近百年来长江荆江段牛轭湖沉积的孢粉、炭屑特征及其环境意义——以天鹅洲、尺八湖为例
发布时间：2019-05-22 16:34
【摘要】：根根据长江荆江段沿江牛轭湖天鹅洲和尺八沉积钻孔柱样,在建立了高分辨率的年代框架的基础上,分别进行了沉积物孢粉、炭屑分析,并结合荆州市1955~2012年的气候数据、史志记载的洪水和火灾等环境事件进行了综合分析。结果显示:天鹅洲、尺八两湖泊钻孔沉积物的孢粉和炭屑特征均较好地响应了近百年来湖区周边的环境变化;牛轭湖在裁断成湖之前、成湖之后的孢粉、炭屑特征不同:成湖之前,沉积物总孢粉浓度与乔木、灌木孢粉浓度都相对较低,水生植物和蕨类植物孢粉浓度相对较高,成湖之后乔木孢粉浓度仍呈减小趋势,但灌木、水生植物孢粉浓度呈波动增加趋势;利用沉积物炭屑浓度与孢粉浓度的比值(C/P值)指标,可以较好地指示自然山火与人类聚居地火灾等燃烧事件在沉积物中的记录,而且综合利用C/P值与沉积物孢粉特征,有可能厘清长江全流域洪水与局地洪涝事件的沉积记录。
[Abstract]:According to the samples of Swan Island and Zipa sedimentary drilling columns along the Jingjiang River section of the Yangtze River, and on the basis of establishing a high resolution chronological framework, the sediment sporopollen and carbon chips were analyzed, and the climate data of Jingzhou City from 1955to 2012 were combined with the data of sediment sporopollen and carbon chips. The environmental events such as floods and fires recorded in historical records are comprehensively analyzed. The results show that the sporopollen and carbon chip characteristics of bored sediments in Swan Island and Zhiba lakes respond well to the environmental changes around the lake area in the past hundred years. Before and after the formation of the lake, the characteristics of sporopollen and carbon chips in Niuyohu Lake are different: before the formation of the lake, the total sporopollen concentration in sediments is relatively low with that in trees and shrubs, and the sporopollen concentration in aquatic plants and ferns is relatively high. After the formation of the lake, the sporopollen concentration of trees still decreased, but the sporopollen concentration of shrubs and aquatic plants fluctuated and increased. The ratio of carbon chip concentration to sporopollen concentration in sediments (C 鈮，
本文编号：2483073
[Abstract]:According to the samples of Swan Island and Zipa sedimentary drilling columns along the Jingjiang River section of the Yangtze River, and on the basis of establishing a high resolution chronological framework, the sediment sporopollen and carbon chips were analyzed, and the climate data of Jingzhou City from 1955to 2012 were combined with the data of sediment sporopollen and carbon chips. The environmental events such as floods and fires recorded in historical records are comprehensively analyzed. The results show that the sporopollen and carbon chip characteristics of bored sediments in Swan Island and Zhiba lakes respond well to the environmental changes around the lake area in the past hundred years. Before and after the formation of the lake, the characteristics of sporopollen and carbon chips in Niuyohu Lake are different: before the formation of the lake, the total sporopollen concentration in sediments is relatively low with that in trees and shrubs, and the sporopollen concentration in aquatic plants and ferns is relatively high. After the formation of the lake, the sporopollen concentration of trees still decreased, but the sporopollen concentration of shrubs and aquatic plants fluctuated and increased. The ratio of carbon chip concentration to sporopollen concentration in sediments (C 鈮，
本文编号：2483073
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