Lac du Bourget

Country:

France

Region:

Savoie

Lake type:

glacial lake

Category: mixed varves

Elevation:

231 m asl

Max depth:

145 m

Surface area:

44.5 km2

Archive type:

lacustrine sediments

Author of images:

Dirk Enters

Reference:

Giguet-Covex C., Arnaud F., Poulenard J., Enters D., Reyss J.-L., Millet L., Lazzaroto J. and Vidal O. 2010. Sedimentological and geochemical records of past trophic state and hypolimnetic anoxia in large, hard-water Lake Bourget, French Alps. Journal of Paleolimnology 43: 171-190

Link to reference or DOI:

http://dx.doi.org/10.1007/s10933-009-9324-9

Flatbedscan with polarized light of calcite varves from Lac du Bourget, composed of a diatom layer (spring lamina), a bio-precipitated calcite-rich layer (spring/summer lamina), and a layer rich in organic matter and detrital particles (winter lamina). Some other features are visible in this image: An oxidation front runs vertical approximately in the center of the image. The slightly lighter colored sediment on the left side is oxidized upon contact with air, while the sediment on the right is still reduced (the sediment slab was taken perpendicular to the split core surface). To the very right of the slab the sediment has been disturbed during coring (contact with PVC liner). > max. resolution