed that it was closely related to the North Atlantic Oscillation.