Using Stable Carbon Isotopes to Quantify Radiocarbon Reservoir Age Offsets in the Coastal Black SeaAbstract

TitleUsing Stable Carbon Isotopes to Quantify Radiocarbon Reservoir Age Offsets in the Coastal Black SeaAbstract
Publication TypeJournal Article
Year of Publication2019
AuthorsSoulet, G, Giosan, L, Flaux, C, Galy, V
JournalRadiocarbon
Volume61
Issue1
Pagination309 - 318
Date PublishedJan-02-2019
ISSN0033-8222
KeywordsBlack Sea, Carbon cycle, freshwater reservoir effect, Geochronology, Reservoir age
Abstract

Constraining radiocarbon (C-14) reservoir age offsets is critical to deriving accurate calendar-age chronologies from C-14 dating of materials which did not draw carbon directly from the atmosphere. The application of C-14 dating to such materials is severely limited in hydrologically sensitive environments like the Black Sea because of the difficulty to quantify reservoir age offsets, which can vary quickly and significantly through time, due to the dynamics of the biogeochemical cycling of carbon. Here we reconstruct C-14 reservoir age offsets (Rshell-atm) of Holocene bivalve shells from the coastal Black Sea relatively to their contemporaneous atmosphere. We show that the C-14 reservoir age offset and the stable carbon isotope composition of bivalve shells are linearly correlated in this region. From a biogeochemical standpoint, this suggests that inorganic stable carbon isotope and C-14 compositions of Black Sea coastal waters are controlled by the balance between autochthonous primary productivity and heterotrophic respiration of allochthonous pre-aged terrestrial organic matter supplied by rivers. This provided an important implication for Black Sea geochronology as the reservoir age offset of C-14-dated bivalve shell can be inferred from its stable carbon isotope composition. Our results provide a fundamental and inexpensive geochemical tool which will considerably improve the accuracy of Holocene calendar age chronologies in the Black Sea.

URLhttps://www.cambridge.org/core/product/identifier/S0033822218000619/type/journal_articlehttps://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033822218000619
DOI10.1017/RDC.2018.61