Forced folding and complex overburden deformation associated with magmatic intrusion in the Vøring Basin, offshore Norway

Kamaldeen Olakunle Omosanya, Ståle E. Johansen, Ovie Emmanuel Eruteya, Nicolas Waldmann

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, three-dimensional seismic reflection and borehole data from the Vøring Basin, offshore Norway have been used to characterize a supra-sill related forced fold to understand its evolution and relevance in the context of regional tectonics. Magmatic sills were recognised to be positive high-amplitude anomalies with similar polarity to the seabed reflection. The seismic dataset reveals two groups of sills in the study area comprising interconnected sills beneath the regional forced fold, and those intruded into the overburden. Magmatic sills forming the interconnected sill complex are emplaced at a depth of about 5.5 s TWTT below the modern seafloor. Aspect ratio (length/width), A for the sills ranges from 1.63–6.90. The regional forced fold is interpreted based on its bathymetric and seismic-stratigraphic expression on horizon H7, which is part of the Palaeocene to Eocene Tang Formation. Amplitude of the accommodation fold is about 780 km2. Hydrothermal vent complexes and fluid-flow conduits in the study area develop above the sill edges and on the flanks of the interconnected sill complex extending from the lower part of the Tang Formation to the uppermost section of the Brygge Formation evidencing vertically focussed fluid flow in the study area. The overlying overburden is in turn deformed and structurally compartmentalized through forced folding and Late Cenozoic tectonics. We demonstrate that accommodation folding is formed in response to the emplacement of several interconnected sills during the opening of the Norwegian-Greenland Seas. Sill emplacement in the study area causes uplift of the Cretaceous to Palaeocene depocentre prior to further restructuration during Cenozoic tectonic inversion. Magmatic intrusions documented in this study have wider implications for understanding supra-sill deformations along volcanic margins with well-developed emplaced sills at depth and likewise hydrocarbon prospectivity in the study area.

Original languageEnglish
Pages (from-to)14-34
Number of pages21
JournalTectonophysics
Volume706-707
DOIs
StatePublished - 5 Jun 2017

Bibliographical note

Funding Information:
This work was sponsored by the ARCEx project (Research Centre for Arctic Petroleum Exploration) which is funded by the Research Council of Norway (grant number 228107) together with 10 academic and 9 industry partners. We also acknowledge the Norwegian Petroleum Directorate (NPD) for graciously granting access to the borehole data used in this research and Schlumberger for provision of Petrel? and Petrel ready project for seismic interpretation. Ovie Emmanuel Eruteya is grateful to the Graduate Study Authority, University of Haifa for funding his PhD research and Marie Curie Career Integration Grant FP7-PEOPLE-2011-CIG under the framework of N. Waldmann's GASTIME Project for funding his visit to NTNU. Craig Magee and John Cosgrove are thanked for their outstanding and constructive reviews. We are also grateful to the editor, Philippe Agard for his contributions during the review process.

Publisher Copyright:
© 2017 Elsevier B.V.

Keywords

  • Forced fold
  • Hydrocarbon exploration
  • Inversion
  • Naglfar Dome
  • Sills
  • Vøring Basin

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

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