The Lagavulin exploration well 217/15-1Z penetrated a ~2.6 km thick volcanic sequence dominated by extrusive basaltic rocks spanning the Palaeocene-Eocene boundary in the NE Faroe-Shetland Basin (FSB). The well comprises one of the thickest drilled sequences through the North Atlantic Igneous Province. Integrated analysis of drill cuttings and wireline-log data reveals key volcanic lithofacies: i) tabular lava flows; ii) compound lava flows; iii) hyaloclastite; and iv) volcaniclastic rocks. The volcanic facies reveal two major sub-aqueous to sub-aerial sequences consistent with lava delta progradation. These sequences are separated by a volcanic hiatus represented by extensive reddened soils which preceded the re-submergence of the area. Emergence followed by submergence of the first lava delta is interpreted to record an intra-T40 transient uplift event near the Palaeocene-Eocene boundary. Basalts from the lower ~1.3 km have low TiO2 (<1.5 weight %) and low Zr/Y (2- 3), with olivine-phyric picrites towards the base (Mg# 70-82; olivine Fo85-91). The hiatus correlates precisely with a change to high TiO2 (2.5-3.2 weight %) high Zr/Y (>4) compositions which dominate the upper sequence. The associated change in lava geochemistry, transient uplift and volcanic hiatus appears consistent with a transient pulse of hot buoyant plume material passing beneath the area.
Bibliographical noteAcknowledgements and Funding
This work was funded by Chevron. The authors would like to acknowledge the Chevron West of Shetlands team along with the Joint Venture partners OMV, Faroe Petroleum and Indemitsu for access to data along with permission to publish this study. PGS is thanked for access to the Corona Ridge Regional Geostreamer (CRRG) data and permission to publish the seismic line. The paper was improved thanks to insightful reviews by S. M. Jones and A. Saunders, which substantially improved an earlier draft. J. Still and F. Thompson gave invaluable technical support at the University of Aberdeen, and K. Wall helped with real-time cuttings analysis.