The stratigraphy, environment of eruption and age of the Faroes Lava Group, NE Atlantic Ocean

The papers in this volume represent a step forward in our knowledge of the geological evolution of the North Atlantic from the Cretaceous-Palaeogene boundary through to the early Eocene. With the increase in hydrocarbon exploration activities in the Faroe-Shetland Basin (Fig. 1), new interpretations of the regional geology have become increasingly important, and the accuracy of the time frame for this work is vital to our understanding of the sequence of volcanic and sedimentary events. The synthesis of data relating to Palaeogene volcanism and sedimentation along the Norwegian Margin by EIdholm et al. emphasizes the importance of transfer zones, possibly inherited from the Proterozoic basement, in the distribution of sediments and volcanic products during rifting (Fig. 2). Furthermore, subsequent uplift and the development of marginal highs are invoked as factors which affectedwater circulation within the basins, leading to a deterioration in the Eocene climate. This work identifies the relevance of the North Atlantic Igneous Province (NAIP) as an influence on environmental systems on a global scale. Ar-Ar and Pb-U isotopic age data show that the main period of continental flood basalt volcanism in the NAIP extended from c. 60.5 Ma through to c. 54.5 Ma (Table 1). Biostratigraphical analysis of these volcanic-sedimentary sections (Jolley et al. 2002) shows that the onset of this interval equates to the Late Paleocene Thermal Maximum (LPTM). New isotopic dating of the oldest part of the volcanic sequence on the Faroe Islands, the Lower Formation, by Waagsteia et al. has further confirmed the age for the interval around the LPTM (Fig. 3). However, problemsremain with regard to the identification of normal polarity events within these lavas,
recognized as Chrons 25n and 26n. Stratigraphy within the Faroe-Shetland Basin has benefited from the identification of genetic depositional sequences by Ebdonet al. (1995), based on the BP interpretation of geophysical and biostratigraphical information (Fig. 3). This approach subdivides the sediments of the basin into a number of depositional sequences (T10-T60). Palynofloras (Ellis et al.; JoUey et al. 2002) attributable to the upper part of Sequence T40 (Ebdon et al. 1995) are recovered from the exposed Lower Formation of the Faroe Islands, confirming that the two normal polarity events present in the Lower Formation are cryptochrons.