甘肃疏勒河冲积扇绿洲全新世孢粉组合和环境演化

Pollen Assemblages and Environment Evolution in Shule River Alluvial Fan Oasis of Gansu

通过甘肃疏勒河冲积扇九道沟下游剖面(JDG)沉积物系统的孢粉分析,探讨了这一极干旱区全新世植被和气候环境演化。约4.3m厚沉积剖面的孢粉组合特征清楚地反映了研究区全新世植被经历了6个发展演替阶段,从老而新依次为:针叶林为主的针阔混交林—灌丛草原;灌丛草原;疏林灌木草原;针叶树为主的针阔混交林—灌丛草原;草原植被;针叶林—灌木草原。与植被发展演替相对应的气候环境经历了凉较湿→温干→暖湿→温较湿→温干→凉较湿的变化。这些结果对于了解该地区全新世气候演化以及中国西北干旱区未来环境预测方面都具有重要意义。

Based on a systematic analysis of spore-pollen in sediments from the Holocene profile at Jiudaoguo （JDG） in the Shule River Alluvial Fan Oasis, Gansu Province, this paper discusses the climate and environment changes of this region during Holocene. The features of pollen assemblages from the bottom to the top of the section clearly show that the vegetation has experienced six developing stages since 12 kaB. P. or so, i.e., coniferous-broad-leaf mixed forest and grassland, brush grassland, sparse woods and shrub grassland, coniferous forest dominated by conifierous-broad-leaf forest-shrub grassland, grassland and coniferous forest-shrub grassland. The paleoenvironment corresponding to the paleovegetation has probably undergone the cool and comparatively moist period, the temperate and arid period, the warm moist period, the temperate and comparatively moist period, the temperate and arid period and the cool and relatively moist period. These results provide valuable information for understanding the details of climate changes and environmental evaluation in the arid area of Northwest China in Holocene.