基于结构体的峨眉山玄武岩风化程度评价(Ⅱ):玄武岩斜坡地下水及浸泡液水文地球化学

The assessment of the intensity of Emeishan basalt weathering based on rock blocks(Ⅱ):hydrogeochemistry of the groundwater in the basalt slope and basalt soaking solution

岩石风化过程中的元素活动性评价除应考虑该元素在风化产物中残留与淋失状况及在淋滤液(地下水及室内浸泡液等)中的浓度外,还应考虑其在母岩中的相对含量。峨眉山玄武岩斜坡地下水及室内浸泡液中各元素原子个数比值与母岩中对应比值之间均存在显著差异,其造岩矿物的非全等溶解特征显著。综合考虑风化过程中的岩石成分变化、斜坡地下水及室内浸泡液化学成分确定的峨眉山玄武岩风化过程中的元素活动性顺序为Ca>Na>Mg≥Si>K>Fe。活动性强或惰性程度高、对风化程度变化响应敏感应成为岩石风化程度指示性元素的选择标准,Ca和Fe应成为峨眉山玄武岩风化程度评价的首选元素。

The evaluation of the element mobility in the process of rock weathering should consider not only elements fixation and leaching status and their concentrations in the leachate（groundwater and laboratory soaking solutions,etc.）,but also their relative content in the parent rocks.The ratios of atomic numbers of different elements in the groundwater in Emeishan basalt slope and laboratory soak solution are different from those in basalt parent rocks.The rock-forming mineral dissolution of Emeishan basalt is incongruent.According to the basalt composition change in the course of weathering and the chemical compositions of the groundwater in the basalt slope and the laboratory basalt soaking solutions,the element mobility sequence in Emeishan basalt weathering process of Ca Na Mg ≥ Si K Fe was determined.Mobile elements sensitive to the degree of weathering or immobile elements should be selected as indicative elements of the rock weathering degree,and Ca,Fe should be the preferred elements to evaluate the weathering intensity of the Emeishan basalt.