Université de Fribourg

Early diagenetic imprint on temperature proxies in holocene corals: a case study from french polynesia

Rashid, Rashid ; Eisenhauer, Anton ; Liebetrau, Volker ; Fietzke, Jan ; Böhm, Florian ; Wall, Marlene ; Krause, Stefan ; Rüggeberg, Andres ; Dullo, Wolf-Christian ; Jurikova, Hana ; Samankassou, Elias ; Lazar, Boaz

In: Frontiers in Earth Science, 2020, vol. 8, p. -

Coral-based reconstructions of sea surface temperatures (SSTs) using Sr/Ca, U/Ca and δ18O ratios are important tools for quantitative analysis of past climate variabilities. However, post-depositional alteration of coral aragonite, particularly early diagenesis, restrict the accuracy of calibrated proxies even on young corals. Considering the diagenetic effects, we present new Mid to Late...

Université de Fribourg

Boron isotope composition of the cold-water coral Lophelia pertusa along the Norwegian margin: Zooming into a potential pH-proxy by combining bulk and high-resolution approaches

Jurikova, Hana ; Liebetrau, Volker ; Raddatz, Jacek ; Fietzke, Jan ; Trotter, Julie ; Rocholl, Alexander ; Krause, Stefan ; Mc Culloch, Malcolm ; Rüggeber, Andres ; Eisenhauer, Anton

In: Chemical Geology, 2019, vol. 513, p. 143–152

High-latitude cold-water coral reefs are particularly vulnerable to climate change due to enhanced CO2 uptake in these regions. To evaluate their physiological functioning and potential application as pH archives, we retrieved both recent and fossil samples of Lophelia pertusa along the Norwegian margin from Oslofjord (59°N), over to Trondheimsfjord, Sula and Lopphavet (70.6°N). Boron...

Université de Fribourg

Environmental constraints on Holocene cold‐water coral reef growth off Norway: Insights from a multiproxy approach

Raddatz, Jacek ; Liebetrau, Volker ; Trotter, Julie ; Rüggeberg, Andres ; Flögel, Sascha ; Dullo, Wolf-Christian ; Eisenhauer, Anton ; Voigt, Silke ; McCulloch, Malcolm

In: Paleoceanography, 2016, vol. 31, no. 10, p. 1350–1367

High-latitude cold-water coral (CWC) reefs are particularly susceptible due to enhanced CO₂ uptake in these regions. Using precisely dated (U/Th) CWCs (Lophelia pertusa) retrieved during research cruise POS 391 (Lopphavet 70.6°N, Oslofjord 59°N) we applied boron isotopes (δ¹¹B), Ba/Ca, Li/Mg, and U/Ca ratios to reconstruct the environmental boundary conditions of CWC reef growth. The...

Université de Fribourg

Environmental boundary conditions of cold-water coral mound growth over the last 3 million years in the Porcupine Seabight, Northeast Atlantic

Raddatz, Jacek ; Rüggeberg, Andres ; Liebetrau, Volker ; Foubert, Anneleen ; Hathorne, Ed C. ; Fietzke, Jan ; Eisenhauer, Anton ; Dullo, Wolf-Christian

In: Deep Sea Research Part II: Topical Studies in Oceanography, 2014, vol. 99, p. 227–236

IODP Expedition 307 made it for the first time possible to investigate the entire body of a cold-water coral carbonate mound. Here we provide new insights into the long-term history of Challenger Mound on the European continental margin off Ireland. This study is based on age determinations (230Th/U, 87Sr/86Sr) and geochemical signals (Mg/Li and Ba/Ca) measured in the scleractinian cold-water...

Université de Fribourg

Stable isotope profiles (Ca, O, C) through modern brachiopod shells of T. septentrionalis and G. vitreus: Implications for calcium isotope paleo-ocean chemistry

Allmen, Katja von ; Nägler, Thomas F. ; Pettke, Thomas ; Hippler, Dorothee ; Griesshaber, Erika ; Logan, Alan ; Eisenhauer, Anton ; Samankassou, Elias

In: Chemical Geology, 2010, vol. 269, no. 3-4, p. 210-219

Brachiopod shells are widely used as an archive to reconstruct elemental and isotopic composition of seawater. Studies, focused on oxygen and carbon isotopes over the last decades, are increasingly extending to the emerging calcium isotope system. To date, only little attention has been paid to test the reliability of fossil brachiopods on their modern counterparts.In this context, the present...