Die Gesteine der Halbinsel Strand. Beiträge zur Metamorphose und zum Aufbau der kambro-silurischen Gesteine des Stavanger-Gebietes II

Abstract

This second report of investigations in the Stavanger district gives a description of the geology, and the structural deformations in a cambro-Silurian rock sequence of metamorphosed argillaceous sediments, sandstone, pyroclastics, and a granitic sill in the Strand area, southwestern Norway. With the exeption of this Caledonian sill the whole Cambro-Ordovician series has been transformed into a homogenous unit by the Caledonian deformation. Two systems of fold axes and related linear elements of different age have been recognized. Angles between the older and younger axes fluctuate from 40 degrees to 90 degrees. The same phases of deformation have been recognized in the Precambrian granites and gneisses forming the basement to the Cambro-Silurian beds, whereas movements of Caledonian origin in the deeper situated Precambrian rocks are represented only by narrow fault zones with associated strong nylonitization. The sub-Cambrian peneplain shows an extensive deformation parallel to the main Caledonian tectonic direction. Quartz petrofabrices of the Precambrian granitic gneisses and the Cambro-Silurian sediments show identical patterns and trends.