摘要
通过对小尤尔都斯盆地剖面孢粉植物群的分析研究，结合沉积物、粒度等沉积特征，探讨了小尤尔都斯盆地全新世以来的环境演化；研究表明：全新世以来，小尤尔都斯盆地气候较现在略为湿润，曾在盆地中分布的草甸草原植被现在则分布在海拔 ２ ７００～２ ９００ｍ的山地阴坡，四周山地向盆地一侧曾有较大面积的云杉林分布。
The Yourdusi basin is a high-elevated intermontane basin on the southern slope of the Tianshan Mountains, it is divided into large one and small one by a mountain, and the latter is located on the north side. The small Yourdusi basin is 2500 - 2700 m a. s. 1., its sedimentary material is mainly composed of alluvial, diluvial, fluvial and lacustrine deposits, and its marginal ring-shaped belt is covered by diluvial deposits. The annual temperature, the lowest one in January and the highest one in July are - 4. 8℃, - 46. 6℃ and 28℃, and the annual precipitation and evaporation are 264 and 1022 - 1247mm respectively. Swamp meadow and swamp vegetation distribute extensively. Based on analysis on the Holocene sporo-pollen samples, the evolution of the paleovegetation and paleoclimate is discussed in the paper. Through analyzing,. the fallowing conclusions can be obtained: (1 )Modern climate in the basin is dry and cold, and there are no forests in the surrounding mountains. Whereas the pollen content of China fir is as high as 27.8% in the surface deposits, which shows that the surface deposits are not the modern ones, and the spore-pollen composition of the upper zone IV represents a relative humid-cold climatic fluctuation in the late Holocene (about 1500 a B. P. ) through comparing it with that in the Bosten Lake section downstream, Altay Daluoba Section in north Xinjiang, and barkol Lake section in east Xinjiang; and the lower deposits formed in the early Holocene (about 9000 - 8000 a B. P. ) according to the environmental evolution sequence reflected by the data of ^(14)C dating, lithology, sedimentary speed and spore-pollen spectrum. (2) From a view point of the spore-pollen composition, climate in Holocen here was slightly humider than that at present, and the meadow grassland vegetation ever distributed in the basin grows on the sheltered-slope of the mountains of 2700-2900 m a. s. 1. (3) The pollen of the main plants in the community, wormwood artemisia and bryophyte, is difficult to distinguish under a microscope. (4)The high Pollen content of pine family in zone IV does not represent the underforestal deposits, and is possibly a surperposing result of wind and fluvial actions.
出处
《干旱区地理》
CSCD
北大核心
1999年第3期82-88,共7页
Arid Land Geography
关键词
孢粉植物群
环境演变
尤尔都斯盆地
全新世
天山
spore-pollen
vegetation community
environmental evolution
Yourdusi basin.
