【摘要】：根根據(jù)長江荊江段沿江牛軛湖天鵝洲和尺八沉積鉆孔柱樣,在建立了高分辨率的年代框架的基礎(chǔ)上,分別進行了沉積物孢粉、炭屑分析,并結(jié)合荊州市1955~2012年的氣候數(shù)據(jù)、史志記載的洪水和火災(zāi)等環(huán)境事件進行了綜合分析。結(jié)果顯示:天鵝洲、尺八兩湖泊鉆孔沉積物的孢粉和炭屑特征均較好地響應(yīng)了近百年來湖區(qū)周邊的環(huán)境變化;牛軛湖在裁斷成湖之前、成湖之后的孢粉、炭屑特征不同:成湖之前,沉積物總孢粉濃度與喬木、灌木孢粉濃度都相對較低,水生植物和蕨類植物孢粉濃度相對較高,成湖之后喬木孢粉濃度仍呈減小趨勢,但灌木、水生植物孢粉濃度呈波動增加趨勢;利用沉積物炭屑濃度與孢粉濃度的比值(C/P值)指標(biāo),可以較好地指示自然山火與人類聚居地火災(zāi)等燃燒事件在沉積物中的記錄,而且綜合利用C/P值與沉積物孢粉特征,有可能厘清長江全流域洪水與局地洪澇事件的沉積記錄。
[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，

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