Geologiske Undersøkelser i Espedalen. Gradteig Vinstra og tilgrensende høifjell.

Abstract

This paper deals with a group of mountains situated in Espedalen between Vestre Gauldal and Skabu on the map quadrangle F 30 V, Vinstra. The field work was conducted by the author during the summers 1941-42, and -43. This mountain group must be regarded as the fore-land of the Jotunheim massif: it is built up of thrust masses that in a high level of the earth's crust as rather thin nappes have been thrust forward from NW towards SE on the southern side of the Jotunheim syncline. The geological units of the present area are as follows: I. Basal sediments of Cambro-Ordovician age. II. Thrust masses of igneous rocks of the Bergen-Jotun series with their accompaniment of crystalline schists. III. The Valdres sparagmite, which is a Caledonian synorogene or interorogene flysch formation, that has been subjected to thrusting and recrystallization. Essexite dikes in the Espedal: there are two occurrences of unpressed dikes near the southern end of Espedalsvann, from where specimens previously have been gathered by K.O. Bjørlykke and V.M. Goldschmidt. Samples taken by the author place the dikes as Permian essexites of the Oslo region.