This data set reports on the methodologies and results of geochemical analysis carried out on samples of magmatic rock, calcite and sedimentary rocks of Hovedoya Island, Oslo fjord, Norway, in the framework of the publication by Poppe et al. (2020; Geochemistry, Geophysics, Geosystems; https://doi.org/10.1029/2019GC008685). The major and trace element bulk sample geochemical analysis was carried at the Laboratoire G-Time, Université Libre de Bruxelles, Brussels (V. Debaille), the micro-XRF mapping and line scanning, was carried out at the laboratory of the Analytical and Environmental ...