Information AboutDiapir |
| CATEGORIES ABOUT DIAPIR | |
| economic geology | |
| structural geology | |
| geological processes | |
| structure of the earth | |
| SHOPPER'S DELIGHT | |
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A diapir () (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 Dome s and mud diapirs. A diapir is any relatively mobile mass that intrudes into preexisting strata. Diapirs commonly intrude vertically upward along fractures or zones of structural weakness through more Dense overlying rocks because of Density contrast between a less dense, lower rock mass and overlying denser rocks. The density contrast manifests as a force of Buoyancy . The process is known as ''diapirism''. The resulting structures are also referred to as ''piercement structures''. In the process, segments of the existing strata can be disconnected and pushed upwards. While moving higher, they retain much of their original properties such as pressure, which can be significantly different than that of the shallower strata they get pushed into. Such overpressured ''Floaters'' pose a significant risk when trying to Drill through them. Rock types such as Evaporitic salt deposits, and gas charged muds are potential sources of diapirs. Diaprirs also form in the Earth's Mantle when a sufficient mass of hot, less dense magma assembles. Diapirism in the mantle is thought to be associated with the development of Large Igneous Province s and some Mantle Plume s. Explosive, hot Volatile rich Magma or volcanic eruptions are referred to generally as Diatreme s. Diatremes are not usually associated with diapirs, as they are small-volume magmas which ascend by volatile plumes, not by density contrast with the surrounding mantle. Economic importance of diapirs Diapirs or piercement structures are structures resulting from the penetration of overlaying material. By pushing upward and piercing overlying rock layers, diapirs can form Anticline s, Salt Dome s and other structures capable of trapping Petroleum and Natural Gas . Igneous intrusions themselves are typically too hot to allow the preservation of preexisting Hydrocarbon s. SEE ALSO |