地质与勘探2025，Vol.61Issue(4)：776-788,13.DOI:10.12134/j.dzykt.2025.04.009
化学风化指数在火山岩风化体风化程度和垂向分层(带)定量评价中的应用
Application of Chemical Weathering Index in Quantitative Analysis of Weathering Degree and Vertical Stratification(Zonation)of Volcanic Rock:Taking the Basalt in Western Guizhou Province as an Example
摘要
Abstract
The research on discriminating the weathering degree of rock masses(rocks)and dividing their vertical stratification(zonation)plays a critical role in selecting foundation surfaces for water conservancy and hydropower projects,road and bridge engineering,as well as in the risk assessment of adverse geological hazards such as instability of mine rock slopes and surrounding rock.In recent years,numerous chemical weathering indices have been widely used to reflect the weathering degree of sedimentary and volcanic rock masses(rocks).This work attempts to evaluate and optimize chemical weathering indices suitable for quantitative discrimination of weathering degree and vertical zonation(stratification)in weathered volcanic rock masses.Through literature surveys and comprehensive evaluation analyses,we systematically summarized 38 chemical weathering indices and their expressions commonly used in geomorphology,epigeochemical,geology,engineering geology,and other disciplinary fields.Particular emphasis was placed on reviewing the advantages and limitations of 12 chemical weathering indices(WPI,WIG,WIC,WIP,BWI,MIA,Ba,MWPI,W,CIA,A-FM,LOI)that previous studies considered sensitive to the weathering degree of volcanic rocks.Considering the variable geochemical behavior of the valence element Fe at different weathering stages,the relative change relationship between the decrease of FeO and the enrichment of Fe2O3 in rocks is important data reflecting the weathering degree of rock masses(rocks).Taken the basic basalt in western Guizhou as a case study,the oxidation degree OX=Fe2O3/(Fe2O3+FeO)was introduced as a criterion for dividing the vertical structure of weathered basalt.A complete discriminant standard for vertical six-layer division of weathered rock masses(stones)was established based on the oxidation degree OX values of basalt from different weathering layers:fresh parent rock(OX≤0.55),disintegration zone I(OX=0.55～0.65),disintegration zone II(OX=0.65～0.75),leaching zone(OX=0.75～0.90),and hydrolysis zone(OX>0.90),and the OX value of the soil layer is theoretically close to 1 due to the influence of the surface environment.The evolutionary characteristics of W,CIA,and A-FM in rocks from different weathering layers are similar to those of the oxidation degree OX,making them suitable for quantitative evaluation of weathering degree in weathered volcanic rock masses.However,LOI is not suitable for evaluating the weathering degree of basalt in the initial weathering stage,and eight chemical weathering indices(WPI,WIG,WIC,WIP,BWI,MIA,Ba,MWPI)are unsuitable for identifying the weathering degree of volcanic rocks.关键词
火山岩风化体/氧化度(OX)/化学风化指数/风化程度/垂向分层(带)性/玄武岩/黔西Key words
volcanic rock weathering mass/oxidation index(OX)/chemical weathering index/weathering degree/vertical stratification(zonation)/basalt/western Guizhou Province分类
天文与地球科学引用本文复制引用
刘德成,陈亚军..化学风化指数在火山岩风化体风化程度和垂向分层(带)定量评价中的应用[J].地质与勘探,2025,61(4):776-788,13.基金项目
中国地质调查局西安地质调查中心综合地质调查项目(编号:DD20190143). （编号:DD20190143）
