Pollen Assemblages Of Tamarix Cone And Environmental Change In Andier Ancient City Region During The Recent About 200 Years

Under the trend of global warming, different regions have different response patterns. Arid desert is a product of arid climate, to the sensitive nature of the underlying surface, it first responds to the global climate change,then in response to the process of the special environment of the desert climate’s feedback.Taklimakan Desert is China’s largest flow desert, due to the impact of weather activities such as extreme drought and strong sandstorm, the ecological environment there is extremely bad. The southern region of Taklimakan Desert(hereinafter referred to as Tarnum area) is one of the most serious desertification and regions of the world, which is the most sensitive to global climate change. For a long time, due to the lack of traditional information carries, high-resolution environmental change research is facing many difficulties when we study the changes of strong sandstorm activities in the desert region. However, the appearance of Tamarix cone provides us a new research method and theoretical basis to solve the task about how to obtain the information of the environmental changes in arid areas. As the "annual layers", the sedimentary veins of Tamarix cone not only have the effect of dating significance, but also contain the rich paleo-environmental information.Andier ancient city is located in Minfeng, it is a representative area in the southern region of Taklimakan Desert. From the geographical location, it locates in the area which is sensitive to the global environmental change of climate. Tell from the vegetation, it is located in the desert and oasis transition zone. Andier ancient city is an ideal place to study the evolution of climate change and vegetation. This article attempts to establish pollen combination of high-resolution sequence since 1792, through the Andier ancient city pollen analysis that deposited in Tamarix cone sedimentary veins. We reconstruct the process of temperature and precipitation change sequences since 1792 by using WAPLS method, and then restore the Andier ancient city paleo-environmental evolution to reflect the area climatic and environmental changes. The main conclusions of this paper are :(1) The vegetation in Andier ancient city region has succeeded from the desert-shrub to the desert-grass, then to the desert-shrub vegetation since 1792.(2) The process of climate change in Andier ancient city region can be divided into 3 stages: from 1792 to 1905, the climate is warm and dry. During the period from 1905 to 1950, the climate is cold and wet. After 1950, the climate is warm and wet.(3) Before the 20 th century, dry and wet changes of climate in this region are mainly attributed to the westerlies’ southward and intensity increases. After the 20 th century, the climate becomes warm and wet, it is linked to the increasing level of water vapor of outside environment, and the inland arid areas is associated with increased melting glaciers and runoff because of global warming.(4) Pollen assemblages can not only reflect the vegetation changes under the influence of the natural environment,but also can reflect changes in vegetation under different intensities of the impact of human activities. The pollen assemblages from the Andier ancient city indicates that a certain percentage of the crop pollen appeared nearly 200 years, indicating human activities have some impact on the environment changes.