Jurassic to Cretaceous stratigraphy of shallow cores on the Møre Basin Margin, Mid-Norway

Abstract

Smelror, M., Jacobsen, T., Rise, L., Skarbo, 0., Verdenius, J. G. & Vigran, J. 0.: Jurassic to Cretaceous stratigraphy of shallow cores on the More Basin Margin, Mid-Norway. Norsk Geologisk Tidsskrift, Vol. 74, pp. 89-107. Oslo 1994. ISSN 0029-196X. Four cores drilled by IKU in summer 1988 southwest of Kristiansund at the More Basin Margin close to the Gossa High ( 6206/02) penetrated marginal marine Lower Jurassic coarse clastic and Upper Cretaceous shelf deposits. The lower part of the eastemmost core 3 contains Lower Jurassic matrix-supported terrestrial conglomerates rich in mafic clasts deposited in an alluvial fan environment. This is succeeded by a clast-supported, partly marine-inftuenced very coarse gneiss conglomerate of Pliensbachian- Toarcian age, possibly representing fan-delta deposits. Core 2 penetrated a similar clast-supported conglomerate below a more sandy, partly marine inftuenced unit of Late Toarcian- Aalenian age. Core 8, further west, and the lower part of core l contained similar sandy successions of Late Toarcian- Aalenian age deposited in a distal fan-delta environment. In the latter core there is a major hiatus (some 80 million years) as Upper Toarcian- Aalenian sediments are overlain by Upper Albian Shelf deposits. The Cretaceous succession in the core contained marine mudstones, sandstones and shales/claystone s of Late Albian to Turonian/Santoni an ages. Distinct seismic reftections are present in the cored succession, but only those in the Cretaceous sequence can confidently be tied directly to the More Basin based on the available data. A bedrock map of the More Basin Margin is presented.