Glaciations

Fennoscandia has experienced major uplift in post-glacial time. The rate of uplift along the coasts is so high that its effects have been observed within one generation. In the northern Gulf of Bothnia uplift is occurring at 9 mm/yr. Similar uplift is observed also on Svalbard. This uplift is basically due to the melting of the glacier that started 20 000 years ago (cf. Figure below). We have a lot of data from the last glaciation, which gives us the possibility of investigating how the glacier affected the areas.

There has been numerous glaciations in the area over the last 3 million years. The glaciers has significantly affected the Barents Sea because of its ability to erode. Quantitative estimates show that there has been a huge redistribution of sediment mass in Scandinavia and the Barents Sea over the last few million years due to the glaciations.

Deglaciation in Fennoscandia

Extensive petroleum exploration has taken place in the Barents Sea from the 1970's, but the exploration has not been that successful on the Norwegian sector. In contrast, the exploration in the Russian sector has resulted in discoveries of several giant gas fields (e.g. Shtockman). Large oil fields have been found in the Pechora Sea in the SE part of the Barents Sea.

 

Calculated present rate of uplift in the Barents Sea

The reason for the different exploration success rates in the western and eastern Barents Sea is not well understood. The conditions for developing petroleum systems are present in the entire Barents Sea, with numerous levels of source rocks and potential traps. The problems of finding commercial hydrocarbon deposits in the Norwegian Barents Sea have been attributed to glacial erosion and uplift causing seal failure and expulsion of hydrocarbons from previously filled traps.

 

Mapped Plio-Pleistocene erosion of Northern Europa

 

The uplift also have caused a cooling of potential source rocks, turning off the hydrocarbon generation. There are major geological differences between the western and eastern Barents Sea. The western Barents Sea is characterized by broad platform areas cut by fairly narrow rifts. In contrast, the Eastern Barents Sea is a very broad and deep sag basin with little internal structuring. Currently, the nature and origin of these differences are not well documented and understood.