Slickenside

In geology, a slickenside is a smoothly polished surface caused by frictional movement between rocks along a fault.

[6] Curved slickenlines have recently been studied for their potential to preserve the direction of earthquake rupture propagation.

[11] When the particle size is reduced so dramatically that the surface becomes shiny, it can be characterized as a fault mirror.

[12] Once slip has stopped, this fluid solidifies as a silica gel, which appears shiny and hosts slickenlines.

Slickenfibres form in areas where the rock slowly creep past one another rather than sliding suddenly as a result of an earthquake.

Calcite slickenfibres have recently been used to constrain the depth of aseismic creep in the Zagros Mountains as well as the orientation of stress acting on the fault.

[15] It has also been suggested that when multiple slickenfibre or slickensteps orientations are present, it can indicate that the ongoing shear is not strain softening so slip does not have a constant direction.

In the Australian Soil Classification, slickensides, along with lenticular structural aggregates, are an indicator of a vertisol.

[18] On the Moon, a boulder with slickensides, discovered in a debris-strewn small crater at Station 9 near Rima Hadley, was photographed during a moonwalk by the crew of Apollo 15.