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江汉平原肖寺地区在3098aB.P.至1326aB.P.间形成了约200cm的河流及漫滩沼泽相沉积,在对该地区一个典型剖面沉积特征初步研究的基础上,以2.5cm为间距,对剖面的12.5～197.5cm段系统采集了79个样品,并进行了粒度和质量磁化率的测定与分析。结果表明:沉积物磁化率值的大小与沉积相,尤其是与沉积物的粒度存在相关性。一般规律是河流相粉砂的磁化率值大,而湖沼相粉砂质粘土及泥炭的磁化率值偏低。粒度和磁化率值的变化在一定程度上指示了古水文事件,粗砂组分含量及磁化率的高峰可能指示了特大越岸洪水事件。粒度和磁化率值变化同时也揭示了江汉平原肖寺地区冷期洪水事件频率明显高于暖期,可能与西风带的范围与强度有关。
The Shahei area in the Jianghan Plain formed about 200 cm of river and floodplain swamp sedimentary facies between 3098aB.P. and 1326aB.P. On the basis of a preliminary study on the sedimentary characteristics of a typical section in the area, A total of 79 samples were collected from the section of 12.5 ~ 197.5cm section and the magnetic susceptibility and particle size were measured and analyzed. The results show that there is a correlation between the susceptibility value of sediments and the sedimentary facies, especially the sediment grain size. The general rule is that the susceptibility of fluvial silt is large, while the susceptibility of lacustrine silty clay and peat is low. The change of grain size and magnetic susceptibility values to a certain extent indicate the paleo-hydrological events. The content of coarse sand and the peak of magnetic susceptibility may indicate the event of over large flood. The change of grain size and susceptibility also revealed that the frequency of flood events in Xiaosi area of Jianghan Plain was significantly higher than that of warm period, which may be related to the extent and intensity of the westerlies.