Organic geochemistry of upper palaeozoic lacustrine shales in the East Greenland basin

The Devonian and Carboniferous-Lower Permian succession in East Greenland includes three geochemically distinct groups of lacustrine shales with a possible petroleum potential: 1. 1. Source rocks with 2-10% TOC, Hydrogen Index betwen 450 and 900, a high content of saturated hydrocarbons, a high content of n-alkanes extending into the waxy range and a distinct odd/even predominance and low to moderate Pr/Ph values occur in the Upper Carboniferous part of the succession. 2. 2. Source rocks with ∼ 10% TOC, Hydrogen Index above 700, a high content of saturated hydrocarbons, a complete dominance of n-alkanes without odd/even predominance, low waxiness and virtual lack of isoprenoids appear to be restricted to the Upper Devonian. 3. 3. Shales with a high content of saturated hydrocarbons, higher contents of branched and cyclic compounds, high Pr/Ph values, low waxiness and max of n-alkanes at C₂₂ occur in the Middle Devonian.