dome

A geologic feature that is the reverse of a basin. It consists of anticlinally folded rocks that dip in all directions from a central high point, resembling an inverted but usually irregular cup.

Such structural domes are the result of pressure acting upward from below to produce an uplifted portion of the crust. Domes are often formed by the upwelling of plastic materials such as salt or magma. The salt domes along the North American Gulf Coast were produced by upwelling ancient sea salt deposits, while the Black Hills of South Dakota are the result of structural domes pushed up by intruding igneous masses.