Metavolcanic rock

Metavolcanic rock is volcanic rock that shows signs of having experienced metamorphism.[1] In other words, the rock was originally produced by a volcano, either as lava or tephra. The rock was then subjected to high pressure, high temperature or both, for example by burial under younger rocks, causing the original volcanic rock to recrystallize. Metavolcanic rocks are sometimes described informally as metavolcanics.[2]

Metavolcanic rock (a metabasalt) from Michigan, US

When it is possible to determine the original volcanic rock type from the properties of the metavolcanic rock (particularly if the degree of metamorphism is slight), the rock is more precisely named by appylying the prefix meta- to the original rock type. For example, a weakly metamorphosed basalt would be described as a metabasalt, or a weakly metamorphosed tuff as a metatuff.[3]

Metavolcanic rock is commonly found in greenstone belts.[4]

See alsoEdit


  1. ^ "Geologic units containing Metavolcanic rock". United States Geological Survey. Retrieved 2018-06-17.
  2. ^ Jackson, Julia A., ed. (1997). "metavolcanics". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN 0922152349.
  3. ^ Schmid, R.; Fettes, D.; Harte, B.; Davis, E.; Desmons, J. (2007). "How to name a metamorphic rock.". Metamorphic Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Metamorphic Rocks (PDF). Cambridge: Cambridge University Press. pp. 3–15. Retrieved 28 February 2021.
  4. ^ Kearey, P.; Klepeis, K.A.; Vine, F.J. (2009). Global tectonics (3rd ed.). Oxford: Wiley-Blackwell. p. 350. ISBN 9781405107778.