A Tentatively Quantitative Paleoclimate Reconstruction Of The Dune Fields Of Northern China During The Last Glacial Maximum And Holocene Optimum

Dune fields of arid and semi-arid regions of Northern China, including Mu Us field, Otindag, Horqin, Songnen, Hulunbuir and parts of Badain Jaran and Tengger deserts, Loess Plateau (32-50°N,100-135°N), are situated at margin of the area dominated by East Asian Monsoon circulation, and the environment is quite sensitive to paleoclimate change. Many paleoclimatic reconstructions have been undertake in this region, typically form pollen, peat bog, loess paleosol sequence, lake sediments etc, and most of these records are in good chronology sequence.In this thesis, we collect and analyze the paleoclimate proxy data from more than300studies, datasets and relevant atlas. We find that, compared with the modern annual temperature and precipitation, the temperature decreased by5-11°N and the precipitation decreased by180-350mm during the Last Glacial Maximum (LGN,26-16ka); the temperature increased by1.0-3.5℃, and the precipitation increased by30-400mm in Mid-Holocene Optimum (HO,9-5ka). With the comparison to the numerical simulation results, we have discussed the mechanisms of the paleoclimate change in the LGM and HO.Our investigation shows that the paleoclimate records are not in complete consistency with the numerical simulation results; at the same time, more integrated and precise dated loess-paleosol sections have to be found, especially for the LGM in this monsoon marginal region; in addition, we need to pay more attention to the high precision paleoclimate numerical simulations with regional climate models in order to fully understand the past climate changes in dune fields in Northern China.