The Upper Palaeozoic successton on the Finnmark Platform, Barents Sea TOM BUGGE, GUNN MANGERUD, GEIR ELVEBAKK, ATLE MØK, INGER NILSSON, STEIN FANAVOLL & JORUNN OS VIGRAN Bugge, T., Mangerud, G., Elvebakk, G., Mørk, A., Nilsson, 1., Fanavoll, S. & Vigran, J. 0.: The Uppr Palaeozoic succession on the Finnmark Platform, Barents Sea. Norsk Geologik Tiskri t, Vol. 75, pp. 3-30. Oslo 1995. ISSN 002 9 -196X. During the Late Palaeozoic, sediments were deposited in the proto-Barents Sea along the northem margin of the Fennoscandian Shield. These sediments have no outcrops onshore Norway, but a condensed Upper Palaeozoic succession occurs on the Finnmark Platform dose to the present coast of Norway. During 1987 and 1988, IKU Petroleum Research cored most of the condensed, 600-700 m thick sedimentary section, and except for about 100 m, the entire Carboniferous-Permian succession was cored. Using high resolution multichannel seismic data, fourteen seismic units have been defned in the cored succession. These are grouped into four stratigraphic intervals and discussed in a stratigraphic context based on seismic, sedimentological and biostratigraphic data. The dating is based on palynomorphs in the clastic-dominated Lower Carboniferous succession, by fusulinids in the carbonate-dominated Upper Carboniferous/Lower Permian succession, and by palynomorphs in the clastic-dominated Uppr Permian and lowermost Triassic succession. A major transgession afected the Finnmark Platform in the Early Carboniferous (Visean), and marine shale was deposited in the east, while a local basin in the west was flled by food plain deposits up to 650 m thick. A overall transgressive trend through the ?Bashkirian to Kasimovian (Mid-Late Carboniferous) gave food plain to shoreface deposits on the southem Finnmark Platform. A carbonate platform with signifcant clastic input existed from the Late Carboniferous (Gzhelian) to Late Permian, with Palaeoa pl ysina-phylloid algal buildups forming during the Gzhelian-Asselian and bryozoan buildups during the Sakmarian-Artinskian ( Early Permian). The clastic input increased during the Late Permian, and at the Permian/Triassic transition the carbonate shelf was transgressed and covered by clastic sediments prograding from the east and southeast. T. Bugge, A. Mørk, S. Fanavol, J. O. Vigran, G. Mangerud1, G. Elvebakk2 & l. Nilsson2, !KU Petroleum Research, N-7034 Trondheim, Norway. 'Present address: Norsk Hydro a.s., Research Centre, 5020 Bergen, N orway; 2Saga Petroleum a.s., Torvet, 940 Harstad, Norway. Exploration for oil and gas on the Barents Shelf started in the early 1980s and, to date, 53 deep hydrocarbon exploration wells have been drilled by oil companies. Stimulated by the need for more geological information, a shallow stratigraphic drilling programme was initiated by IKU Petroleum Research in 1984 and up until now 57 stratigraphic drillings (Fig. l ) with continuous coring have given 3700 m core from the Barents Sea. Eleven of these drillings are from the Palaeozoic succession, three from the Svalis Dome and 8 from the Finnmark Plat form (Fig. 2). The present study area is situated ofshore northern Norway, on the eastern part of the Finnmark Platform, which parallels the coastline of the Troms and Finnmark counties. The platform is bounded to the northwest by the Harstad and Tromsø Basins and to the north by the Hammerfest and Nordkapp Basins (Fig. 1). The 'disputed area' between Norway and Russia is adjacent to the east. The eight stratigraphic cores on the Finnmark Platform were drilled before any deep wells were drilled in this area and provide a valuable data 'point' with an almost fully cored succession. They were drilled in ofset positions in order to cover most of the Upper Palaeozoic succession vertically as well as laterally. Being located on the southern part of the platform, the cored succession is condensed and probably has more breaks in deposition compared to the northern, more basinward part of the platform. To date, 13 hydrocarbon exploration wells have been drilled into Palaeozoic rocks on the Barents Shelf, but with the exception of three wells, which are still confdential, these are located outside the Finnmark Platform and have limited coring programmes. The amount of published Palaeozoic data from the Barents Shelf is limited and primarily based on seismic data, some released wells on the Loppa High and on correlations with Bjørnøya/Svalbard and Novaya Zemlya, where Upper Palaeozoic rocks are exposed (e.g., Rønnevik 1981; Faleide et al. 1984; Gram berg et al. 1988; Gerard & Buhrig 1990; Alsgaard 1992; Bruce & Toomey 1992; Cecchi 1992; Nilsen et al. 1992; Nøttvedt et al. 1992a). Some of these publications refer to the shallow stratigraphic drillings, but with the exception of publications by Nilsson (1993), Mangerud (1994) and Stemmerik et al. (in press) little direct documentation or use of the data has so far been published. This article presents the results from the IKU shallow stratigraphic drillings in the Upper Palaeozoic succession on the Finnmark Platform. The Carboniferous to Lower Triassic succession was divided into fourteen seismic units, which are grouped into four main intervals. These four intervals are discussed in a stratigraphic context based on seismic, sedimentological and biostratigraphical data. Regional correlation of each of the units is dis cussed, and implications for palaeogeographic recon struction are included.