近日，同济大学李超课题组最新的研究报道了，华东主要河流和边缘海碎屑沉积物Sr-Nd同位素特征及其物源示踪意义。该研究于2025年1月9日发表于《中国科学：地球科学》杂志。

据介绍，Sr-Nd同位素作为可靠的示踪剂，被广泛应用于沉积物物源研究中。本研究收集了中国东部主要河流（黄河、长江、东南沿海河流、台湾岛河流），以及边缘海（黄海、东海）和冲绳海槽采集的细粒表层沉积物的304Sr和335Nd同位素资料。这个全面的数据集使得研究人员，能够检查这些同位素的空间分布模式及其对物源分析的影响。

长江盆地和黄河盆地沉积物中εNd值的变化，主要反映了沉积物强度的多样性，而⁸⁷Sr/⁸⁶Sr比值受粒度和物源的双重影响。此外，长江中下游地区⁸⁷Sr/⁸⁶Sr比值的降低，除了单纯的粒度大小外，还应被归因于具有明显不同的⁸⁷Sr/⁸⁶Sr特征。在东南沿海河流和台湾河流中，胶河潮汐河段的沉积物呈现混合型特征，既有长江沉积物，也有当地集水区沉积物。

与之相反，闽江和九龙江沉积物主要反映了当地来源，长江对其影响较小。台湾岛东西两岸河流沉积物Sr-Nd同位素特征的显著差异，凸显了该地区岩石物源非均质性的多样性。对于边缘海，数据显示，南黄海和南黄海中部泥区表层沉积物主要来自长江流域，可能有来自朝鲜河流的输入。东海内陆架沉积物主要受长江输入的影响，而中陆架和外陆架的沉积物，主要受台湾岛东部河流的影响。

总体而言，进入中国东部边缘海的主要河流的，沉积物Sr-Nd同位素特征具有相当大的相似性，这对仅基于Sr-Nd同位素特征，来量化单个河流端元的贡献提出了实质性的挑战。为了提高沉积物从沉积到沉降过程定量评估的精度，必须为潜在的端元确定更窄范围的Sr-Nd同位素特征，并扩大这些边缘海的Sr-Nd同位素研究，特别强调超出当前研究范围的区域（如泥区）。

附：英文原文

Title: Sr-Nd isotopic characteristics and their significance in provenance tracing of detrital sediment in major rivers and marginal seas of eastern China

Author: Xiaobao GAO, Chao LI, Zhifei DUAN, Yulong GUO, Shouye YANG

Issue&Volume: 2025/01/09

Abstract: Sr-Nd isotopes are widely utilized as reliable tracers in sediment provenance studies. In this study, we compiled 304 Sr and 335 Nd isotope data of fine-grained surface sediments collected from major rivers in eastern China, including the Huanghe River, Changjiang River, southeastern coastal rivers, and rivers in Taiwan Island, as well as from marginal seas (Yellow Sea and East China Sea) and the Okinawa Trough. This comprehensive dataset allowed us to examine the spatial distribution patterns of these isotopes and their implications for provenance analysis. The variations of εNd values in the sediments in Changjiang and Huanghe Basins primarily reflect the diversity of sediment sources, whereas the ⁸⁷Sr/⁸⁶Sr ratios are influenced by both grain size and source provenance. Moreover, the reduction in 87Sr/86Sr ratios observed in the middle and lower Changjiang River is attributed to the inputs of sources characterized by distinct ⁸⁷Sr/⁸⁶Sr signatures beyond mere grain size effects. In the southeastern coastal and Taiwan rivers, sediments in the tidal reaches of the Jiao River exhibit hybrid characteristics, a mix of Changjiang-derived sediment and those originating from local catchments. Conversely, the Min River and Jiulong River sediments predominantly reflect local sources, with minimal influence from the Changjiang River. The significant isotopic variation of Sr-Nd isotopic characteristics observed between riverine sediments on the eastern and western sides of Taiwan Island underscores the diverse provenance heterogeneity of source rocks in the region. For the marginal seas, our data indicates that the surface sediments in the central mud area of the South Yellow Sea and the southern Yellow Sea are predominantly sourced from the Changjiang River catchment, potentially augmented by inputs from Korean rivers. The inner shelf sediments of the East China Sea are primarily influenced by Changjiang River inputs, whereas rivers in eastern Taiwan Island contribute to the sediments on the middle and outer shelves. Overall, the sediment Sr-Nd isotopic characteristics from the principal sources entering the eastern China marginal seas exhibit considerable similarity, presenting a substantial challenge for quantifying individual river end-member contributions based solely on the Sr-Nd isotopic signatures. To enhance the precision of quantitative assessments in sediment source-to-sink processes, it is imperative to define a narrower range of Sr-Nd isotopic signatures for potential end-members and to expand Sr-Nd isotopic investigations in these marginal seas, with a particular emphasis on regions beyond the current scope of investigations (such as mud areas).

DOI: 10.1007/s11430-024-1464-5

Source: https://www.sciengine.com/SCES/doi/10.1007/s11430-024-1464-5