Deformation bands

Deformation bands are small faults with very small displacements. In the past, these bands have been called Luder's bands or braided shear fractures. They often precede large faults. They develop in porous rocks, such as sandstone. Material in a deformation band has a much smaller grain size, poorer sorting, and a lower porosity than the original sandstone. They can restrict and/or change the flow of fluids like water and oil. They are common in the Colorado Plateau, where examples occur in the Entrada Sandstone in the San Rafael Swell in Utah.