Diatreme
A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe associated with a gaseous explosion. When magma rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated water vapor and volcanic gases can cause a series of explosions. A relatively shallow crater (known as a maar) is left, and a rock-filled fracture (the actual diatreme) in the crust. Where diatremes breach the surface they produce a steep, inverted cone shape.
Etymology and Geology
The word comes from
Global distribution
Maar-diatreme volcanoes are not uncommon, reported as the second most common type of volcano on continents and islands. At the surface they may be hard to recognise if shallow and dry or eroded and can be up to 3 kilometres (1.9 mi) wide, but are often much smaller.[3][4]
Igneous extrusions cause the formation of a diatreme only in the specific setting where groundwater exists; thus most igneous intrusions do not produce diatremes as they do not reach the surface so as to become extrusions, and further do not also intercept significant amount of groundwater when they become extrusions.
Examples of diatremes include the Blackfoot diatreme and Cross diatreme in British Columbia, Canada.
Economic importance
Diatremes are sometimes associated with deposition of economically significant mineral deposits such as
References
- ^ McGetchin, T. R. (1968). "The Moses Rock Dike: Geology, Petrology and Mode of Emplacement of a Kimberlite-Bearing Breccia Dike, San Juan County, Utah". Ph.D. Dissertation. California Institute of Technology. Retrieved 14 June 2019.
- ^ ISSN 0377-0273.
- S2CID 128423499.
- .
- Kimberlite Emplacement Models Archived 2014-02-18 at the Wayback Machine
- Gannon, Megan, Maar-Diatreme Volcano Research May Help Geologists Predict Eruptions, Find Diamonds, Huffington Post, Posted: 10/07/2012
- Kimberlite Diatremes, Colorado Geological Survey, 10-17-2012
- Lorenz, Volker, Maar-Diatreme Volcanoes, their Formation, and their Setting in Hard-rock or Soft-rock Environments, Geolines, v. 15, 2003, pp. 72-83 Archived 2012-01-30 at the Wayback Machine