Pull-apart Basin

A pull-apart basin is a structural depression in the crust of the Earth that forms where two overlapping strike-slip faults, or a bend in a single fault, create a zone of crustal extension between them. Where the offset between the faults matches the direction the ground is sliding, for example a left step between two left lateral faults, the gap between them comes under tension and sinks, opening space that can rapidly fill with sediment. Pull-apart basins typically take on a rhombic or sigmoidal shape and can subside unusually quickly compared with other kinds of basin, which also makes them attractive targets for oil and gas exploration and locations where mineral deposits and geothermal resources tend to concentrate.