Recent Progress in the Study of Paleo-permafrost and Paleo-environments in the Inner Mongolia Region and Northeast China
YANG Si-zhong1,JIN Hui-jun1,GUO Dong-xin1,L Lan-zhi1,CHANG Xiao-li1,HE Rui-xia1,YU Shao-peng1,SUN Guang-you2,ZHANG Qiu-liang3,ZHOU Mei3 (1. State Key Laboratory of Frozen Soils Engineering,CAREERI,CAS,Lanzhou Gansu 730000,China; 2. Northeastern Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun Jilin 130032,China; 3. Inner Mongolia Agricultural University,Hohhot Inner Mongolia 010019,China)
In the north of China,there are relics of ice-wedge casts and sand wedges far back in the Late Pleistocene. These periglacial relics,associated with paleo-permafrost in some areas and some phenomena resulted from the glacial-interglacial climate fluctuations,may be explained by desertification or dune-fixation in the arid regions. Under such circumstances,the paleoclimatic proxies in different regions can be cross-examined and use to reconstruct the paleo-climatic and environmental changes and advance-retreat of the southern limit of permafrost. Therefore,a fieldwork was carried out from May to July,2008 to investigate the periglacial relics and paleosols in Erdos in Inner Mongolia,Huanggangliang Mountains,Xiao Hinggan Mountains,Songnen Sandland and Sanjiang Plain in Northeastern China. Newly exposed sandy and soil wedges were investigated in Erdos and Datong regions,respectively. A observation transect consisting of eight boreholes and two automatic stations was established in the China Ecological Research Networks Station at Genhe in the middle part of the Da Hinggan Mountains to study the relationship among permafrost,forested wetlands (muskegs) and snow cover,and the effects of terrestrial processes on permafrost. In the Huanggangliang Mountains,involutions were found and sampled for reconstructing the development of permafrost. In the Songnen Sandland,the development of paleo-sand dunes and paleosols were compared with the advances and retreats of permafrost in other parts. In the Xiao Hinggan Mountains,the degradation of permafrost and the shrinkage of sporadic permafrost were significant. Surface coverage changes due to agriculture development result in rising permafrost temperature and decreasing permafrost table,or disappearance of shallow permafrost. Integration and comparation of the preliminary results might give useful clues of the changes of southern limit of permafrost and environment in Pleistocene and Holocene in northern China.
【Fund】： 中国科学院冰冻圈科学国家重点实验室开放基金项目(SKLCS07-04);; 国家自然科学基金项目(40901044;40701031)资助
【CateGory Index】： P642.14
【CateGory Index】： P642.14