摘要:
根据乌鲁木齐河尾闾湖泊东道海子剖面的高精度孢粉分析,结合磁化率、烧失量和粒度分析资料,以剖面中含泥炭灰黑色粘土质粉砂层做的8个14C测年数据为基础,讨论了天山北麓古尔班通古特沙漠南部边缘的环境演变。研究认为:4500aB.P.以来该区域的植被是以荒漠为主的,但是1170B.C.以来,气候出现6次较大波动,1170～460B.C.,250～640A.D.和680～1645A.D.时段,气候相对冷湿,出现过荒漠草原,在这3个时段植物种类较多,覆盖度高,也是东道海子的高湖面时期,与气候的冷期对应;相反,在460B.C.～250A.D.,640～680A.D.和1645A.D.以来时段,属荒漠阶段,湖泊的水位相对下降,属中湖面期,与气候的暖期对应
Abstract:
High-precision polynological analysis was carried out on a section of the Dongdaohaizi Lake, a terminal lake of the rümqi river. On the basis of the data of the pollen analysis, the magnetic susceptibility, the loss on ignition, the grain size, and the 14C dating in the gray-black peat-bearing clayey silt layer, the evolution of environment in the south margin of Gurbantünggüt Desert was discussed. The results showed that desert vegetation was dominant in this area since 4 500aB.P. There were several climate fluctuations in this area since 1170B.C. During three periods (1170 ～ 460B.C., 250 ～ 640A.D. and 680 ～ 1645A.D.), climate was comparatively cold and humid and desert steppe prevailed over the area. There was preferable vegetation during this time intervals and the Dongdaohaizi Lake was at its high water level, corresponding to the cold periods. On the contrary, the periods of 460B.C. ～ 250A.D., and 640 ～ 680A.D. and 1645A.D. up to the present were dominated by desert vegetation, the water level was comparatively descended, corresponding to the warm climate periods.
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