Geological investigations in the Snåsa-Lurudal area, Nord-Trøndelag.

Abstract

Metasediments and meta-volcanic rocks of supposed Middle Ordovician age overlying a basement complex consisting predominantly of granite-gneisses, are described from an area near the north-eastern end of the lake Snåsavatn. A generalised succession (in ascending order) of mica schists, phylite, limestone and greenstones with greenschist and pyroclastics has been recognized. Observations of the basement gneisses and their relation to the mica schists indicate that while a local concordance of banding is common, on a regional scale a very slight discordance would appear to exist, the various evidence favouring this as being a primary feature. A tripartite division of the main Caledonian deformation is recognisable and the various minor structures are briefly described. Minor folds of the second generation are found to be of considerable value in positioning the axial plane traces of associated major folds.