Open Session - SWISS GEOSCIENCE MEETINGs

166
Symposium 5: Quaternary Research
Figure 2. Cartoon of carbon fluxes into a lake sediment. Resilient organic matter builds up in soils. In the past, as well as at present, a
small fraction of the soil erodes, and the sediment receives thus each year a 'snapshot' of the soil carbon pool, that can be dated using 14 C.
REFERENCES
Smittenberg, R.H., T.I. Eglinton, S. Schouten, J.S. Sinninghe Damsté, 2006, Ongoing build-up of refractory organic carbon in
boreal soils during the Holocene. Science 314, 1283
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Record of past environmental and climatic changes in the sediments of
Lake Pfafforet (Valais, Switzerland)
Straub Marietta*, Wick Lucia**, Anselmetti Flavio***, Gilli Adrian*, Guélat Michel****, Mottet Manuel*****, Paccolat
Olivier******, Rentzel Philippe**
* Department of Earth Science, Swiss Federal Institute of Technology (ETH) Zürich
** Institute for Prehistory and Archaeological Science, IPAS, University Basel, Spalenring 145, 4055 Basel
*** Eawag, Swiss Federal Institute of Aquatic Science & Technology
****Géologue, Creux de la Terre 11, 2800 Delémont
***** Bureau ARIA, Rue de Loèche 11, 1950Sion
****** Bureau TERA, Rue du Pré-Fleuri 12, 1950 Sion
A 5 m long sediment record of Lake Pfafforet (Valais, Switzerland) indicates significant changes in paleo-climate, paleo-vegetation
and paleo-hydrology over the last ≈4000 yrs BP in the Pfyn-Forest. These changes are correlated to nearby situated archaeological
sites, which show a long history of human occupation in the area.
Lake Pfafforet is situated within the Pfyn-Forest in the Rhone valley between Leuk and Sierre. The Pfyn-Forest is characterised
by a special micro-climate, with very hot summers and cold winters that are more extreme than average. The undulating
and irregular morphology of the area is built up by slide deposits from the rockslide of Sierre, which is estimated to be
≈15’000 years old (Burri 1997), although no precise dating exists today. Within the Pfyn-Area, archaeological excavations on
relicts from the Iron Age, the Roman Period and Mediaeval Period were carried out, which triggered interest in the climatic
and the environmental situation during these historic times. As Lake Pfafforet is the deepest natural lake in the Pfyn-Forest
(Bendel et al., 2006), its sediment record was targeted to get information about the past climatic and environmental evolution.