Main and trace element content of shales from Ankerskogen (Hamar) and Øvre Slottsgt. (Oslo). Norway

NGU Rapport 2009.063

The composition of black and other shales within the Oslo Rift system may vary locally with respect to main and trace elements. Chemical analysis of major, minor and trace elements of one hundred Cambrian and Ordovician shale samples collected in Oslo and Hamar quantifies the variation in concentrations among the samples. In this report the concentration of elements determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) after digestion in strong acid, combustion assay with infrared detector (i.e. Leco stove), and x-ray fluorescence (XRF), is presented on samples from two locations in the Oslo Rift system. The data are presented in similar diagrams to those used by Broekmans and Sæther (2008) to facilitate comparison between shale samples from different localities. Data on mineralogical composition are assessed with respect to the role of sulfides and carbonates in forming gypsum and thus potentially causing swelling.