Náttúra og -tilfeingi
Glyvursnes – Vestmanna Seismic Tie.
Fróðskaparsetur Føroya (NVD)
Stuðul úr Granskingargrunninum:
Hilmar Simonsen’s PhD project at the University of the Faroe Islands (UFI), entitled Data Processing and Geological Interpretation of Glyvursnes-Vestmanna Land-and-Marine Seismic Profile, is part of a larger overall project called the Glyvursnes-Vestmanna Seismic Tie, or GlyVeST for short, comprising a geophysical and geological study along a corridor from Vestmanna to Glyvursnes on Streymoy, and in adjoining parts of the Faroes region, particularly southward toward Suðuroy. This zone is particularly appropriate for detailed study in view of the well-surveyed locations at both Glyvursnes and Vestmanna, where there are logged boreholes and additional surface seismic data. These results indicate, among other things, a large change in the thickness of the Middle Basalt Formation of the Faroe Islands – from about 1050 m at Glyvursnes to about 1400 m at Vestmanna. A detailed land-and-marine seismic survey along this profile will answer some very intriguing questions as to the nature of this thickness change and the tectonic (geological) history of the Faroes region. It will help to answer questions about the relative roles of volcanism and sedimentation in this region, important to the understanding of the petroleum potential of the Faroes region.
A line from Vestmanna to Glyvursnes closely follows the west coast of Streymoy, giving us the rare opportunity of correlating continuously between these two points with both onshore and offshore seismic profiles. Although marine data acquisition is easier, the addition of the land line would enable us to investigate in greater detail the seismic properties of the underlying rocks – basalts and sediments – and would give us greater velocity control, which is emerging as a crucial factor in subbasalt seismic imaging. We have already seen at Glyvursnes that a combination of airgun (marine) sources and geophone (land) receivers gave better data than either airgun-streamer or dynamite-geophone combinations. The overall project, GlyVeST, has four principal investigators: Prof. R.J. (Jim) Brown (UFI, project manager), Prof. Morten S. Andersen (GEUS, Copenhagen), Prof. R.S. (Bob) White (University of Cambridge, UK) and Uni K. Petersen (Jarðfeingi, Tórshavn). The objectives of Hilmar Simonsen’s PhD project comprise the more geological aspects of the overall project. These include processing and interpreting the continuous seismic profiles, essentially marine-seismic images but incorporating also land data, between Vestmanna and Glyvursnes, and to map the Middle Basalt Formation of the Faroe Islands. If successful, this would be the first example known to us of marine seismic imaging of a constrained intrabasaltic stratigraphic surface. Further objectives include confirming – or indeed disproving – the large change in the thickness of the Middle Basalt Formation between Glyvursnes and Vestmanna, clarifying the nature of the thickness change, relating this to the tectonic history of the area and, if sufficient borehole data is available, to reconstruct the temperature history of this volcanic sedimentary basin.
Financial support for the strictly research costs for this project have been applied for from Sindri (http://www.sindri.fo), a group comprised of companies holding Faroese petroleum licences. Financing for a second PhD student working in the overall project is already in hand, financed by NVD.