Major depositional phases of subsidence and basin fill occurred in northern East Greenland during the latest Devonian–earliest Carboniferous, Late Carboniferous, Late Permian–earliest Triassic, mid-Jurassic-earliest Cretaceous, and mid-Cretaceous, and a total of 5-6 km of sediment accumulated. These phases were followed by a phase of Tertiary volcanism and a subsequent period of uplift. Potential source rocks include oil-prone, Upper Carboniferous lacustrine shales, oil-prone Upper Permian marine shales, and gas-prone Upper Jurassic marine shales. The shales are generally immature in outcrop with the exception of areas surrounding larger Tertiary intrusions and areas with a high density of Tertiary sills. In these areas sediments are postmature. The potential source rocks are believed to be adequately buried with respect to oil-generation only in the easternmost part of the area, where they apparently passed into the oil-window during Cretaceous time. In this area four play concepts have been suggested, all with Upper Palaeozoic source rocks and respectively Upper Carboniferous, Upper Permian, Middle Jurassic and Upper Jurassic–Lower Cretaceous reservoirs.