三河—蓟州全新世泥炭形成时代及古环境意义

    Formation age and palaeoenvironment significance of Holocene peat in Sanhe- Jizhou area

    • 摘要: 燕山南麓山前冲洪积平原区广泛分布泥炭层,但其形成时代存在争议,对区域气候环境的相关研究也较为薄弱。针对河北三河—天津蓟州典型泥炭剖面开展14C测年工作,结合孢粉等指标进行分析,将泥炭层成炭时代主体划分为两期,并分别研究了其形成时的环境特征。结果表明: 14C测年显示蓟州头营泥炭层成炭期为全新世早期(10 500 a B.P.),三河不老淀泥炭层主体形成于全新世晚期(3 500~2 400 a B.P.)。根据蓟州头营泥炭层及下伏地层的孢粉组合特征,结合前人在不老淀泥炭层开展的孢粉研究成果及动植物化石组合特征,推测全新世早期气候由暖湿向温凉偏湿转变。研究成果可为区域第四系划分及古环境恢复提供依据。

       

      Abstract: The peat layer was widely distributed in piedmont alluvial plain of the southern Yan Mountains. However, its formation age is still controversial, with relatively weak relevant research of climate environment. The 14C dating work of typical peat profiles was conducted from Sanhe in Heibei Province to Jizhou in Tianjin. The peat formation time was divided into two periods, on the basis of sporopollen and other proxy indicators, and its environment characteristics were also studied. 14C dating showed that the cool-forming period of Touying peat layer in Jizhou was Early Holocene (10 500 a B.P.), and the main body of Bulaodian peat layer in Sanhe was Late Holo-cene (3 500~2 400 a B.P.). The climate of Early Holocene was inferred to be from warm and humid to cool and slightly humid, according to sporopollen assemblage features of Touying peat layer and its underlying stratum in Jizhou and the previous sporopollen research of Bulaodian peat layer and other fossil assemblage. This research could provide basis for the Quaternary stratigraphic division and paleoenvironment restoration in this area.

       

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