地质学报2016，Vol.90Issue(4)：818-832,15.
黑色页岩化学风化程度指标研究
A New Chemical Index of Identifying the weathering Degree of Black Shales
摘要
Abstract
Black shales are a type of sedimentary rocks that are characterized by large variation in chemical compositions both spatially and temporally.Therefore,the chemical indices,such as CIA(MIA),CIW, CIX,PIA, STI, R, WIP, V, and W, which are based on relatively homogeneous geochemical compositions of different igneous rocks,can not be used to identify the weathering degrees of black shale because they can not differ chemical compositions of parent rocks from that of weathered black shales and have low sensitivity and other problems.Therefore,it is necessary to establish a new chemical index to identify the weathering degree of black shale.In combination with the one-way ANOVA analysis and the multivariate discriminant analysis methods,this study conducted major elements analysis for the samples from fresh and weathered black shales of Lower Cambrian in central Hunan to define the differences of their chemical components.Establishment of major element discriminant method can further define chemical weathering index of weathering degree of black shales.It is shown that different major elements have different degree of influence on the chemical difference between the fresh and weathered black shales, and such influencing degree decreases with an order of TiO2 >Al2 O3 >Fe2 O3 >LOI>MnO>CaO>SiO2 >MgO>K2 O>Na2 O>P2 O5 .Chemical weathering index for identifying weathering degree of black shales (WB)can be established as follows:WB=28.8×ln(SiO2 )+16.67× ln(TiO2 )+10.52×ln(Al2 O3 )+5.62 ×ln(Fe2 O3 )-2.01×ln(MgO)+4.10×ln(CaO)-4.24×ln(K2 O)-5.06 ×ln(Na2 O)+5.07×ln(LOI)-158.13.This new chemical index can overcome the weakness of all the existed chemical indices,and can be used to identify the weathering degree of black shale.关键词
黑色页岩风化/风化程度/化学风化指数/主量元素/新鲜和风化黑色页岩/湘中Key words
the black shale weathering/the degree of chemical weathering/chemical weathering index/major element/fresh and weathered black shale/central Hunan province of China引用本文复制引用
吴蓓娟,彭渤,张坤,匡晓亮,涂湘林,方小红,曾等志..黑色页岩化学风化程度指标研究[J].地质学报,2016,90(4):818-832,15.基金项目
本文为国家自然科学基金（编号40572172，41073095）、湖南省高校科技创新团队支持计划资助的成果。 （）
