A dome in which the overlying rocks have been ruptured by the squeezing out of plastic (malleable) material at the center of the dome.

dome, core, or anticlinal fold of plastic or igneous material which has been squeezed upward to pierce overlying rocks. Common diapirs in sedimentary strata are domes of salt or shale.

a domed rock formation where a core of rock has moved upward and pierced through the more brittle overlying strata

Forceful, upward intrusion of a rock mass into overlying rock. In the case of an igneous diapir, the intruding rock may be magma or a crystal-rich mush, either of which is less dense than the surrounding rock.

A dome or anticlinal fold in which the overlying rocks have been ruptured by the intrusion of salt or other plastic core material.

An intrusion which domes the overlying cover after piercing lower layers. Occasionally diapiric bodies pierce the surface.

an anticlinalfold in which a mobile core, such as salt or gypsum, has pierced through the more brittle overlying rock. [AHDOS

A diapir ( http://www.bartleby.com/61/93/D0199300.html) (French, from Greek diapeirein, to pierce through) is an intrusion caused by buoyancy and pressure differentials. Diapirs may include igneous structures, but are more commonly applied to non-igneous, relatively cold materials, such as salt domes and mud diapirs; diapirism is thought to occur on Enceladus. A diapir is any relatively mobile mass that intrudes into preexisting strata.