Slickensides

Slickensides are smooth, shiny surfaces that form on rock fault lines where two blocks of earth have slid past each other during an earthquake or other tectonic activity. These surfaces are created when the intense pressure and friction cause the rock to grind down, resulting in a polished appearance. They often display striations, or grooves, that can indicate the direction of movement. Geologists study slickensides to understand fault mechanics and the history of geological events in an area, providing insight into how the earth has changed over time.