Gabbrokonglomeratet i Sjodalen.

Abstract

The Gabbor Conglomerate in Sjodalen. The area dealt with in the present paper is a part of the valley of the river Sjoa (Sjodalen) in central southern Norway, about 61o42'N and 9o18'E. An account of the general geology of the region is found in Strand 1951, the geologic map in that paper needs correction for the area here in question from the data presented in this paper. The Gabbro Conglomerate outcropping along Sjoa is a memger of the Valdres Sparagmite. It contains highly deformed boulders of a light meta- trondhjemitic rock (Fig. 1). The matrix of the conglomerate is most commonly a greenish schistose rock (Tables 1-3). The analysis table 1 shows a rock of a nearly gabbroid composition, while the analysis table 2 shows unquestion- ably a sedimentary rock with a large admixture of gabbroid material. Table 3 gives mineral compositions, estimated from slides, of four further rocks. Here Nos 4 and 5 are pelitic rocks with an admixture of gabbroid material, while the rock No. 6 rends towards a plagioclase arkose. The mountain, the geology of which is illustrated on the stereogram Fig. 2 is the south-west limb of a syncline (or synclinorium) with axis trending NW-SE and pitching SE. The south-east axial pitch causes the tectonically higher rocks to occur in the south-east part of the mountain.