The Impact of Leaching on Radiocarbon Ages of Small-sized Foraminifera Samples


Contact
Hendrik Grotheer

Abstract

Reliable radiocarbon (14C) ages of foraminifera are a prerequisite to generate robust high-resolution age-depth models or to obtain precise understanding of past carbon cycle dynamics. With the advance of small-scale 14C measurements, instrumental precision and levels of contamination (extraneous carbon introduced during sample pretreatment or analysis) became increasingly important to consider. To reduce the effect of carbon contamination, an attempt can be made to remove it by leaching the surface with weak acids. Alternatively, mathematical corrections (e.g., subtraction) based on processing blanks can be applied. We report on 14C analyses of monospecific foraminifera samples compared between different blank corrections (correction against 14C-free CO2, IAEA-C1 and foraminifera) and sample treatments (i) to examine whether chemical pretreatment and mathematical blank subtraction are comparable, and (ii) to determine limitations hindering reliable 14C dating with ever smaller sample sizes. The data show that chemical pretreatment of foraminifera corrected against IAEA-C1 does remove surface contamination and that the same effect can be achieved for untreated samples that were mathematically corrected for blank values determined from sample size-matched 14C-free foraminifera. Leaching only has a beneficial effect on 14C data for older samples, where the isotopic difference between untreated and chemically pretreated samples exceeds the analytical precision.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
59528
DOI 10.1017/rdc.2022.96

Cite as
Grotheer, H. and Mollenhauer, G. (2023): The Impact of Leaching on Radiocarbon Ages of Small-sized Foraminifera Samples , Radiocarbon, 65 (1), pp. 121-133 . doi: 10.1017/rdc.2022.96


Download
[thumbnail of Grotheer and Mollenhauer 2023 Radiocarbon.pdf]
Preview
PDF
Grotheer and Mollenhauer 2023 Radiocarbon.pdf - Other

Download (567kB) | Preview

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Citation


Actions
Edit Item Edit Item