Mid-MIS3 climate inferred from reconstructing the Dalijia Shan ice cap, north-eastern Tibetan Plateau.

ABSTRACT The local last glacial maximum (LGM_L) on Dalijia Shan occurred during mid-marine isotope stage 3 (MIS3), which is consistent with some Tibetan Plateau records, but asynchronous with the MIS2 global Last Glacial Maximum (LGM_G). Paleoclimatic reconstructions are key to advancing understanding such spatial and temporal patterns of paleoglaciation. Using multiple methods we reconstructed mid-MIS3 equilibrium-line altitude (ELA) on Dalijia Shan and inferred temperature depressions. Geomorphic ELA reconstructions combined with empirical data on current ELA temperature and precipitation yield a mid-MIS3 ELA of 4000 ± 78 m a.s.l. (618-851 m lower than current, and a temperature depression of 3.3-6.8 °C). Independent glacial modeling using the degree-day approach suggests a mid-MIS3 ELA between 3971 and 4024 m a.s.l. and a temperature depression of 4.2-5.6 °C. The consistency of these results indicate that mid-MIS3 temperature depressions in the Dalijia Shan region were 3.3-6.8 °C, which is less than the LGM_G temperature depression inferred from regional climatic proxy data. Combined with other proxy data, this suggests that the LGM_L glacial advance in Dalijia Shan resulted from lower temperatures and slightly reduced precipitation compared with present, whereas the LGM_G advance was more restricted because much colder conditions were combined with much lower precipitation. [ABSTRACT FROM AUTHOR]