Structural Changes in the Surface of a Heterogeneous Body (Xenolite) under Friction

The structure of the surface layer of a heterogeneous solid body (xenolite) before and after friction is studied by infrared and Raman spectroscopy. Before friction, the layer contained hornblende and pyroxene crystals. The friction resulted in partial transformation of pyroxenes into hornblende and the latter was transformed into montmorillonite clay. The xenolite surface is covered with a ~60-nm-thick layer of water.