Seismic Volcanostratigraphy of the Faroe-Shetland Basin

Abstract

The Faroe-Shetland Basin, located in the North Atlantic Ocean, is well known for its complex geological history, with a significant volcanic and tectonic influence shaping its subsurface architecture. The Paleocene continental breakup in the North Atlantic was accompanied by cataclysmic volumes of flood basalt eruption, followed by regional scale intrusion of igneous bodies. The resulting volcanic deposits in the Faroe-Shetland basin hold the key to understand the evolution of a volcanic rifted basin. The thesis presents a comprehensive study of the Paleocene-Eocene volcanic succession using the concepts from seismic volcanostratigraphy to shed light on the paleodepositional environment of different volcanic and volcaniclastic deposits. We use high resolution 3D seismic cubes to classify and interpret different seismic facies, integrated with well log analysis to capture the variations in the physical properties of the intrabasalt units. Our results show the development of a NE prograding lava fed delta system in the central Corona basin during early Paleocene, which is followed by thick deposition of subaerial simple and compound lava flows. We also map the regional Top Basalt reflector and perform RGB spectral blending to delineate different kinds of flow morphologies exhibited by the compound subaerial lava flow during the final stages of flood basalt volcanism in the Brynhild basin. We identify late stage igneous intrusion related gas escape features in the Judd basin that are manifested as narrow vertical zones of amplitude blanking in the seismic data, known as ’seismic chimneys’. We use multi-attribute analysis of the seismic data in order to characterize the 3D geometry, size and fluid flow within in the chimneys.