Geochronology of the Faroe Islands: A case study on 40Ar/39Ar dating of local basaltic sills and selected lavas

Published: 2 March 2023| Version 5 | DOI: 10.17632/87gtjjh5gb.5
Jogvan Hansen,


The analytical data presented in this ‘Supplement A' are linked to the geochronological study: “On the timing and nature of magmatism in the North Atlantic Igneous Province: New implications from basaltic rocks of the Faroe Islands” by Jógvan Hansen and Morgan Ganerød, 2023. In the actual work new absolute/radiometric ages for onshore sill intrusions and selected lava flows cropping out in the Faroe Islands, by means of the K-Ar based 40Ar/39Ar incremental heating method, have been determined. As the actual sills quite likely represent the final stages of the waning magmatism in the Faroe Iceland Basalt Group (FIBG) following the large magma outpourings associated with the onset of seafloor-spreading within this part of the NE Atlantic area at ~55.5 to ~56 Ma. Percentages of radiogenic 40Ar and K/Ca ratios have been contrasted against cumulative % 39Ar release for the various incremental heating steps, associated with analyses of Faroese basaltic rock samples used in the actual research project (10 specimens altogether), are presented as diagrams in this supplement (Fig. A). Isochrons representing the various analyse steps during the incremental heating analyses are illustrated as 39Ar/40Ar ratios versus 36Ar/40Ar ratios plots in this Supplement (Fig. B).


Steps to reproduce

The workflow utilised in this project is as follows: Completely fresh basaltic samples were collected from the targeted rock suites; fine rock powder and thin sections were produced for each of the collected samples; all samples were carefully evaluated by means of thin sections and microscope in order to ensure first class quality; samples were irradiated and then analysed on suitable apparatus; analytical results were carefully evaluated and interpreted using (amongst other means) an 'Age Monster' at Norges Geologiske Undersokelse (NGU), Trondheim, Norway; selected/accepted analytical results were tabulated and associated diagrams produced; electronic supplement published (Mendeley); peer-reviewed paper (main manuscript of Hansen and Ganerod, 2023) published.


Geology, Igneous Petrology, Geochronology, Lithosphericstresses, Plate Tectonics, Magmatism