Facies and seismic analysis of the Late Carboniferous Early Permian Finnmark carbonate platform (southern Norwegian Barents Sea): An assessment of the carbonate factories and depositional geometries

摘要

The late Palaeozoic buried Finnmark platform, in the Norwegian Barents Sea, is a depositional system which developed under major modifications of palaeoclimatic and palaeoceanographic conditions, given by the northward drifting of the Arctic depositional domain beyond the tropical belt, the activity of the Gondwanan icecaps, and the gradual closure of the Eastern European seaway. In this study, detailed core/microfacies analysis from the explorations wells 7128/4-1 and 7128/6-1, combined with new 2D seismic sections and available dataset from previous studies in the eastern Finnmark area, have allowed a re-evaluation of the depositional scenarios associated with the Orn and Isbjorn/Polarrev Formations. The late Asselian early Sakmarian depositional record of the Orn Formation, followed by the middle Sakmarian transition to the Isbjorn/Polarrev Formations, shows depth-related variations in sedimentation modes and a change of the platform morphology.