Wudu Region Since The Pleistocene Environmental Evolution In A Preliminary Study

Wudu is an important and sensitive region because of its special location. It is located in the northeastern fringe of Qinghai-Xizang Plateau and the demarcation line of south and north of China. Meanwhile, it is also one of the four regions where the debris flow happens frequently. Therefore, many of the researches have been done in this region. On the basis of field investigation and material collection, some data have been obtained. Several advanced software such as Grapher, Origin, Photoshop, Freehand, and SPSS were introduced in this paper to analyze these data and draw some figures.The deposition of Wudu Loess indicated that the ntmosphere circulation around the Qinghai-Xizang Plateau has changed greatly since the middle Pleistocene. It is closely related with the MPR (Middle-Pleistocene Revolution), which is partly originated by the uplift of Qinghai-Xizang Plateau. The north branch of the west wind gets stronger and the dust blown from the desert in the north of China can clime over the Qinling Mountain. Meanwhile, the grain size of bess in Wudu also indicates that these dusts partly originate from the Qinghai-Xizang Plateau. It means the height of Qinghai-Xizang Plateau was over 3000m, which can lead to the periglacial in the plateau. Furthermore, this paper also seeks to establish the environment change sequence of this region through the analysis of the bess profile and a comparison with the curve of MIS (Marine Isotope Stage) V28-239.Several debris-flow profiles were displayed in this paper. After discussing the reliability of debris-flow records, we divide three period when the debris-flow happened dramatically, they are 7000-6000aB.P, 4000aB.P, 2000aB.P, respectively. Some suggestions are given to prevent the hazard of debris-flow on the basis of the discussion on one of the important elements, the geological background of the region, which stimulate the happening of debris-flow.The Little Ice Age is one of the focuses in the study of climate changes during the Hobocene. From the historical files recorded by the ancient people,the climate changes data span nearly 500 years In Wudu area were collected．By using software such as Origin,Grapher etc,we can bud thatthe climate In Wudu region has demonstrated a tendencyic becomehumld duringthepast500years．Butan opposite direction was observed at the beginning of＊theing last century． Due to various reasons,this paperjust gives a primary research on environment changes Inwudu region from Middle－Plelstocene．Some detailed environment change events and reasons,the correlation betweenthe accumulation ofwudu loess and the uplifting of Qinghal－Xlzang Plateau,the correlatlonbetweenthe accumulation of Wudu loess and the change of east Asia monsoon,are not discussed deeply enough．More cllmateproxles and accurate data are expectic employedlnthefuture study．...