Radiocarbon Dating of Small-sized Foraminifer Samples: Insights into Marine sediment Mixing
Year: 2020
Type: article
Abstract: ABSTRACT Radiocarbon (14C) can be used to build absolute chronologies and reconstruct ocean ventilation over the last 40 ka. Sample size requirements have restricted14C measurements in marine cores with low foraminifer content, impeding14C-based studies focused on abrupt climate events. Recent developments have demonstrated that small-sized foraminifer samples can now be dated using a gas introduction system at the cost of a small decrease in precision. We explore the potential of gas measurements on benthic and planktonic foraminifers from core SU90-08 (43°03′1″N, 30°02′5″W, 3080 m). Gas measurements are accurate, reproducible within 2σ uncertainty and comparable to graphite measurements. Both techniques yield negative14C benthic-planktonic (B-P) age-offsets after Heinrich event 1. We argue that negative B-P ages result from bioturbation and changes in foraminifer abundances, with the chance of negative B-P especially increased when the14C age gradient between the deep and surface waters is decreased. Small-sized14C measurements seem to capture the variance of the foraminifera age distribution, revealing the active mixing in those archives. Sediment deposition and mixing effects possibly pose a greater obstacle for past14C-based dating and ocean ventilation reconstructions than the measurement precision itself, particularly in relatively low sedimentation rate settings.
Source: Radiocarbon
DOI: 10.1017/rdc.2020.13
Institutions: Centre National de la Recherche Scientifique, Université de Versailles Saint-Quentin-en-Yvelines, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, UNSW Sydney, Laboratoire des Sciences du Climat et de l'Environnement, Climate Change Research Centre, ETH Zurich, Uppsala University, University of Cambridge, Université Paris-Sud, Geosciences Paris-Saclay, Lyon 1 Université, École Normale Supérieure de Lyon, Université de Lyon, Max Planck Institute for Chemistry, Laboratoire de Géologie de Lyon : Terre, Planètes et Environnement, Université Jean Monnet, CEA Paris-Saclay - Etablissement de Saclay, CEA Paris-Saclay
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,575
Awards: G2109279595, G3207356259, G393177772, Moving beyond the age-depth paradigm in palaeoceanography, G5324585312, New insights into abrupt climate change using isotope model-data fusion, G5702163051, Resolving the ocean's role in deglacial radiocarbon cycling (OCEAN-14), Elucidating the Causes and Effects of Atlantic Circulation Changes through Model-Data Integration, G712881263, G7828494648
OpenAlex ID: W3011503844