The lower Kapp Duner Formation on Bjornoya consists of two Palaeoaplysina buildup complexes separated by a karst surface, believed to represent a third order sequence boundary. The buildup complexes are composed of 3-10 m-thick, stacked, shallowing upward cycles of restricted shelf wackestone and Palaeoaplysina wackestone and packstone. Each cycle is terminated by an event of subaerial exposure related to fourth order fluctuations in sea level. The upper complex passes laterally into restricted shelf wackestone and mudstone facies. Diagenesis started with early dolomite replacement of carbonate mud, dissolution of aragonitic material, and precipitation of anhydrite cement in secondary pores. These took place in an arid climate during repeated subaerial exposure related to fourth order fluctuation in sea level, and were associated with evaporite sedimentation in the adjacent basin. They were followed by dolomite replacement of anhydrite and precipitation of limpid dolomite rhombs and ankeritic dolomite. These processes are related to prolonged subaerial exposure in a more humid climate during the middle and Late Permian. Post-Permian diagenesis involved minor quartz and calcite cementation.

Seismically identified mounds in the Early Permian succession of the offshore areas of the Barents Sea were probably not subjected to prolonged middle and Late Permian exposure. Their porosity development was controlled mainly by early, intra-depositional processes, and they are predicted to form potential but highly heterogeneous reservoirs with porosities in the range of 10-20%.

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