Neodymium isotopic variations of the late Cenozoic sediments in the Jianghan Basin: Implications for sediment source and evolution of the Yangtze River

The Yangtze River originates from eastern Asia and is one of the most important components of the East Asia river system. In this study we applied bulk Nd isotopic analysis to identify the sediment provenance in the Jianghan Basin, middle Yangtze River and tried to provide useful information on the evolvement of the Yangtze River. The fine-grained (<0.058 mm) sediment samples were selected from a continuous borehole in the Jianghan Basin and analyzed for Nd isotopic compositions. The 143Nd/144Nd ratios vary between 0.512042 and 0.512239, with an average of 0.512144. The εNd(0) values vary between −11.6 and −7.8, with an average of −9.6. Nd isotopic compositions cannot provide compelling evidence to prove whether the Pliocene sediments in the Jianghan Basin were influenced by the source rocks in the Jinshajiang area characterized by extremely high (positive) εNd(0) values. While these source rocks made a great contribution to the Jianghan Basin during the Quaternary. Less negative εNd(0) values reflect preferential erosion of source rocks in the Jinshajiang drainage. The Nd variations reflected changes in erosion patterns during the Quaternary. Based on the provenance analysis of the Jianghan Basin sediments, we propose that the Yangtze River appears to develop into a large river similar as the modern Yangtze no later than the beginning of the Quaternary.

► We report the Nd variations of the Jianghan Basin for the first time. ► The Pliocene and Quaternary sediments show different Nd compositions. ► During the Quaternary different Nd compositions indicate different patterns of erosion. ► The Jianghan Basin shows higher Nd values than the Yangtze Delta. ► The modern Yangtze was formed no later than the beginning of the Quaternary.