Morphology of intergranular pores and wetting angles in pelitic schists studied by transmission electron microscopy
Morphology of intergranular pores and wetting angles in pelitic schists studied by transmission electron microscopy
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DOI：
10.1007/s004100100263
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发表时间：
2001-08-01
影响因子：
3.5
通讯作者：
Akizuki, M
中科院分区：
文献类型：
--
作者：
Hiraga, T;Nishikawa, O;Akizuki, M
在主要由石英和钠长石颗粒组成的泥质片岩中，用透射电镜（TEM）研究了充水的晶间孔隙形态。虽然有些孔隙是由晶体平面（f面）定义的，但它们的大多数形式具有由颗粒和流体之间的界面张力决定的理想形状。高分辨率透射电镜观测表明，在纳米尺度下，该岩石的晶界无孔区致密，表明该岩石的润湿角大于0度。两粒结合部的孔隙分布可以比作由微裂纹引起的沿边界的流体膜不稳定而形成的“项链微观结构”。石英和钠长石颗粒边缘孔隙的润湿角依次为钠长石/钠长石、石英/石英、石英/钠长石。无方解石样品的石英/石英润湿角小于含方解石样品。这个角度也会因晶粒取向错误而改变。研究结果证实，固体-固体和固体-流体界面能控制天然岩石中粒间流体的几何形状。
In pelitic schists composed mainly of quartz and albite grains, the morphology of intergranular pores, which were filled with water, was studied by transmission electron microscopy (TEM). Although some pores are defined by crystallographic planes (F-face), most of their form has an ideal shape determined by interface tensions between grains and fluid. High-resolution TEM observations demonstrate that pore-free regions at grain boundaries are tight even at the nanometer scale, showing that the wetting angle is larger than 0 degrees in this rock. The pore distribution in two-grain junctions can be compared to a "necklace microstructure" developed by instability of a fluid film along the boundary induced by microcracking. Wetting angles for pores located at grain edges of quartz and albite decrease in the order albite/ albite, quartz/quartz, and quartz/albite. The quartz/ quartz wetting angle in a calcite-free sample is smaller than that in a calcite-containing sample. This angle also changes due to grain misorientation. Our results confirm that solid-solid and solid-fluid interfacial energies control the geometry of intergranular fluid in natural rocks.