Open AccessAcid and intermediate intrusions, deformation and gneiss formation, north-east of Fiskenæsset
Author(s) -
John S. Myers
Publication year - 1976
Publication title -
rapport
Language(s) - English
Resource type - Journals
eISSN - 2597-2944
pISSN - 0418-6559
DOI - 10.34194/rapggu.v73.7414
Subject(s) - geology , gneiss , geochemistry , sill , anorthosite , biotite , gabbro , igneous rock , sillimanite , dalradian , layered intrusion , metamorphic rock , mafic , petrology , quartz , plagioclase , paleontology
The sequence of acid and intermediate intrusions and of deformation provides the chronological framework of the geology of an area of 500 km2 north of inner Fiskenæsfjorden and around inner Grædefjord (Plate 1). The oldest recognisable rocks are amphibolites and ultramafite derived from volcanics, irregular doleritic intrusions and layered, gravity-stratified sills; metasediments, chiefly quartz+ biotite±garnet±sillimanite±magnetite gneisses; and layered, gravity-stratified bodies of anorthosite, leucogabbro and gabbro. These rocks were already partly deformed before the sequence of acid and intermediate igneous intrusions and deformation described below and summarised in Table 1.