Sr-87/Sr-86 as a quantitative geochemical proxy for C-14 reservoir age in dynamic, brackish waters: Assessing applicability and quantifying uncertainties
2016 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 2, 735-742 p.Article in journal (Refereed) PublishedText
Accurate geochronologies are crucial for reconstructing the sensitivity of brackish and estuarine environments to dynamic external impacts of the past. Radiocarbon (C-14) dating is commonly used for palaeoclimate studies, but its application in brackish environments is severely limited by an inability to quantify spatiotemporal variations in C-14 reservoir age, or R(t), due to dynamic interplay between river runoff and marine water. Additionally, old carbon effects and species-specific behavioral processes also influence C-14 ages. Using the world's largest brackish water body (the estuarine Baltic Sea) as a test bed, combined with a comprehensive approach that objectively excludes both old carbon (using GIS) and species-specific C-14 effects, we demonstrate the use of Sr-87/Sr-86 ratios for quantifying R(t) in ubiquitous mollusc shell material, leading to almost an order of magnitude increase in Baltic Sea C-14 geochronological precision over the current state of the art. We propose that similar proxy methods can be developed for other brackish water bodies worldwide.
Place, publisher, year, edition, pages
2016. Vol. 43, no 2, 735-742 p.
IdentifiersURN: urn:nbn:se:uu:diva-283795DOI: 10.1002/2015GL066983ISI: 000372056400031OAI: oai:DiVA.org:uu-283795DiVA: diva2:921243
FunderSwedish Research Council