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.


Further reading