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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

Origin and age of carbonate clasts from the Lusi eruption, Java, Indonesia

Samankassou, Elias ; Mazzini, Adriano ; Chiaradia, Massimo ; Spezzaferri, Silvia ; Moscariello, Andrea ; Couto, Damien Do

In: Marine and Petroleum Geology, 2018, vol. 90, p. 138–148

Deep stratigraphic constrains below the Indonesian Lusi mud eruption are currently lacking due to the absence of deep wells and good quality seismic data. A collection of carbonate clasts has been sampled from the Lusi site, active since its birth in 2006. These specimens are part of a large variety of lithotypes erupted from the main crater. The carbonates analysed comprise scleractinian...

Université de Fribourg

Barium isotope fractionation during experimental formation of the double carbonate BaMn[CO₃]₂ at ambient temperature

Böttcher, Michael E. ; Geprägs, Patrizia ; Neubert, Nadja ; Allmen, Katja von ; Pretet, Chloé ; Samankassou, Elias ; Nägler, Thomas F.

In: Isotopes in Environmental and Health Studies, 2012, p. -

In this study, we present the first experimental results for stable barium (Ba) isotope (¹³⁷Ba/¹³⁴Ba) fractionation during low-temperature formation of the anhydrous double carbonate BaMn[CO₃]₂. This investigation is part of an ongoing work on Ba fractionation in the natural barium cycle. Precipitation at a temperature of 21±1°C leads to an enrichment of the lighter Ba isotope...

Université de Fribourg

Carbonate mounds in shallow and deep time

Henriet, J.-P. ; Spezzaferri, Silvia ; Samankassou, Elias ; Foubert, A. ; Rooij, D. Van ; Rüggeberg, A.

In: Marine Geology, 2011, vol. 282, no. 1-2, p. 1-4

Special Issue on COld-water CArbonate Reservoir systems in Deep Environments - COCARDEOver a decade of research on recent cold-water coral mounds in various oceans has set the stage for comparative studies between recent and ancient carbonate mound systems, with the aim to unravel generic processes and reveal the “red thread” in a fundamental strategy of Life building Geology — a strategy...

Université de Fribourg

Barium isotope fractionation in the global barium cycle: First evidence from barium minerals and precipitation experiments

Allmen, Katja von ; Böttcher, Michael E. ; Samankassou, Elias ; Nägler, Thomas F.

In: Chemical Geology, 2010, vol. 277, no. 1-2, p. 70-77

In this study, we present first results from an ongoing investigation on the stable barium (Ba) isotope fractionation in the natural barium cycle. Stable Ba isotope signatures of international IAEA reference materials (synthetic barium sulfate, IAEA-SO-5, -6, and barium carbonate, IAEA-CO-9), natural Ba minerals and experimental Ba precipitates have been analyzed as a first approach to evaluate...

Université de Fribourg

Microfacies and depositional setting of the Upper Triassic mid-oceanic atoll-type carbonates of the Sambosan Accretionary Complex (southern Kyushu, Japan)

Chablais, Jérôme ; Martini, Rossana ; Samankassou, Elias ; Onoue, Tetsuji ; Sano, Hiroyoshi

In: Facies, 2010, vol. 56, no. 2, p. 249-278

The Upper Triassic shallow-water limestones of the Sambosan Accretionary Complex are reconstructed as a remnant of a mid-oceanic atoll-type build-up upon a seamount in the Panthalassan Ocean. The Sambosan atoll-type carbonates and its pedestal were accreted along with deep-water ribbon-chert and related siliceous rocks to the eastern margin of Asia during the Late Jurassic to Early Cretaceous....