Apart from the rather limited reports on Paleozoic derived oils there are many oils in the North Sea with “atypical” Jurassic fingerprints. Could these be sourced by Paleozoic source rocks, or represent mixtures of Jurassic and Paleozoic derived oils?   In this study a suite of North Sea oils will be analysed geochemically and those with an atypical Jurassic signature will be investigated in further detail to reveal if they may have a Pre-Jurassic origin. It will further be explored if po...