Sequence stratigraphy of the inner Finnmark carbonate platform (Upper Carboniferous-Permian), Barents Sea -: correlation between well 7128/6-1 and the shallow IKU cores

A new set of descriptions has been prepared for five of the IKU cores, a series of shallow stratigraphic cores penetrating the Upper Carboniferous-Permian Finnmark carbonate platform succession near its southern erosional truncation against the Norwegian mainland. These data are compared with core descriptions previously published from the thicker 'stratigraphic reference section' of the exploration well 7128/6-1 (Ehrenberg et al. 1998a), New fusulinid datings from 7128/6-1 are correlated with existing fusulinid data from the IKU cores to provide a consistent time-stratigraphic framework for landward correlation of depositional sequences previously defined in the 7128/6-1 reference section. These correlations reveal a limited two-dimensional image of depositional sequence geometry for the inner platform. Of the 7 major sequences previously defined in the Kasimovian through Upper Permian section of well 7128/6-1, 2 sequences are suggested to pinch out before reaching the IKU cores, while the remaining 5 sequences thin by 32-63% and show landward loss of lithologic resolution of systems tracts. Thinning is probably accomplished by increasing magnitude and frequency of hiatuses both within and bounding each sequence, reflecting gradual uplift of the Norwegian mainland and seaward tilting of the platform throughout the depositional history. Landward changes in lithology, dolomitization, and porosity are relatively subtle, suggesting that platform deposition extended well beyond the present southern termination of carbonate strata.