Tectonic features of an area N.E. of Hegra, Nord-Trøndelag, and their regional significance - preliminary notes.

Abstract

Following brief notes on the low-grade metasediments occuring in the area near Hegra, 50 km east of Trondheim, the types of structures associated with three episodes of deformation of main Caledonian (Silurian) age are described. An outline of the suggested major structural picture is then presented. In this the principal structure is seen as WNW-directed fold-nappe developed from the inverted western limb of the central Stjørdalen Anticline. A major eastward closing synclines underlines this nappe-like structure. These initial structures were then deformed by at least two further folding episodes. In conclusion, comparisons are noted between the ultimate fold pattern, the suggested evolution of these folds and H. Ramberg's experimentally produced orogenic structures.