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江汉平原内部巨厚的晚新生代沉积物记录了长江形成与演化的信息。本文以流经江汉平原的几条主要河流为研究对象,以Sr-Nd同位素组成为指示荆,开展了其现代河流沉积物物源示踪研究。结果表明:流经江汉平原的几条主要河流中,长江水系沉积物具有最高的~(143)Nd/~(144)Nd值,汉江次之,漳河与沮河最低。Sr同位素组成呈现相反的变化趋势。各河流沉积物同位素组成与其流域内的源岩分布特征有很好的对应关系。由此认为,现代长江形成前后,江汉平原沉积物Sr-Nd同位素组成应有明显差异。这为在江汉平原内部通过沉积物Sr-Nd同住素组成变化探讨长江形成与演化提供了理论基础。
The huge Cenozoic sediments in the Jianghan Plain record the formation and evolution of the Yangtze River. In this paper, several major rivers through the Jianghan Plain as the research object, with Sr-Nd isotope composition as an indicator Jing, carried out its modern river sediment source tracing research. The results show that the Yangtze River sediments have the highest value of ~ (143) Nd / ~ (144) Nd among the major rivers flowing through the Jianghan Plain, followed by the Han River, the lowest of Zhanghe and Juhe. Sr isotope composition showed the opposite trend. The isotopic composition of sediments in each river has a good correspondence with the distribution of source rocks in its basin. Thus, before and after the formation of the modern Yangtze River, Jianghan Plain sediments Sr-Nd isotopic composition should be significantly different. This provides a theoretical basis for discussing the formation and evolution of the Yangtze River in the Jianghan Plain through the change of the Sr-Nd composition of sediments.