硫的非质量分馏在晚太古代环境中的应用研究进展

Advances in the Application of Sulfur Mass-independent Fractionation in the Late Archean Environment

硫的非质量分馏是研究大气环境变化的重要指示剂,在太古代缺氧的环境下,二氧化硫的光化学反应会产生带正和负δ33 S的两个硫同位素端元,其产物分别赋存于黄铁矿和古海水硫酸根中。但前人的研究多集中于黄铁矿端元,而对于硫酸根,由于缺乏指示矿物,其研究较为薄弱且多有争议。从硫的非质量分馏产生机理、晚太古代地质记录中硫的非质量分馏的研究及大气化学实验的模拟研究三个方面进行综述,结合研究实例,分析了古海水硫酸根的可能来源,预测了硫的非质量分馏值的范围,提出晚太古代海水硫酸盐硫的非质量分馏效应将是今后研究的重点。

Sulfur mass-independent fractionation(S-MIF)is one of the most important tracers for studying atmosphere chemistry and evolution.In the Archean hypoxic environment,S-MIF signals produced by the photolysis of SO 2 could be preserved in two isotopically distinct sulfur aerosols(i.e.sulfate with the negativeδ33 S in the seawater and elemental sulfur with positiveδ33 S in pyrite).However,previous studies focused on pyrite end member,while for sulfates,due to lack of indicator minerals,their research is weak and controversial.The mechanism of sulfur mass-independent fractionation,the study of sulfur mass-independent fractionation in Late Archean geological records and the simulation of atmospheric chemistry experiments were reviewed.Combined with domestic research examples,the possible sources of sulfate in ancient seawater were analyzed,and the range of sulfur mass-independent fractionation value of sulfur was predicted.At last,the mass-independent fractionation effect of sulfate in Late Archean seawater sulfate was proposed to be the focus of future research.