摘要
为了深化对花岗岩风化过程和机理的认识,以青岛市黄岛区小黄山中生代风化壳剖面为例,分析其常、微量元素及磁化率值的纵向变化规律,探讨花岗岩风化壳的风化特征,建立花岗岩风化壳的风化模式。结果显示:小黄山花岗岩风化壳为硅铝黏土型风化壳,底部以物理破碎为主,顶部主要受化学风化、生物风化作用影响;自下而上Al、Fe、Si、Rb等元素富集,K、Na、Ca、Mg等碱金属元素大量淋失;Rb/Sr、化学蚀变指数(chemical index of alteration,CIA)随化学风化作用增强逐渐升高;磁化率呈现稳定—降低—异常高值—升高—降低—升高6个阶段。结合当地气候、地貌条件及矿物蚀变特征将剖面自下而上划分为6层,即基岩、风化前缘、崩解层、破碎层、淋溶层、土壤层,并建立小黄山花岗岩的风化模式,为黄岛地区花岗岩风化壳垂直分带和风化特征的研究提供理论依据,并为地下风化壳油气储层特征的研究提供一定的借鉴。
In order to promote the understanding of the weathering process and mechanism of granite,and to explore the weathering characteristics of granite weathering shells,the microbiotic weathering shell profile of Xiaohuangshan in Huangdao District,Qingdao City is taken as a model for the following items:1)discussing and analyzing the vertical variation of its normal;2)tracing the elements and susceptibility values;3)discussing the weathering characteristics of granite weathering shells;4)establishing the weathering mode of the granite weathering shells.The results show that the weathering crust of Xiaohuangshan granite is a silicon aluminum clay type weathering crust,the bottom is mainly physically broken,and the top is mainly affected by chemical and biological weathering.From bottom to top,Al,Fe,Si,Rb and other elements are enriched,and alkali metal elements such as K,Na,Ca,Mg and other alkali metal elements are leached in large quantity;Rb/Sr and chemical index of alteration(CIA)indices gradually increase with the enhancement of chemical weathering.The susceptibility value presents six stages of“stability-decrease-abnormally high value-increase-decrease-increase”.In combination with the local climate,geomorphic and mineral alteration characteristics,the section is divided into six members from bottom to top:basement rock,weathering front,disintegration layer,broken formation,leached layer,soil horizon.Morerover,the weathering mode of Xiaohuangshan granite is established,which can not only provides a theoretical basis for the study of vertical zoning and weathering characteristics of granite weathering shells in Huangdao area but also has certain reference value for the study of the characteristics of underground weathered shell reservoirs.
作者
胡君达
张立强
严一鸣
HU Junda;ZHANG Liqiang;YAN Yiming(School of Geoscience,China University of Petroleum,Qingdao,Shandong 266580,China)
出处
《中国科技论文》
CAS
北大核心
2023年第5期477-485,共9页
China Sciencepaper
基金
中国科学院战略性先导科技专项(A类)(XDA14010202)
国家自然科学基金资助项目(42002145)。
关键词
花岗岩风化壳
元素
磁化率
风化系数
风化模式
granite weathering crust
elements
magnetic susceptibility
weathering coefficient
weathering mode
