Low-grade sediments on Precambrian gneiss in Vanna, Troms, Northern Norway

Abstract

Forkortet: Presumed Precambrian, quartzo-feldspathic gneisses on Vanna, northern Norway, are overlain by two formations of arkosic sandstone and siltstone, the Tinn- vatn and Bukkheia formations. The gneiss\/sedimentary sequence boundary is an undulating primary unconformity. Bedforms and sedimentary structures suggest that the two formations are fluviatile-deltaic and shallow-marine, respectively Diorite sheets intrude the upper formation. The sedimentary sequence is slightly metamorphosed and has been affected by at least three deformation episodes. Its age is discussed.