黄河中游流域河水B来源及其迁移转化的同位素示踪研究

B isotopic composition is a powerful tool to trace water-particles interaction within catchments. Study on B geochemistry in river system becomes a hot spot of catchment erosion research. B contents in river water of middle reach is higher than that of upper reach and lower reach, while the changes of B isotopic compositions in river water of middle reach is complicated in Huanghe River, indicating that there are different sources and transport and transformation of B affecting B isotopic compositions. Presently, studies on B sources and B isotopic compositions in the middle reach of Huanghe River catchment are limited. This project selects the middle reach of Huanghe River as the study subject; collecting weathering crust and soil profiles covering different types, suspended particulate and sediments in river water on loess plateau. The different sources and transport and transformation of B related to weathering of rocks and soils and suspension and sediment of solutes will be studied. This study will also focus on the B sources and their contributions from coal and recharge of groundwater of middle reach in Huanghe River. The above research is supplemented by adsorption−leaching experiments in the laboratory to elucidate the sources and transport and transformation of B that affects B isotopic changes in river water of middle reach in Huanghe River catchment. The aim of this project is to enlarge the understanding the geochemical characteristics of B during physical-chemical erosion processes in the Huanghe River catchment, and enrich and perfect B isotopic geochemical theory during water−rock interactions at earth’s surface.

B同位素具有示踪流域水-粒作用过程的能力。河流体系B同位素地球化学是近年来流域侵蚀研究的热点。黄河中游河水B含量明显高于上下游，但B同位素变化并无规律，指示可能存在多种B源及迁移转化过程影响河水B同位素分馏。现阶段对黄河中游流域大面积黄土分布区河水B源和B同位素变化机理的研究鲜见报道。本项目以黄河中游流域为研究对象，采集黄土高原不同类型的风化壳和土壤剖面、河水悬浮物和沉积物，研究黄土高原岩石/土壤风化过程以及河流溶质悬浮/沉积过程相关的B的不同来源及其迁移转化特征，并关注与煤和地下水补给有关的河水B源和工农业污染的贡献，辅以室内吸附−淋滤实验阐明黄河中游河水B的来源及其迁移转化过程对河水B同位素变化的影响，以期加深对黄河流域物理和化学侵蚀过程B同位素地球化学特征的认识，丰富和完善流域水-岩作用相关的B同位素地球化学理论。