Morphology and structural, stratigraphic setting of volcanic deposits at Skoll High on the Vøring Plateau

Abstract

The voluminous igneous complexes that are present in the sedimentary basins of the volcanic rifted Vøring Margin have recently gained attention due to their promising potential for carbon sequestration. Although there have been major improvements in the field of intra- and subbasalt imaging and subbasalt sequences over the past decade, the emplacement mechanism, stratigraphical setting, structural setting and postdepositional deformation of these are not fully understood. The work of this thesis has utilized high resolution 3D seismic data, 2D seismic data, and well data to study the volcanic deposits at Skoll High on the outer Vøring Margin with regards to their origin, emplacement, and post-depositional deformation. The results include interpretation of Seaward Dipping Reflectors (SDR’s), landwards flows, lava delta, inner flows, pseudocraters, fissures, subaerial drainage channels, gas or fluid migration structures, bench collapse, and lava delta collapse. Several of these interpretations have been compared to similar field examples from around the world. From these interpretations as well as previous studies, a geological model is proposed, comprising 4 stages: 1 Uplift, intrusions, sill emplacement, and the creation of the Vøring escarpment due to rifting, 2 emplacement of SDR’s, landwards flows, inner flows, and the creation of a lava delta, 3 regression, collapse of lava delta, and pseudocrater formation due to mixing of surface water and lava flows, 4 trangression, erosion of the high, and formation of a widespread drainage network. The storage potential for CO2 sequestration at Skoll High has been calculated as 67,5 Gt worth of CO2, but due to the nature of this calculation, it might only be used as a preliminary estimate. More knowledge about how CO2 behaves when injected into basalts, and further data offering insight into the 3D structure of the basalt sequences is needed to improve this estimate.