Figure 1
Map showing the Open Door area (red outline) in Faroese sector. The inserted box outlines the region of the map shown in Fig. 2. (Download the shapefile for the area here)

Maximum closure:
Ymir Ridge: 1750 m
WTR-N: 1200 m
WTR-S: 800 m

Fractured volcanics
Siliciclastic sandstone

Intravolcanic tuffs
Marine shales

Figure 2
Bouguer anomaly gravity map and b) Structural map of the area in question. Both maps are from Ritchie et al. (2011). The black outlined features indicate four-way dip closures in the area along the border to UK, at ‘A-horizon’ level (see Fig. 3). See Fig. 1 for location.

Figure 3
This map shows the predicted depth to the A-horizon in meters. The A-horizon is equivalent to the onshore coal bearing formation which represents the transition between the pre- and syn-breakup volcanism, as identified on seismic data by Petersen et al. (2015). The three four-way dip closures shown on the map are as follows: Ymir Ridge, Wyville Thomson Ridge N (WTR-N) and Wyville Thomson Ridge S (WTR-S). The maximum closure is 1750 m, 1200 and 800 m, respectively. Closures have been mapped on other levels also.

Figure 4
SW-NE orientated seismic profile across the Ymir Ridge and the northern part of Wyville Thomson Ridge. See Fig. 3 for location.

Figure 5
SE-NW-NE orientated seismic profile across well 164/7-1 and the southern part of Wyville Thomson Ridge.

Figure 6
A summary map of all seep data from the Faroese region, based on SAR seep data, air laser fluorescence, seabed cores, well data and outcrops. In the south-western part of the map region, the three largest four-way dip closures in the area, i.e. the Ymir Ridge and the Wyllie-Thompson Ridge north and south, respectively, are shown at A-horizon depth.


  • Petersen, U.K., Brown, R.J. & Andersen, M.S. 2015. Geophysical aspects of basalt geology and indentification of intrabasaltic horizons. In: Eidesgaard, Ó.R. & Ziska, H. (eds.) Faroe Islands Exploration Conference: Proceedings of the 4th Conference., Annales Societatis Scientiarum Færoensis, Supplementum LXIV, 74-93.
  • Ritchie, J.D., Ziska, H., Kimbell, G., Quinn, M. & Chadwick, A. 2011. Structure. In: Ritchie, J.D., Ziska, H., Johnson, H. & Evans, D. (eds.) Keyworth, Nottingham, UK: British Geological Survey and Tórshavn, Faroe Islands: Jarðfeingi,. Keyworth, Nottingham, UK: British Geological Survey and Tórshavn, Faroe Islands: Jarðfeingi, 9–70.