Trondhjemite

From Wikipedia, the free encyclopedia
Trondhjemite
Igneous rock
HKU 香港大學 Stephen Hui Geological Museum 許士芬地質博物館 the oldest rocks from China TTG Migmatite Taishan complex n old trondhjemitic gneiss Baijiafen Anshan Oct 2016 Lnv.jpg
Composition
oligoclase, other plagioclase

Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites that occur in the oceanic crust or in ophiolites are usually called plagiogranites.

Trondhjemite is common in Archean terranes occurring in conjunction with tonalite and granodiorite as the TTG (tonalite-trondhjemite-granodiorite) orthogneiss suite.[1] Trondhjemite dikes also commonly form part of the sheeted dike complex of an ophiolite.

The name of the rock type is derived from the city of Trondheim, Norway.

Footnotes[]

References[]

  • Best, Myron G. (2002) Igneous and Metamorphic Petrology, Blackwell Publishing, 2nd ed. ISBN 1-4051-0588-7
  • Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge, UK: Cambridge University Press. pp. 139–143. ISBN 9780521880060.


Retrieved from ""