摘要
碳酸盐岩的硫酸风化机制及其与碳循环的关系是全球碳循环研究中最为关注的科学问题之一,其关键问题是识别硫酸盐来源.通过分析长江干流丰水期SO4^2-浓度及其硫、氧同位素组成特征,探讨长江硫酸盐的来源及其主要控制因素.长江河水SO4^2-含量呈现逐年增加的趋势,并且年增幅度逐渐加大.δ^34 SSO4和δ^18 OSO4变化范围为-3.5‰-5.6‰和3.7‰-9.2‰,二者呈现显著的线性负相关关系.δ^18 OSO4值从上游到下游的增加趋势受长江水δ^18 OH2O值的空间组成特征的影响.研究表明,大气降水（酸雨）和硫化物氧化是控制长江干流丰水期河水硫、氧同位素组成及其来源的主要机制,为研究长江流域化学风化侵蚀作用和碳循环过程提供重要的理论依据.
Crustal weathering by sulfuric acid and its relationship with carbon cycling is a subject of greatest concern in the domain of global carbon cycling,with its key issue of the identification of riverine sulfate sources.In this study,stable sulfur and oxygen isotope compositions of riverine sulfate in the mainstream of the Yangtze River during rainy season are determined to trace the riverine sulfate sources and controlling factors.The SO4^2-concentration keeps increasing with ever-increasing annual growth rate.The isotope compositions of dissolved sulfate in the Yangze River range from-3.5‰ to 5.6‰ for δ^34 SSO4 and from 3.7‰ to 9.2‰ for δ^18 OSO4,showing a significantly negative linear correlation between δ^34 SSO4 and δ^18 OSO4.The tendency of increased δ^18 OSO4 values from upstream to downstream is controlled by δ18 OH2 Ovalues of the Yangtze River water.It is indicated that atmospheric acid deposition and sulfide oxidation are dominant sources of dissolved sulfate in the Yangze River.This study offers theoretical basis which facilitates further environmental explorations for chemical weathering of carbonate and carbon cycling.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2014年第11期1547-1554,1592,共9页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金项目(No.41202169)
中国博士后基金项目(No.2014M552114)
中央高校基本科研业务费专项资金资助项目(No.CUGL140407)
关键词
硫同位素
氧同位素
硫酸盐来源
长江
地球化学
sulfur isotope
oxygen isotope
sulfate source
the Yangtze River
geochemistry.
