The Upper Laacher See Tephra in Lake Geneva sediments: paleoenvironmental and paleoclimatological implications

TitleThe Upper Laacher See Tephra in Lake Geneva sediments: paleoenvironmental and paleoclimatological implications
Publication TypeJournal Article
Year of Publication1997
AuthorsMoscariello A, Costa F
JournalSchweizerische Mineralogische Und Petrographische Mitteilungen
Volume77
Pagination175-185
ISBN Number0036-7699
Accession NumberWOS:A1997XR43700005
Abstract

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.