Vegetation, insects, molluscs and stable isotopes from Late-Würm deposits at Lobsigensee (Swiss Plateau)
Abstract
At a littoral site of Lobsigensee northwest of Bern pollen (including Betula, pollen size measurements), plant macrofossils, Coleoptera, Trichoptera, Chironomidae, Ceratopogonidae, Mollusca, delta-18C and delta-13C from Late-Würm sediments were studied. In the clay of Oldest Dryas the expansion of Betula nana was recorded from the level where the first Coleoptera, Trichoptera and Mollusca occurred and a change in the chironomid fauna took place. The transition from Oldest Dryas to Bölling was sharply marked by the sediment (clay/lake marl transition), by vegetation (beginning of reforestation), by chironomid fauna (disappearance of cold stenothermic species) and by high mollusc frequencies; only a small rise of delta-18C in carbonate is recorded. During the Bölling a faunal shift among Coleoptera and Trichoptera suggests a rise of mean July temperature from 10-12°C to 14-16°C. No climatic cooling between Bölling and Alleröd was found. A Younger Dryas climatic cooling was indicated by pollen diagrams, by delta-18C and by a minimum among molluscs, but not by changes in the species composition of the insects. These data support the view that rising annual and summer temperatures favored a vegetational and faunal development reaching a major step around 13 300-13 000 B.P.; the only climatic reversal registered was the Younger Dryas.
Date Issued
1983
Publication Type
Article
Subject(s)
Language(s)
en
Author(s)
Chaix, Louis | |
Eicher, Ulrich | |
Elias, Scott A. | |
Gaillard, Marie-José | |
Hofmann, Wolfgang | |
Siegenthaler, Ulrich | |
Toboiski, Kazimierz | |
Wilkinson, B. |
Additional Credits
Journal
Revue de Paléobiologie
Publisher
Muséum d'Histoire naturelle de Genève
ISSN
0253-6730
Access(Rights)
restricted