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| Maccali, Jenny; Hillaire-marcel, Claude; Ghaleb, Bassam; Ménabréaz, Lucie; Blénet, Aurélien; Edinger, Evan; Hélie, Jean-françois; Preda, Michel. |
| About 70 fossil and live-collected specimens of Desmophyllum dianthus were collected from steep rocky surfaces and time-averaged assemblages at their base (“coral graveyards”) in the southern Labrador Sea at depths ranging from ~1700 m (Orphan Knoll) to ~2200 m (Flemish Cap). Aside from stable isotope and mineralogical analysis, U-series and 14C age determinations were performed on the samples. Fossil corals from the coral graveyards display two principal age clusters corresponding respectively to the Holocene and Marine Isotope Stage (MIS) 5c intervals. Three samples lay outside these clusters, at ~13.5 ka (Bølling-Allerød), ~ 64 ka (MIS 3) and at ~181 ka (MIS 7a). The clusters are thought to record intervals with both i) high food availability, either... |
| Tipo: Text |
Palavras-chave: Deep-sea corals; Aragonite corals; Labrador Sea; Radiocarbon; U-series dating. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00623/73496/72790.pdf |
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| Wefing, Anne-marie; Arps, Jennifer; Blaser, Patrick; Wienberg, Claudia; Hebbeln, Dierk; Frank, Norbert. |
| High-precision U-series dating of scleractinian cold-water corals is a key chronological tool for studies of past environmental and climate conditions. Here, we tested and optimized an automated chemical extraction system (ESI prepFAST-MC equipped with an Eichrom TRU-resin chromatographic column) for its ability to purify U and Th isotopes for mass spectrometric U-series dating at the sub-‰ precision level. Chemical yields are constantly high, on average around 90% for both U and Th. Analytical blanks are comparable to manual purification (< 0.15 pg U, 0.15 pg Th for a typical sample of 50 mg) and memory effects due to the recycling of the column are mostly insignificant as the carry-over fraction is about 10− 5 for Th and 10− 3 for U isotopes. However,... |
| Tipo: Text |
Palavras-chave: U-series dating; PrepFAST-MC; Cold-water corals; South Atlantic; Angola; Past climate. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00409/52058/52761.pdf |
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| Frank, Norbert; Ricard, Estelle; Lutringer-paquet, Audrey; Van Der Land, Cees; Colin, Christophe; Blamart, Dominique; Foubert, Anneleen; Van Rooij, David; Henriet, Jean-pierre; De Haas, Henk; Van Weering, Tjeerd. |
| U-series dating of constructional cold-water corals is a powerful tool to reconstruct the evolution of corals on carbonate mounds. Here we have investigated the time framework of corals such as Lophelia pertusa and Madrepora oculata on five different mound settings of the eastern North Atlantic (on Rockall Bank and in Porcupine Seabight), sampled at variable depth and location (610-880 m water depth). We have found that the past 11 ka reflect a period generally favourable for coral development. We further determined local mound growth rates and identified mound surface erosion (framework collapse) during times of active coral framework construction. "Local" vertical mound growth rates vary between less than 5 cm ka(-1) and up to 220 cm ka(-1). We interpret... |
| Tipo: Text |
Palavras-chave: Carbonate mound; Deep sea corals; U-series dating; Climate; Rockall Bank; Porcupine Seabight. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00219/33060/31574.pdf |
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