Preboreal onset of cold-water coral growth beyond the Arctic Circle revealed by coupled radiocarbon and U-series dating and neodymium isotopes.

López Correa, M., Montagna, P., Joseph, N., Rüggeberg, Andres, Fietzke, Jan , Flögel, Sascha, Dorschel, B., Goldstein, S. L., Wheeler, A. and Freiwald, Andre (2012) Preboreal onset of cold-water coral growth beyond the Arctic Circle revealed by coupled radiocarbon and U-series dating and neodymium isotopes. Quaternary Science Reviews, 34 . pp. 24-43. DOI 10.1016/j.quascirev.2011.12.005.

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Cold-water coral mounds of Lophelia pertusa are widespread across the Scandinavian shelf, which was completely ice-covered during the Last Glacial Maximum between 22 to 18 ka BP. Rapid deglacial meltdown of the Fennoscandian inland ice and the retreat of its ice-streams freed most of the shelf of ice by ∼15 ka BP. However, cold-water coral growth commenced only after the Pleistocene–Holocene transition at 11.65 ka BP, when modern-like climatic patterns and oceanographic conditions were established. A tight climatic coupling has been constrained with U-series ages. Coupled 14C ages provide local reservoir ages from various gravity cores in a fjord-setting in Stjernsund at 70°N and on the open shelf in Trænadjupet at 66°N. Reinvestigation of earlier 14C coral chronologies suggests that coral ecosystems widely established themselves across the entire 3000 km long Scandinavian shelf prior to ∼10 ka BP. The earliest occurrence of Madrepora oculata at ∼2.4 ka BP suggests a late Holocene colonization of the Norwegian shelf, which is linked to a prominent mound growth hiatus in Trænadjupet (64°N). Mound growth rates near the northern biogeographic boundary of L. pertusa with up to ∼614 cm ka−1 during certain growth periods are much higher than the previously reported fastest rates of ∼220 cm ka−1 from the Irish margin. Contemporaneous rapid fjordbasin sedimentation is slower with ∼63 cm ka−1. Matrix 14C ages overlap with coral 14C ages from the same horizon. This indicates rapid framework construction and efficient trapping of background sediment. Hiatuses are frequent in on-mound sediments and only short periods of coral growth are recorded. Coupled Δ14C and εNd values indicate a persistent Holocene inflow of the North Atlantic Current in Stjernsund, but also deglacial meltwater mixing during the early Holocene prior to ∼9.5 ka BP. Reservoir ages are overall close to the surface marine reservoir age, but ΔR is highly localized.

Document Type: Article
Keywords: Meeresgeologie; Paleoceanography; Climatology; Cold-water corals; Reservoir ages; Biogeography; Rapid climate change; Younger Dryas; Deglacial; Water mass mixing; Poseidon; POS325
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.quascirev.2011.12.005
ISSN: 0277-3791
Related URLs:
Projects: HERMES, Future Ocean
Date Deposited: 24 Feb 2012 11:36
Last Modified: 16 Sep 2016 08:10

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