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干旱区地理 ›› 1999, Vol. 22 ›› Issue (3): 82-88.doi: 10.13826/j.cnki.cn65-1103/x.1999.03.014

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新疆天山小尤尔都斯盆地全新世孢粉植物群与环境演变

许英勤   

  1. 中国科学院新疆生态与地理研究所, 乌鲁木齐 830011
  • 收稿日期:1999-03-16 发布日期:2025-12-19

THE SPORO-POLLEN PLANT COMMUNITIES IN THE HOLOCENE IN THE SMALL YOURDUSI BASIN, TIANSHAN MOUNTAINS,XINJIANG

Xu Yingqin   

  1. Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
  • Received:1999-03-16 Online:2025-12-19

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 2700~2900m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。

关键词: 孢粉, 植物群, 环境演变, 尤尔都斯盆地

Abstract: 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 2500~2700m a.s.l.,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 following 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 14C 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 2700~2900m a.s.l.
(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.

Key words: spore-pollen, vegetation community, environmental evolution, Yourdusi basin.

中图分类号: 

  • P95