Pollen Assemblages and Environment Evolution in Shule River Alluvial Fan Oasis of Gansu
甘肃疏勒河冲积扇绿洲全新世孢粉组合和环境演化

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.