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

Abstract

ABSTRACTThe local last glacial maximum (LGML) 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 (LGMG). 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 LGMG temperature depression inferred from regional climatic proxy data. Combined with other proxy data, this suggests that the LGML glacial advance in Dalijia Shan resulted from lower temperatures and slightly reduced precipitation compared with present, whereas the LGMG advance was more restricted because much colder conditions were combined with much lower precipitation.