|Title||The Upper Laacher See Tephra in Lake Geneva sediments: paleoenvironmental and paleoclimatological implications|
|Publication Type||Journal Article|
|Year of Publication||1997|
|Authors||Moscariello A, Costa F|
|Journal||Schweizerische Mineralogische Und Petrographische Mitteilungen|
Microstratigraphical analysis of Late glacial lacustrine sediments from Geneva Bay provided evidence of a tephra layer within the upper Allerod biozone. The layer consists of alkali feldspar, quartz, plagioclase, amphibole, pyrex ene, opaques, titanite and glass shards. Electron microprobe analyses and morphological study of glass shards allowed correlation with the upper part of the Laacher See Tephra of the Laacher See volcano (Eifel Mountains, Germany). Sedimentological features of enclosing lacustrine sediments suggest that a momentary decrease in precipitation occurred in the catchment area and consequent reduction in detrital supply in the lake, after the ash fall-out. This has been interpreted as the environmental response to a momentary cooling following the Laacher See Tephra aerosols emission. Comparison with sedimentological features characterizing the Allerod-Younger Dryas transition highlights the sensitivity of Lake Geneva system in recording both short and long-terms climate-induced environmental changes.