Seep carbonate formation controlled by hydrothermal vent complexes: a case study from the Voring Basin, the Norwegian Sea

Several hundred hydrothermal vent complexes were formed in the Voring Basin as a consequence of magmatic sill emplacement in the late Palaeocene. The 6607/12-1 exploration well was drilled through a 220-m-thick sequence of Eocene-Miocene diatomites with carbonate nodules above the apex of one of these vent complexes. Analysed calcites and dolomites from this interval have isotopic signatures typical for methane seep carbonates, with low delta(13)C signatures of -28 to -54parts per thousand PDB. The data suggest that the vent complex acted as a fluid migration pathway for about 50x10(6) years after its formation, leading to near-surface microbial activity and seep carbonate formation.