Pyroclastic shield

In volcanology, a pyroclastic shield or ignimbrite shield is an uncommon type of shield volcano. Unlike most shield volcanoes, pyroclastic shields are formed mostly of pyroclastic and highly explosive eruptions rather than relatively fluid basaltic lava issuing from vents or fissures on the surface of the volcano.[1] They typically display low-angle flank slopes and often have a central caldera caused by large eruptions. Lava is commonly extruded after explosive activity has ended. The paucity of associated Plinian fall deposits indicates that pyroclastic shields are characterized by low Plinian columns.

Pyroclastic shields are commonly known to form in the Central Andes of South America, as well as in Melanesia (the island of Bougainville alone has two). There are also pyroclastic shields in Africa, such as Emi Koussi in Chad.

Examples

See also

Categories:

  • Pyroclastic cones

References

  1. "Global Volcanism Program | Educational Resources | Types and Processes Gallery | Shield Volcanoes". Volcano.si.edu. Retrieved 2012-12-24.
  2. Schmincke, H.-U; Sumita, M (1998). "Volcanic evolution of Gran Canaria reconstructed from apron sediments: synthesis of VICAP project drilling". Proceedings of the Ocean Drilling Program, 157 Scientific Results. Proceedings of the Ocean Drilling Program. 157. CiteSeerX 10.1.1.488.3644. doi:10.2973/odp.proc.sr.157.135.1998.
  3. Troll, Valentin R.; Carracedo, Juan Carlos (2016-05-26). The Geology of the Canary Islands. ISBN 9780128096642.
  4. "Global Volcanism Program | Santa Isabel". volcano.si.edu. Retrieved 2018-06-13.


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