Abstract
In order to clarify generation process of slickenside, we observed the microstructures of slickenside developed in chert, limestone and greenstone. The present result is the following. The slickenside is generated during faulting due to slip concentration only within 50 nm – 100 nm in width from slip surface. This layer is composed of very tiny flattened grains with 50 nm-100 nm in diameter and ca. 10 nm in height. These grains is probably formed by crashing the fault fragment. This generation process of slickenside is similar to that of tribofilm. Now we study those of serpentinite and coal seam.