Stratigraphy and structure of the Ringebu - Vinstra district, Gudbrandsdalen; with a short analysis of the western part of the sparagmite region.

Abstract

The Ringebu-Vinstra district, Gudbrandsdalen, is one in which several of the main structural units in Southern Norway come together. Essentially, the rocks belong to three main tectonic units: 1. Parautochthonous rocks of the Hedmark Group of latest Precambrian and Eocambrian age with overlying Cambro-Ordovician deposits. 2. Allochthonous sedimentary rocks, which can be correlated with parts of the Hedmark Group and the Cambro-Ordovician, corresponding to the Kvitvola nappe occurring in Østerdalen and in Engerdalen. 3. Crystalline rocks of the Caledonian overthrust massifs, which in places are overlain by sedimentary rocks - the Jotun nappe. At Feforkampen the crystalline rocks with their cover of sedimentary rocks most probably correspond to the Valdres nappe. The Espedalen massif and the outlier of crystalline rocks in Valsfjell could also belong to the Valdres nappe. The sedimentary rocks from the present district are treated from a lithostratigraphical and petrographical point of view. The structural evolution of the Ringebu-Vinstra district has been complex with four major phases of deformation (D1-D4). The first phase of deformation involved the thrusting of the Jotun nappe-Valdres nappe and the Kvitvola nappe with minor thrusting of the parauthochthonous Vangsås Formation.