江淮东部平原晚更新世末植被演替及气候变化

Vegetation Evolution and Climatic Change in the Eastern Plain of the Yangtze-Huai Rivers at the End of Late Pleistocene

在对位于江淮东部平原的江苏兴化蒋家舍地层剖面进行野外考察采样、AMS14C年代测定和孢粉分析的基础上,初步探讨了研究区晚更新世末的植被演替及气候变化。结果表明:1)27.9-13.5cal.ka BP,剖面中孢粉含量高,植物的科属也丰富。其中,27.9-26.7cal.ka BP、14.5-14.2cal.ka BP时段研究区植被为针阔叶混交林,反映气候温暖较湿润,而26.7-14.5cal.ka BP期间地层出现沉积间断,气候寒冷干燥;14.2-13.5cal.ka BP时段草本植物含量较高,总体为针阔叶混交林草原植被,气候温凉稍干。2)13.5-12.6cal.ka BP,剖面中孢粉含量较低,植物的科属也较贫乏,木本植物所占百分比较低,草本植物花粉含量相对较高。其中,13.5-12.8cal.ka BP为覆盖度趋低的针阔叶混交林或草原植被,气候向干冷发展,12.8-12.6cal.ka BP时段为针阔叶混交林植被,木本植物含量有所上升,反映气候稍暖湿。3)针叶乔木松属花粉和蕨类植物水蕨科植物孢子在剖面中自下而上均有不同程度的分布,常绿阔叶和落叶阔叶类出现率较低,这种现象跟当地现代植被的植物组合略有差异。

Based on the field investigation and sampling,AMS14C dating and pollen analysis of stratigraphic section in the Jiangjiashe site,Xinghua,Jiangsu Province,located in the eastern plain of the Yangtze-Huai Rivers,the vegetation evolution and the climate change in the eastern plain of the Yangtze-Huai Rivers at the end of late Pleistocene were discussed.The results showed that:1)During 27.9-13.5cal.ka BP,the sporopollen content in the profile was high,the families and genera of plants were also rich.Among this period,the vegetation of 27.9-26.7cal.ka BP and 14.5-14.2cal.ka BP were coniferous and broad-leaved mixed forest,reflecting warm and relatively humid climate.However,during 26.7-14.5cal.ka BP,there were sedimentary ceases and the climate was cold and dry.During 14.2-13.5cal.ka BP,the content of herb was higher.There were generally coniferous and broad-leaved mixed forest grassland vegetation,reflecting cool and slightly dry climate.2)During 13.5-12.6cal.ka BP,the pollen content of the profile was low with the poor family and genus of plants,and the percentage of woody plants was low with the relatively high pollen content of herb.During 13.5-12.8cal.ka BP,there were coniferous and broad-leaved mixed forest or grassland vegetation with low coverage,which reflected the climatic development towards dry and cold.During 12.8-12.6cal.ka BP,the content of woody plants increased and there were coniferous broad-leaved mixed forest vegetation,indicating that the climate was slightly warm and humid.3)The coniferous tree pollen of Pinus and the fern spores of Parkeriaceae were distributed in different degrees from bottom to top in the profile and the occurrence rate of evergreen broad-leaved plant and deciduous broad-leaved plant was low,but this phenomenon was slightly different from the plant combination of local modern vegetation.