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The Janusfjellet Subgroup (Bathonian to Hauterivian) on central Spitsbergen: a revised lithostratigraphy |
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| Authors: | H DYPVIK T A EIKELAND K BACKER-OWE A ANDRESEN H JOHANEN A ELVERHØI J NAGY P HAREMO T BIÆRKE |
| Institution: | H. Dypvik, J. Nagy, T.A. Eikeland, K. Backer-Owe, A. Andresen, and A. Elverhøi, Department of Geology, University of Oslo, P. O. Box 1047 Blindern, N-0316 Oslo 3, Norway;P. Haremo, Norsk Hydro A/S, P.O. Box 200, N-1321 Stabekk, Norway;T. Bjwrke, Storgata 47, 3290 Stavern;H. Johansen, Norsk Polarinstitutt, Rolfstangveien 12, Snarøya, P. O. Box 158, N-1330 Oslo lufthavn, Norway. |
| Abstract: | The Janusfjellet Subgroup is a marine shelf to prodeltaic succession dominated by shales with subordinate siltstones and sandstones. The subgroup comprises a lower Agardhf jellet (Upper Bathonian - Berriasian) and an upper Rurikf jellet (Berriasian - Hauterivian) formation. Based on field work in central Spitsbergen the following subdivisions of the formations are proposed (units listed in ascending order). The Agardhf jellet Formation (up to 290 m thick) contains four members: Oppdalen - a fining upwards succession from conglomerates to shales; Lardyfjellet - black paper shales; Oppdalsata - grey shales with siltstones and sandstones; and Slottsmøya - grey shales and black paper shales. Within the Oppdalen Member three beds are recognised: Brentskardhaugen - phosphoritic conglomerate; Marhøgda - glauconitic sandstones', and Drønbreen - siltstones and shales. The Rurikfjellet Formation (thickness up to 226 m) is composed of two members: Wimanfjellet - grey and partly silty shale sequence, containing the Myklegardfjellet Bed (of plastic clays) at its base; and Ullaberget - silty and sandy shales with siltstones and sandstones. |
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