Uran i kambrisk alunskifer i Oslofeltet og tilgrensende områder.

Abstract

Investigations of the black Alum shales in the Oslo Region initiated the systematical prospecting for uranium in Norway. The Alum shales is a black shale formation in the Cambrian system in Southern Norway. The outcrops of Alum shales in different districts within the Oslo Region are shown on the mao (fig. 1) and the stratigraphy of the formation in fig. 2.In the south, the Cambrian shales lie flat on the Precambrian. Towards north it is an increasing folding and faulting. Field investigations were carried out by Land-Rover with mounted Geiger-M\u00CFller counter. For detailed investigations and sampling Geiger-M\u00CFller and Scintillation counters were used. Fig. 3-4 show the geology and registered radioactivity in two different areas in the Oslo Region. The Upper Cambrian zones 2c-2d have the highest radioactivity in the whole Oslo Region. The content of uranium in these zones is 50-100 g\/ton with maximum 170 g\/ton in thin layers.