Stratigraphic overview of Palaeogene tuffs in the Faroe–Shetland Basin, NE Atlantic Margin

Abstract

Tuffs form key stratigraphic markers that assist with determining the timing of volcanic margin development. A number of laterally extensive tuffs are preserved along the North Atlantic Margin in the offshore Faroe–Shetland Basin (FSB), a product of early Palaeogene volcanism associated with the break-up and seafloor spreading between Greenland and NW Europe. These tuffs, which are dominantly basaltic in composition, are widely preserved in the contiguous North Sea Basin. However, less attention has been paid to them in the FSB. This study integrates multiple regional datasets, including 3D seismic data and released commercial well logs, to detail the character and distribution of early Palaeogene tuffs in the FSB. The earliest tuffs are more locally identified by their presence in core, whereas later tuffs are more regionally recognizable, highlighting more widespread volcanism with time. The distribution of tuffs also reveals the timing of formation of the previously enigmatic volcanic centres. Importantly, owing to constraints of vertical resolution in well data, we argue that the number of tuffs in the North Atlantic Margin is probably underestimated, and biased towards basaltic tuffs, which are easier to identify on well logs.