Elucidation for behavior of pore fluid in a sediment resulted in wet-sedimet deformation

湿沉积变形可分为脆性变形和韧性变形两种类型。前者以发育断裂或无平面断裂为代表，后者以变形改造原生沉积构造为特征。基于x射线CAT扫描层析图的具体图像、扫描电镜观察和压汞式孔隙计检测的孔隙分布，可以检测出健康断层面的详细容重分布，这是一个复杂而非想象的过程。在脆性变形过程中，裂缝（次生孔隙）的形成和原有孔隙的剪切作用改变了孔隙的分布模式。在同一断裂面的某一部分，粘土矿物明显变形（叠瓦状），伴生的孔隙往往被破坏，孔隙度小于未变形的包裹体。另一方面，同一断平面内相邻部分裂缝发育，孔隙分布变化不大，导致孔隙度大于未变形的包裹体。因此，在健康断层的同一平面上可以识别出孔隙度的正、负异常，表明叠瓦状区域对孔隙水的排出起重要作用，而裂缝可能是孔隙水的储集层，两者的发育是控制脆性变形阶段沿断层流动行为的重要因素。在延性变形沉积物和相邻的非变形沉积物之间，孔隙分布模式存在显著差异，但孔隙度没有差异。延性变形可能使孔隙分布呈高斯型单峰分布，表明延性变形应使孔隙分布重组为比原始未变形时更简单的模式。

Two deformation styles, the brittle and ductile deformations, are recognized in wet-sediment deformation. The former is represented by a healted fault or planeless fault, and the latter is characterized by deformation that have modified the primary sedimentary structure. Based on the specific image of X-ray CAT scan tomogram, SEM observation and the pore distribution detected by Mercury injection type porosimeter, it enables to examine the detailed bulk-density distribution in a healt fault plane, that is complicated rather than expected. In the brittle deformation, the pore distribution pattern is changed by formation of fracture (secondary pore) and shearing of preexisting pores. In a part of the same fault plane, the clay minerals are obviously deformed (imbricated) and the associated pores are often broken and makes porosity smaller than htat of the non-deformed surrounds. On the other hand, fractures are developed in the adjacent part within the same fault plane, where any change in pore distribution is not identified, that cause the porosity larger than the non-deformed surrounds. Hence, the positive and negative anomaries in porosity can be recognized in the same plane of a healt fault, suggesting that the imbricated domain should play important role to expell the pore water whereas the fractured is likely to behave as a reservior of the pore water, then the developments of the both is important factor in controlling flow behavior along a fault in a brittle deformation stage. Significant difference in pore distribution pattern is identified between the ductile-deromed and the adjacent non-deformed sediments although any differences in porosity can not be detected. The ductile deformation is likely to make the pore distribution Gaussian-like unimodal distribution, suggesting that the ductile defromation should cause reorganization of the pore distributuion to be more simple pattern than the primary non-deformed one.