江汉平原周缘主要河流沉积物Sr-Nd同位素组成及其示踪意义  

Sr-Nd Isotopic Compositions of the Sediments from the Rivers Around the Jianghan Plain and Provenance Significance

作　　者：袁胜元[1,2] 邵磊[3,4] 李长安[4] 王节涛[3,4] 江华军[4] 

机构地区：[1]许昌学院城市与环境学院,许昌461000 [2]中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉430074 [3]中国地质调查局武汉地质调查中心,湖北武汉430205 [4]中国地质大学(武汉)地球科学学院,湖北武汉430074

出　　处：《海洋湖沼通报》2014年第2期177-182,共6页Transactions of Oceanology and Limnology

基　　金：国家自然科学基金项目(40971008;40771213);黄土与第四纪地质国家重点实验室开放合作基金项目(SKLLQG1208);河南省科技攻关项目(122102310421)资助

摘　　要：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 late Cenozoic sediments deposited in the Jianghan Plain recorded information on the evolution of the Yangtze River. Many researches have been carried out to find information on the prove-nance changing of these sediments and to reconstruct the evolution history of the Yangtze River. However, sediments from the rivers around the Jianghan Plain were neglected. In this study, systematic Sr-Nd isotopic compositions of sediments from the rivers around the Jianghan Plain were carried out to extract implications for the sediment source. The results showed that the sediments from the YangtzeRiver has the highest 143 Nd/m Nd values. ^143Nd/^144Nd values of sediments from the Hanjiang River aremore negative （lower） than those of the Yangtze River, but higher than those of the Juhe River and theZhanghe River. The Sr isotopic compositions of these sediments showed contrary variations. The Sr-Ndisotopic compositions of the sediments were well dominated by the source rocks distributed in the drainage basin. Based on the results, it was assumed that sediments of the Jianghan Plain should have muchlower （negative）^143Nd/^144Nd values before the modern Yangtze River was formed. However, the ^143Nd/^144Nd values should become higher （positive） after that. It showed that it was theoretically feasible to reconstruct the evolution history of the Yangtze River through the Sr-Nd isotopic variations ofsediments in the Jianghan Plain.

关 键 词：长江中游 江汉平原 锶-钕同位素 物源示踪 

分 类 号：P736.21[天文地球—海洋地质]