Aspects of the Cenozoic deformational history of the Northeast Faroe–Shetland Basin, Wyville–Thomson Ridge and Hatton Bank areas

Abstract

The nature and age of the Cenozoic compressional/transpressional deformation within the NE Faroe–Shetland Basin, the Wyville–Thomson Ridge and Hatton Bank areas have been investigated, primarily using seismic reflection data. In all three areas, the folds reach approximately 2 to 4k min amplitude and 40k min wavelength. Early and mid-Eocene compressional/transpressional deformation affected the Hatton Bank and Wyville–Thomson Ridge areas, and folding was locally active even earlier, during Paleocene/Cretaceous times. However, the main Cenozoic compressional/transpressional tectonism that affected the Hatton Bank area was coeval with development of the regional Late Eocene Unconformity (C30), and with changes in spreading geometries and a phase of accelerated subsidence in the Rockall Basin. Within the NE Atlantic margin, WNW-to NW-trending lineaments/transfer zones and associated oceanic fracture zones facilitate significant structural segmentation. Offsets in the continent–ocean boundary along Hatton Bank probably reflect inherited basin architecture, and many Cenozoic folds in the Hatton Bank, Wyville–Thomson Ridge and NE Faroe–Shetland Basin areas are considered to mainly reflect compressional buttressing against pre-existing structures. However, relatively small lateral displacements probably occurred along some reactivated transfer zones following continental break-up. Paleocene–Eocene compressional/transpressional deformation may have affected parts of the Faroe–Shetland Basin, but seismic resolution of this is largely masked by pervasive polygonal faulting. Significant, early to mid-Miocene compressional/transpressional deformation is recorded in the NE Faroe–Shetland Basin, and may also have exerted a major influence on the Wyville–Thomson Ridge and surrounding area. In particular, mid-Miocene growth of the Faroe Bank Channel syncline may have resulted in major changes in northern hemisphere deep-ocean circulation with associated impact on global climate. Compressional/transpressional deformation appears to have continued into Pliocene– ?Recent times and resulted in the development of features such as the Pilot Whale Anticline and associated mud volcanoes/diapirs.