Phytolith Deposition Distribution and Climate Inversion in Nanjishan Wetland of Poyang Lake
In order to reveal the sedimentary distribution characteristics of phytolith in Nanjishan wet-land and reverse the climate change process,the sedimentary column sample and 17 topsoil samples were collected,and the sedimentary core chronological sequence based on 210Pb radioactive element dating was established,and the phytoliths were extracted from the samples and their distribution characteristics of combination were analyzed in this paper.The results showed that a total of 19 phy-tolith types were identified.The main representative types in topsoil were fan type,square,rectan-gle,dumb bell of the warm types and point,smooth-elongate of the cold types,which accounted for 24.43％,11.21％,9.85％,6.95％,6.50％,8.82％,respectively.Columnar sediments were dated for 74 years,and the representative types in sedimentary column were Square,Rectan-gle,Fan type of the warm types and Trapezoid,Point,Smooth-elongate of the cold types,which accounted for 7.20％,10.41％,20.81％,7.69％,7.71％,8.62％,respectively.The average pro-portion of warm phytoliths was 66.19％and that of cold phytoliths was 31.65％.Combined with cli-mate temperature data,climate warmth index(Iw)and drought index(Iph)results showed that the temperature in Nanjishan has been increasing in the past 100 years,and the environment has experi-enced a change process from humid to dry and then to humid.The constructed deposited phytolith-climate factor conversion model of Nanjishan wetland showed that the climatic environment character-istics of Nanjishan Wetland during the past 100 years can be divided into three stages:the climatic environment was cool and humid from 1945-2003;the climatic environment was warm and arid from 2003-2012;the climatic environment was warm and humid from 2012-2018.
万方数据
维普
