针对地震液化脉体与臼齿构造在宏观上不易辨认的问题。利用电子探针技术对脉体和含脉体围岩做了定性和定量研究,液化脉中Si、K、Al、Mg明显高于含脉体围岩,而Ca、Sc则表现为含脉体围岩高于脉体;在地震突发振动力作用下,富水软沉积层液化泄水,塑性碳酸盐沉积物随水部分流失,使得单位面积内碳酸盐沉积含量低于围岩,Ca、Sc具有相似的化学性质,表现为脉体中Ca、Sc含量偏高;因脉体中易溶物质流失,使得难溶的Si质和炭质相对含量变大。对脉体和含脉体围岩纹层中的方解石定量研究显示,两者方解石的各元素含量几乎相同,表现出明显的同源性,表明脉体是层内物质。结果显示,地震液化脉与臼齿构造在微观特征明显不同,为事件地层的鉴别提供了新的思路。
Aiming at the difficulty in recognition of seismic liquefied veins and molar-tooth structure, qualitative and quantitative research were carried out on veins and vein-bearing carbonate rocks using electron microprobe techniques. The results show that: (1) the value of Si, K, A1, Mg of the veins is significantly higher than that of the vein-bearing carbonate rocks, while the value of Ca and Sc is more abundant in the vein-bearing carbonate rocks. Ca and Sc have similar chemical properties, which are likely to be dissolved in water during the erosion process of carbonate rocks. That may be the result of water escape process. The loss of the soluble substances of veins leads to the relative increase of the insoluble Si and carbonaceous substances; (2)The quantitative research on the calcite of the veins and the vein-bearing carbonate rocks shows that the element component of the both is almost equal, which suggests obvious homology. So the veins should be the material within the stratal beds. In addition, the analysis result is evidently different from the previous study of molar-tooth structures. The veins from carbonate rocks of Dachenling Formation have the unique petrological, structural and geochemical features, so they should be interpreted to be seismic liquefied veins.