Masterprosjekt vår 2019 ved GEO - Nele Meckler
Eemian warmth in Bergen - revisiting the classic Fjøsanger site with a novel tool
The classical Fjøsanger site in Bergen is a unique location, as it encompasses the full Eemian interglacial, which is thought to have been warmer than today and thus could serve as an analogue for warming in the near future. The site also includes sediments showing climate fluctuations during the Early Weichselian. Fjøsanger is the northernmost Eem location on the European coastline and is thus a crucial location for understanding the geographic distribution of Eemian warmth, as well as the extent of ice melt in Scandinavia and on Greenland. Previously, semi-quantitative temperature reconstructions have been based on fossil (mollusk, foraminifera and pollen) assemblages, relying on the assumed temperature dependence of species distributions.
Clumped isotope thermometry is a novel technique for reconstructing carbonate formation temperatures based on the ordering ("clumping") of stable isotopes within molecules. Being based on thermodynamics, this very different temperature proxy promises quantitative temperature reconstructions independent of other factors.
Hypothesis (scientific problem)
The Eemian interglacial was globally warmer than the present and sea level was significantly higher, potentially reflecting ice loss from Greenland. Revisiting the Fjøsanger section with our novel tool will allow reliable reconstruction of temperatures at the Norwegian coast and thus assessing the likelihood of significant ice melt on Greenland and in Scandinavia.
We have mollusc samples from the classic Fjøsanger site, covering the full glacial-interglacial-glacial cycle, including the Eemian Interglacial. The master student will obtain carbonate samples from the shells using a drilling device, prepare them for analysis, conduct the clumped isotope measurements on a mass spectrometer, and convert the data into temperature values. The new time series of temperature change will be compared with previous interpretations of fossil and pollen assemblages.
Krav for opptak
Felt-, lab- og analyse- arbeid
Ingen feltarbeid, labarbeid ca. 6 måneder