Magmatic dynamics and stratigraphy within the Faroe Islands Basalt Group: Can we correlate basalt?

The ability to correlate within volcanic successions is integral to our understanding of the temporal and spatial evolution of Large Igneous Provinces. It is also important in the exploration for and effective development of energy and hydrological resources within volcanic provinces such as the West of Shetland Basins and the Columbia River Basalt Group. In this study we present new geochemical data for the Faroe Islands Basalt Group (FIBG) that comprises significant onshore exposures of the North Atlantic Igneous Province in a location proximal to the palaeo-rift initiation. All the new data has been integrated within an existing 3D ArcGIS database for the islands. This allows high resolution spatial integration of field profile, biostratigraphic and lava geochemical data via the interpolation of regional inter-lava surfaces. The FIBG contains a number of distinct magma source signatures, which can be separated on geochemical terms alone. By sampling a number of flow by flow transects through target areas of the lava stratigraphy we have been able to resolve the spatial and temporal development of some of these magma types which sheds new light on mantle melting dynamics in the early stages of continental rupture. We present evidence to suggest that a number of these magma types are repeated in space and time. An important finding from the new data is that magma types previously assigned as regionally diagnostic to specific formations have non-differentiable representatives in other formations entirely precluding their use as regional correlation tools. The implications of these findings are that models attempting to explain temporal and spatial evolution of mantle anomalies, such as Iceland, based on spot sampling and published single profiles need to explain these greater complexities. In terms of exploration in the West of Shetland region it must be concluded that geochemical correlation of lava flows may only be useful on a local scale, where a well-defined index well or section is available. These must however, be integrated with a tight geophysical and down hole facies assessment to account for facies distribution variations.