ABSTRACT

Dr. Villy Fjeldskar - Chief Scientist, Tectonor, Stavanger, Norge

During the Quaternary (last 2.8 million years), northern Europe has probably experienced more than 30 glaciations. The glaciations have significantly influenced the temperature history of sedimentary basins, and associated hydrocarbon maturation in potential source rock. Repeated episodes of growth and withdrawal of huge glaciers, glacial erosion and associated sediment deposition also lead to geologically dramatic changes in surface loading. The lithosphere responds to these changes by subsiding under loading, and by uplifting when loading is removed. Differential vertical movement of the lithosphere related to glacial isostasy lead to repeated tilting of sedimentary formations and potential petroleum reservoirs therein, which may greatly affect hydrocarbon migration directions in former glaciated areas.

The effect of glaciations has recently gained significant interest from the petroleum industry, not least due to the effect glaciations may have contributed to the huge accumulation in the "Johan Sverdrup" field recently discovered in the Norwegian North Sea.