The Luochuan Last Glacial Vegetation, Wave Characteristics And Their Response To Climate Change

Chinese climate is characterized as the seasonal alternation between summer monsoon and winter monsoon. In addition, the section record of loess-ancient soil, has left behind a excellent, long-term, alternative record for such alternation. So Loess has been among top 3 pillars in the fourth ancient circumstances , which is as important as Deep Sea Sediment and Polar Ice-Core. The section of loess selected in this research is the Luochuan section which possess better continuity and higher-resolution. Up till now ,deep research has been made on the section, however, most of which is emphasized particularly on physical and chemical index of the earth, to the contrary, as for the biological index of the earth ,has always been the weak tache, pollen, comparatively lesser. In that regard , we therefore look on the analysis of pollen as means by which ancient vegetation and ancient climate are renewed, and obtain the pollen information of high-resolution by encrypted sampling , test the date by means of thermo-luminescence, further probe into the characteristics of vegetation fluctuation as well as consequent impact on climate during the period of the Last Glacial in the Luochuan.The process of vegetation evolvement, which was exactly embodied in the Malan loess section in the Luochuan during the period of the Last Glacial is divided into three phrases, i.e. P1,P2 and P3, accordingly in accordance to MIS2, MIS3 å'Œ MIS4 phrase. Among the pollen combination of the whole section, the herbage plant is in the dominant place, which shows the fact that plain vegetation has come into being during the last glacial in this end , moreover is precisely in line with the style of vegetation reflected by pollen sequence in other areas in our country. Of course , the vegetation of the contemporaneity is not quite the same in different areas ,which resulted from then discrepancy of microclimate and physical geographical condition. After deep analysis it is agreed that the characteristics of climate in this area have been cold and dry in the former and later term since the the Last Glacial. The former term , climate was relatively steady without large change , the later term , fluctuating ,and the medium term, comparatively agreeing , warm cooling and half-moisture along with a serial fluctuation ,which was composed of twice obvious warm terms, i.e. MIS3a and MIS3c. and one obvious cold term ,i.e.MIS3b. and in the MIS3a term , the climate is more warm and moisture, but is different from the event of high temperature and heavily raining in the Qingzhang altiplano , it shows the...