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

  • Raddatz, Jacek GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
  • Rüggeberg, Andres GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany - Renard Centre of Marine Geology, Department of Geology and Soil Sciences, Ghent University, Belgium - Department of Geosciences, University of Fribourg, Switzerland
  • Liebetrau, Volker GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
  • Foubert, Anneleen GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany - Department of Geosciences, University of Fribourg, Switzerland - Department of Earth and Environmental Sciences, KU Leuven, Belgium
  • Hathorne, Ed C. GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
  • Fietzke, Jan GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
  • Eisenhauer, Anton GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
  • Dullo, Wolf-Christian GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
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    24.06.2013
Published in:
  • Deep Sea Research Part II: Topical Studies in Oceanography. - 2014, vol. 99, p. 227–236
Cold water corals
Challenger Mound
IODP Site 1317
Lophelia pertusa
Mg Li
Ba Ca
Mediterranean Outflow Water
English 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 coral Lophelia pertusa from IODP Site 1317 in the Porcupine Seabight. The paleoceanographic reconstructions reveal that coral growth in the Porcupine Seabight was restricted to specific oceanographic conditions such as enhanced export of primary production and Bottom-Water Temperatures (BWT) between ∼8 and 10 °C, related to the water mass stratification of the Mediterranean Outflow Water (MOW) and Eastern North Atlantic Water (ENAW). The geochemical signals from the coral skeletons can be explained by the close interaction between cold-water coral growth, sea-surface productivity and the surrounding water masses – the boundary layer between MOW and ENAW. Enhanced sea-surface productivity and the build-up of a stable water mass stratification between ENAW and MOW caused enhanced nutrient supply at intermediate water depths and facilitated a steady mound growth between ∼3.0 and 2.1 Ma. With the decrease in sea-surface productivity and related reduced export productivity the food supply was insufficient for rapid coral mound growth between ∼1.7 and 1 Ma. During the late Pleistocene (over the last ∼0.5 Myr) mound growth was restricted to interglacial periods. During glacials the water mass boundary between ENAW/MOW probably was below the mound summit and hence food supply was not sufficient for corals to grow.
Faculty
Faculté des sciences et de médecine
Department
Département de Géosciences
Language
  • English
Classification
Geology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/303640
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