Climate Change Since Late Plesitocene In China-Mongolia Border Region, Dong Ujimqin Qi, Inner Mongolia

Along the China-Mongolia border in Dong Ujimqin Qi of Inner Mongolian, Neozoic strata developed. A study on Neozoic paleoclimate and environment of the Inner Mongolia will contribute to filling up the research blank and to providing fundamental information for studying the change regularity of the climate and environment in Inner Mongolia plateau.Based on the previous research achievements, via Luoyang shovel construction at each level of the tableland and analysing and testing the grain size, together with the OSL Age Determination Test to each lacustrine tableland, and finally through analysis and identification on sporopollen in the deposits in the boreholes and indoor environment comparison, the climate and environment evolution in Zhun'e-Ren Concave Field from late of the Late Pleistocene epoch till now can be divided into 4 stages as follows.:1. Late of the Late Pleistocene epoch (21ka) represents tableland T4: Pinus dominates coniferous forest, while the herbaceous plants is fewer. It is cool and rather arid. Medium sand and fine sand occupies a significant part in this tableland, also it is charactered with poor sorting and unstable hydrodynamic condition and can be classified as lake face sedimentary environment.2. The early Holocene (10.8ka) represents tableland T3: Vegetation types show a vast variety and it unfolds a landscape of mixed conifer-broadleaf forest and grassland. The climate starts to convert from cool and arid to cold and wet . The sediment of borehole is made up of medium sand and clay. The sorting inclines to be better from the bottom to the top. The sedimentary environment is turbulent and is classified as lake face.3. The early-Mid Holocene (8.6ka) represents tableland T2: Vegetation condition converts from a state dominated by coniferous forest to the one dominated by pine and spruce. The temperature rises a bit. There is significant fluctuation in temperature. Overall it is still relatively dry. The upper hole is eased drought. Sediments at the bottom of the borehole is mainly composed by medium sand and fine sand,while the upper sediment is dominated by silt and clay. Overall its sorting is poor. The sedimentary environment is unstable and should be classified as the lake face and alluvial lake face sedimentary environment. 4. The late Holocene (0.34ka) represents tableland T1:The vegetation unfolds a sight of mixed conifer-broadleaf forest and grassland. The temperature and humidity are increased. The climate converts from cool and rather dry to rather wet. Sediments at the bottom of the borehole are mainly fine sand and silt, while the upper part is dominated by medium sand and fine sand. The sorting at the top is much better than the one at bottom. The sedimentary environment is unstable. It is inferred as alluvial lake face sedimentary environment.We can distinguish the cold and arid stage in late of the Late Pleistocene epoch ; the stage in the early Holocene when the temperature rose again; the climate fluctuation stage in the early-Mid Holocene and,the cool and arid stage with active sand and wind in the late Holocene. It is almost consistent with the previous researches which reflects the paleoclimate characters from late of the Late Pleistocene epoch till present.