| 头寨滑坡玄武岩腐岩的岩石化学和矿物学特征 |
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| 引用本文： | 王志兵,徐则民.头寨滑坡玄武岩腐岩的岩石化学和矿物学特征[J].矿物学报,2008,28(4). |
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| 作者姓名： | 王志兵 徐则民 |
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| 作者单位： | 昆明理工大学,土木系,云南,昆明,650224 |
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| 基金项目： | 国家自然科学基金，教育部高等学校博士学科点专项科研基金，云南省自然科学基金，地质灾害防治与地质环境保护国家重点实验室开放基金 |
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| 摘 要： | 利用化学全分析、薄片鉴定及扫描电镜等测试、观察手段,分析了头寨滑坡发生的岩体玄武岩及其腐岩玄武岩腐岩的岩石化学和矿物学特征。化学全分析结果表明新鲜玄武岩与核心石在除Fe外,其它组分无明显的改变;核心石在转变为腐岩过程中Si、Ca、Na、Mg等元素逐渐流失,Fe、Al等逐渐富集,同时烧失量LOI和化学蚀变指数CIA显著增加,硅铝比逐渐减少。薄片鉴定表明主要矿物化学风化作用顺序为玻璃质、辉石、斜长石,与造岩矿物风化稳定性序列一致,腐岩中主要的次生矿物为蒙皂石及绿泥石。在扫描电镜下观察到风化前锋形态曲折,风化前锋附近矿物呈现物理裂痕,沿着解理面更易出现,风化前锋两侧的岩石矿物形态差异显著。岩体的化学-物理耦合风化作用不仅表现在宏观尺度上,而且在细观-微观的尺度上更为明显。铁元素的价态变化存在于玄武岩腐岩形成的整个过程之中并导致岩石体积增大,从而产生物理裂纹。
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| 关 键 词： | 头寨滑坡 玄武岩 腐岩壳 化学-物理耦合风化 |
PETROCHEMISTRY AND MINERALOGY OF BASALT SAPROLITE IN TOUZHAI LANDSLIDE |
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| WANG Zhi-bing,XU Ze-min.PETROCHEMISTRY AND MINERALOGY OF BASALT SAPROLITE IN TOUZHAI LANDSLIDE[J].Acta Mineralogica Sinica,2008,28(4). |
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| Authors: | WANG Zhi-bing XU Ze-min |
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| Abstract: | Petrochemical and mineralogical characteristics of fresh basalt and its saprolite from Touzhai landslide in Zhaotong,Yunnan Province,are described in terms of chemical analyses,optical observations of thin sections and SEM(scanning electron microscopic) observations.Chemical analysis showed that the fresh basalts and corestones slightly changed in composition except that variations in Fe2 to Fe3 are most noticeable.In the course of corestones changing to saprolite elements of Si,Ca,Na and Mg,the ratio of SiO2/Al2O3 decreased gradually,while the elements of Fe,Al and the values of LOI and CIA significantly increased.The weathering front under SEMs is tortuous,and physical weathering cracks which are of easier emergence along the cleavage plane can be observed in the vicinity of the weathering front.The major minerals follows the weathering order of dissolution of glass,pyroxene and feldspar,which is in agreement with the sequence of weathering-resistant minerals.The main secondary minerals are smectite and chlorite.Rock coupling chemical weathering with physical weathering processes not only exists on a macro-scale,but also on a meso-and micro-scale.Changes in the valence of iron took place in the whole formation process of basalt saprolite,thus leading to a volume increase,giving rise to physical cracks. |
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| Keywords: | Touzhai landslide basalt saprolized crust the coupling of chemical weathering and physical weathering |
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