Compilation and appraisal of geochronological data from the North Atlantic Igneous Province (NAIP)

The North Atlantic Igneous Province (NAIP), composed of volcanic sequences and intrusive rocks, occurs onshore in Greenland, the Faeroe Islands, the UK and Ireland, and offshore surrounding these areas as well as the west coast of Norway. Geochronological data have been published for Cenozoic igneous and volcanic rocks for much of the province, and provide valuable information to analyse the evolution of the province and magmatic processes more broadly. As part of the NE Atlantic Geosciences (NAG) cooperation, we examined approximately 700 dates from over 70 published studies and created a comprehensive database to facilitate ready access to this important information. This includes U–Pb, Rb–Sr, Re–Os, ⁴⁰Ar/³⁹Ar and K–Ar ages presented relative to the Geological Time Scale 2012. ⁴⁰Ar/³⁹Ar and K–Ar ages have been recalculated to a common reference. The complete database includes data that range from approximately 177 to 0.19 Ma. Our evaluation shows that variable sample quality, ambiguous data-handling methods, inadequate data reporting and data interpretation should preclude the use of data for purposes of rigorous geochronological analysis. Through a series of filtering techniques described here, we suggest excluding >500 dates as being of too poor a quality to use in age determinations. Our analysis highlights the need for published geochronological studies to include sufficient information to allow critical assessment of ages and interpretations. We present an 'optimized' dataset containing 130 ages that range from approximately 64 to 13 Ma. The filtered dataset emphasizes the need for firm chronological benchmarks and suggests that some sub-provinces in the NAIP would greatly benefit from renewed research attention.