The form of the Fongen-Hyllingen gabbro complex, Trondheim Region, Norway

The Fangen-Hyllingen gabbro complex is a large layered body in the Trondheim Region of the Norwegian Caledonides. Primary igneous rocks vary from ultramafics to olivine gabbros, gabbros and norites, diorites and felsic differentiates. A contact aureole is preserlt with well developed cordierite, sillimanite and andalusite zones, all zones additionally containing garnet. The body had an original bowl-shape, possibly with a feeder, and rhythmic layering in a saucer-like disposition. The complex and its envelope have been penetratively deformed in large areas and at a later stage the gabbro has been tilted downwards to the east and folded in its northern part. During regional metamorphism much of the complex became overprinted to give hornblende metagabbro and, where deformed, foliated amphibolites.