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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Abstract

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
Expeditions/Models/Experiments:
Date Deposited: 24 Feb 2012 11:36
Last Modified: 16 Sep 2016 08:10
URI: http://oceanrep.geomar.de/id/eprint/13792

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