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Fossile shells

11 August 2010 16:03

Simon Troelstra and his wife Syta come searching for fossile shells. In this video he explains why he finds these molluscs above sea level.
Ten thousand years ago, the glacier disappeared at this location. The bare bed rock was quickly covered with silt and a rich layer of molluscs established. Later, this was covered with more cobbles and silt, but the beach also moved higher now the weight of the glacier had disappeared. Nowadays there are terraces upto ten metres above sea level, where fossile shells can be found.

At home Simon studies the annual growth lines in the shells and takes minute samples to look at isotopic composition. Together with the foraminifera in the soil, this will tell him about the holocene environment.

The first sites are close to town. The fjord front is a raised beach and we find many shell fragments. While burrying the sewage pipes, many shells were moved to the surface.

The second site is near the marine laboratory. Twenty years ago this coastline was moved inwards to gain stones for the harbour quay. Now it is a nice profile with shells in the proper layer.
In front of the station Attacked on the tundra
Near Gasebu the shells are found in another situation. Here the shells are brought to the surface by permafrost action.

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