The Baoji Jia Village, Tableland Holocene High-resolution Pollen Ancient Vegetation

As a cross-section and the latest chapter of the geological history, the environment evolvement of Holocene plays a role of the connecting link between the preceding and the following in the research of global change. As a information carriers of the research of global change, the loess in Chinese Loess Plateau is the most consecutive sediment and has the most abundance information since Quaternary. Based on the importance of Holocene and the Loess Plateau in the research of global environmental change, the combination of the two points -the environment evolution of Loess Plateau in Holocene has become the focus of many research scholars. With its unique characteristic, pollen and spore are favored by more and more scholars on the course of research of Environmental evolution. Therefore, we study the Holocene vegetation by distilling pollen and spore in the loess in Jiacun plateau of Baoji town in the Loess Plateau, which of significance speaks for itself.We passed geological survey in field and cheese the representative section i n Jiacun plateau of Baoji town. We gathered thick and fast 81 samples for pollen analysis in intervals of 2cm and 4 samples for TL in 1.9m thick of loess layer in Holocene. According as the date from authenticating pollen, we constructed respectively spectrums of the quality concentrations and the percentage.Known from the pollen diagram of the quality concentrations and the percentage, the pale-vegetation of the Jiacun section went though 5 biological stages of steppe, humid-grassland (sparse-wood-grassland), steppe (desert-grassland), humid-grassland, grassland.The date of pollen shows that the change of Mid-Holocene climate of Jiacun plateau of Baoji town is different from that of other plateaus in Loess Plateaus, and is different from conventional verdict that Mid-Holocene is a period of the warm moist time because of summer monsoon prevailing. However, it is comparable of the diagram and the result of pollen in the loess/desert transition zone or the Antarctic Vostok. The Mid-Holocene in the area includes three phase viz. early, center, later phases. In early of Mid-Holocene the climate was warm and moist, the intermediate stage climate is droughty, the later period was warm cool and inclined to droughty. This possibly is as a result of the special geographical position and the climatic conditions. This kind of climate evolution pattern possibly does not have the representation when...