| Abstract: | The Late Quaternary glaciation of Tibet has received considerable attention in the last few decades due to its influence on the regional climate, especially the Asian summer monsoon. Recently, however, it has been argued that the Tibetan ice sheet also might have played an important role in initiating global-scale palaeoclimatic changes. Controversy, however, exists on the nature of Late Quaternary ice cover over Tibet due largely to the subjectivity in the interpretation of the sparse and complex geomorphological evidence. We have examined this problem in the light of δ 18O data (a temperature proxy) of ice cores-from the Dunde ice cap on the northern flank of Tibet. Considering only the gross features in the Dunde ice-core isotopic data, we have interpreted a temperature decrease of 4°–6°C and consequent lowering of equilibrium line altitude (ELA) in the range 700–850 m during the last glacial stage (LGS). This could have caused depression of the snow line below the mean altitutde of the Tibetan plateau, resulting in an areally extensive but marginally thick ice cover. However, if one also considers the possibility that precipitation on the Tibetan plateau during LGS may have been significantly lower than at present, the ELA depression would be much less than that estimated by considering the temperature effect alone. |
