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高校地质学报 ›› 2022, Vol. 28 ›› Issue (1): 51-63.DOI: 10.16108/j.issn1006-7493.2020118

• 岩石·矿床·地球化学 • 上一篇    下一篇

常用化学风化指标综述:应用与展望

李绪龙,张 霞*,林春明,黄舒雅,李 鑫   

  1. 内生金属矿床成矿机制研究国家重点实验室,南京大学 地球科学与工程学院,南京 210023
  • 出版日期:2022-02-20 发布日期:2022-02-20

Overview of the Application and Prospect of Common Chemical Weathering Indices

LI Xulong,ZHANG Xia*,LIN Chunming,HUANG Shuya,LI Xin   

  1. State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
  • Online:2022-02-20 Published:2022-02-20

摘要: 常用化学风化指标诸如帕克风化指数(WIP)、化学蚀变指数(CIA)、成分变异指数(ICV)、CIX指数和αAlE常被用于评价源区化学风化强度,但利用以上化学风化指标评价化学风化强度时要考虑不同指标的控制因素,否则会导致风化评价结果失真。文章认为以最常用化学风化指标探究源区化学风化过程时,应在了解源区地质信息的情况下,选取合适的的细粒物质或悬浮物作为样品减弱粒度的控制作用,通过酸处理去除杂质,再利用Sc/Th-CIA 判别图反映物源信息,Th/Sc-Zr/Sc判别图进一步判别沉积分异和沉积再旋回的控制作用,进而选取ICV>1的样品排除再旋回作用的干扰,用A-CN-K图或Panahi(2000)提出的公式进行钾交代作用的校正,最终通过CIA计算得出源岩化学风化强度。为确保准确反映源区风化情况,利用SPSS进行CIA受控因子分析,进而构建研究区的特征风化指标。

关键词: 化学风化指标, 控制因素, 物源, 沉积分异, 再旋回, 钾交代作用

Abstract: Common chemical weathering indices such as the Weathering Index of Parker (WIP), the Chemical Index of Alteration (CIA), the Index of Compositional Variability (ICV), CIX index and αAlE are often used to evaluate the chemical weathering intensity of source areas. But the factors which controlling the above chemical weathering indices should be considered, otherwise the results of the weathering evaluation will be distorted. This paper argues that the geological survey of source area should be known when chemical weathering indices are used to study the chemical weathering process. The selection of fine sediments or suspended matter can weaken the influence of grain size on chemical weathering indices. The impurities in the sediments are removed by acid treatment. Then, the Sc/Th-CIA diagram was used to reflect the material source information, Th/SC-Zr/Sc diagram was used to further distinguish the control effect of sedimentary differentiation and sedimentary recirculation, and then the samples with ICV value less than 1 were selected to eliminate the interference of recirculation. The A-CN-K diagram or the formula proposed by Panahi (2000) were used to correct the potassium metasomatism, and the strength of chemical weathering of source rocks was evaluated by CIA eventually. To ensure that the calculation of chemical weathering indices can accurately reflect the weathering situation of the source area, SPSS software can be used to analyze the proportion of some factors which affecting the CIA to construct characteristic weathering index of the study area.

Key words: chemical weathering indices, factors, source, sedimentary differentiation, sedimentary recirculation, potassium
metasomatism

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