Stora Vidarvatn and Litla Vidarvatn:

These lakes ("Big" and "Little" Vidarvatn) were selected for a study of Holocene climate because of their hypothetically sensitive location in the northeastern corner of Iceland. Results so far are presented in Axford et al. 2007 (QSR) and 2008 (JOPL).

Location:

Iceland's location in the North Atlantic (left); and the location of the study site (indicated by the red dot) in Iceland (right).

Topographic Setting:

Stora Vidarvatn and Litla Vidarvatn represent two very different lake environments (e.g., Stora Vidarvatn is almost 50 m deep, whereas Litla Vidarvatn is less than 3 m deep). On the other hand, because these lakes are located at similar elevations and within 1 km of each other, they experience the same regional climatic conditions. By studying parallel cores from both lakes, we hope to be able to distinguish edaphic changes and lake ontogeny (i.e. lake-specific processes) from regional climatic changes recorded in the sediments.

Below are two photos of Stora Vidarvatn, one showing the area around the lake's outlet (truck for scale), and one showing the main lake basin (our boat is a tiny white dot in the distance).

Lake Bathymetry:

Depths are shown in meters. (Axford, unpublished data. Maps are NOT drawn to the same scale.)

The Cores:

We have recovered continuous piston cores from both Stora and Litla Vidarvatn (8.0 and 6.2 m long, respectively) that extend back to before the deposition of the Saksunarvatn tephra (~10,200 cal yr B.P.). These cores, which contain datable macrofossils, numerous tephra layers, and abundant chironomid head capsules, are being used to reconstruct the Holocene environmental history of northeast Iceland. We also have surface cores (which capture the sediment-water interface intact) that extend back about 1000 years. They have been sampled at high resolution, and (along with the uppermost sediments from the piston cores) used to take a close look at environmental changes of the last two millenia.

Photo: Hillary Rosner and Elizabeth McNie sample a surface core from Stora Vidarvatn, July 2005.
Surface cores like this one capture the uppermost sediments without disturbing them, and thus extend the paleoclimate record up to present-day. Future work will take a close look at climate changes of the last 2000 years at this lake, placing any recent changes in the context of the last two millenia.