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Igneous rock
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.[1] Trondhjemites that occur in the oceanic crust or in ophiolites are usually called plagiogranites.[2][3]

Trondhjemite is common in Archean terranes occurring in conjunction with tonalite and granodiorite as the TTG (tonalite–trondhjemite–granodiorite) orthogneiss suite.[4] Trondhjemite dikes also commonly form part of the sheeted dike complex of an ophiolite.[3]

The rock type was first described by V.M. Goldschmidt in 1916. The name of the rock type is derived from the city of Trondheim, Norway.[1]


  1. ^ a b Jackson 1997, "trondjhemite".
  2. ^ Jackson 1997, "plagiogranite".
  3. ^ a b Philpotts & Ague 2009, pp. 367, 372.
  4. ^ Philpotts & Ague 2009, p. 398.


  • Jackson, Julia A., ed. (1997). "Friable". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN 0922152349.
  • Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge, UK: Cambridge University Press. ISBN 9780521880060.

Further reading[edit]

  • Best, Myron G. (2002) Igneous and Metamorphic Petrology, Blackwell Publishing, 2nd ed. ISBN 1-4051-0588-7