基于结构体的峨眉山玄武岩风化程度评价(Ⅲ)——既有风化指数评价  

The assessment of the weathering intensity of Emeishan basalt based on rock blocks(Ⅲ):Assessment of existing chemical weathering indices

作　　者：徐则民[1,2] 黄润秋[2] 

机构地区：[1]昆明理工大学土木系,云南昆明650500 [2]地质灾害防治与地质环境保护国家重点实验室,四川成都610059

出　　处：《中国地质》2013年第5期1655-1665,共11页Geology in China

基　　金：国家自然科学基金-云南联合基金重点项目(U1033601);国家自然科学基金面上项目(40572159;40772189);教育部高等学校博士点基金项目(20060674009);地质灾害防治与地质环境保护国家重点实验室开放基金项目(GZ2007-1;GZ2009-10)资助成果

摘　　要：以峨眉山玄武岩核心区7个区域的13个具有壳核结构的玄武岩结构体为基础,对主要风化指数的适宜性进行了研究。18个风化指数均不适合于风化初期的峨眉山玄武岩风化程度评价。能够指示风化中后期峨眉山玄武岩风化程度的指数包括Parker指数、BA1、BA、BA3、BA2、碱/铝指数、碱/倍半氧化物指数、WPI、SA、SF、Kr、硅/倍半氧化物、CIW、CIA及LOI,其中更为合理的是碱/铝指数、碱/倍半氧化物指数和硅/倍半氧化物。17个风化指数中,指示性最差的是A、B和B1。Fe2O3控制着风化初期峨眉山玄武岩碱/倍半氧化物指数、SF、Kr及硅/倍半氧化物的变化,应成为风化程度评价需要考虑的重要因素。The suitability of main weathering indices has been studied based on 13 weathered basalt blocks with core-shell structure from 7 rock mass sections in the core area of Emeishan basalt. Poor correlation has been observed between 18 chemical weathering indices and the early-stage weathering grade of the Emeishan basalt. The indices that can be used to evaluate mid-late period weathering degree of the Emeishan basalt include Parker＇s index, BA1, BA, BA3, BA2, alkali/alumina ratio, alkali/R2O3 ratio, WPI, SA, SF, Kr, silicate/R203 ratio, CIW, CIA and LOI, in which, alkali/alumina ratio, alkali/R2O3 ratio and silicate/R2O3 ratio are more reasonable, while A, B and B1 are the worst. Fe203 that controls the alkali/R2O3 ratio, SF, Kr and silicate/R2O3 ratio in the initial weathering stage of Emeishan basalt should be regarded as an important factor to evaluate the weathering degree of Emeishan basalt.

关 键 词：峨眉山玄武岩 风化程度 化学风化指数 适宜性 

分 类 号：P588.145[天文地球—岩石学]