Carboniferous Lacustrine Shale in East Greenland— Additional Source Rock in Northern North Atlantic?
Lars Stemmerik, Flemming G. Christiansen, Stefan Piasecki, 1990. "Carboniferous Lacustrine Shale in East Greenland— Additional Source Rock in Northern North Atlantic?", Lacustrine Basin Exploration: Case Studies and Modern Analogs, Barry J. Katz
Download citation file:
Lacustrine organic-rich shales have been recorded at three stratigraphie levels within the uppermost Devonian-Lower Permian continental sequence of central east Greenland. The Westphalian lacustrine shales, considered here, are divided into an epilimnic association of silty shale and sandstone dominated by terrestrial organic material, and a hypolimnic association of clay shale dominated by amorphous kerogen and algae. The hypolimnic shales display hydrogen index values between 300 and 900 mg HC/g TOC and TOC between 2 and 10%, and can be characterized as potential oil-prone source rocks.
The lacustrine basins are expected to be 10-15 km wide and tens of kilometers along strike with net source rock thickness in excess of 50 m and generative potential in excess of 3 million m3/km2. The shales form a hitherto overlooked potential source rock in the east Greenland basin with implications for areas offshore Norway.
Figures & Tables
Lacustrine Basin Exploration: Case Studies and Modern Analogs
Lacustrine environments are a major contributor of petroleum source rocks. Lacustrine source rock prediction is, however, influenced by numerous, complex variables governing lake sedimentation. Current predictive capability can be improved by attempting to map essential climatic variables to limit in space and time the area of lacustrine source rock exploration. Climatic characteristics that govern lake occurrence and the potential for stratification have been investigated with a General Circulation Model of the atmosphere for the present and for the mid-Cretaceous. In this analysis, the distribution of areas with a positive water balance first is used as an indicator of the distribution of areas conducive to lake formation. Second, the distribution of areas that experience large annual climatic variations is used as an indicator of the distribution of lakes that are less likely to be stratified and, hence, less likely to be sites of high organic-carbon preservation. Four factors used to define large climatic variations include (1) seasonal temperature cycle in excess of 40°C; (2) seasonal temperature extreme of less than 4C°; (3) average seasonal differences in precipitation minus evaporation balance in excess of 5 mm/ day; and (4) distribution of mid-latitude winter storms. Evidence is presented to support the capability of climate models that add insight into lacustrine source rock prediction by simulating geographic regions conducive to lake development and to stratification and organic-carbon preservation