Exploring short-term ecosystem dynamics in connection with the Early Holocene Saksunarvatn Ash fallout over continental Europe. (1st February 2021)

• Record Type: Journal Article
• Authors: Zanon, Marco; Feeser, Ingo; Dreibrodt, Stefan; Schwark, Lorenz; van den Bogaard, Christel; Dörfler, Walter
• Is Part Of: Quaternary science reviews. Volume 253(2021)
• Publication Date: 2021-02-01
• Subjects: Saksunarvatn tephra -- Tephrochronology -- Tephrostratigraphy -- 10.3 ka event -- Early Holocene -- Annually laminated sediments -- Environmental dynamics -- Germany; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2020.106772
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: Estimating the environmental and societal impact of recent volcanic eruptions is a task aided by direct measurements and historical sources. Beyond the reach of first-hand accounts, our understanding of pre-historic volcanism is often hindered by dating uncertainties inherent to geological archives. Here, we minimize dating errors by analyzing the annually laminated sequences of two Central European lakes, Poggensee and Woseriner See. We focus on environmental transformations that occurred in the decades preceding and following the deposition of the Icelandic Saksunarvatn tephra, dated between ca. 10, 300 and 10, 200 cal. BP. As a first result, we provide two new independent age determinations for the ash layer detected in both sequences. Our estimates (10, 264 ± 24 cal. BP at Poggensee and 10, 282 ± 45 cal. BP at Woseriner See) place the age of this tephra deposit closer to Greenland estimates than to continental ones, possibly reducing the chronological gap between the multiple fallout events that characterize the Saksunarvatn Ash. A high resolution palaeoenvironmental characterization was carried out via pollen, thin sections and geochemical analysis. Both sequences show traces of a contemporaneous disturbance event dated to ca. 18 years before tephra deposition. In addition, environmental impact compatible with a cooling event is discernible for ca. 15 years following tephra deposition. While independent climate mechanisms can be responsible for the observed trends, we explicitly focus on exploring volcanic eruptions as a possible leading driver. A consistent agreement across all proxies is lacking in the pre-tephra record, yet sulfur enrichment and acidification processes allow us to suggest volcanism as a plausible trigger. Combined with the post-tephra cooling, the two sedimentary records depict a possible scenario of multi-decadal, continuous volcanic impact. Highlights: A single Saksunarvatn Ash layer was detected in two varved lake cores from N-Germany. The ash layers in the two cores are dated to 10, 282 ± 45 and 10, 264 ± 24 cal. BP. Palynological and geochemical analysis were conducted in proximity of the ash layers. Environmental disturbance, possibly linked to volcanism, predates the ash fallout. Evidence for a ca. 15-year-long cooling is recognizable after tephra deposition.