Towards radiocarbon dating of single foraminifera with a gas ion source

• Verfasst von: Wacker, Lukas [VerfasserIn]
• Verfasst von: Lippold, Jörg [VerfasserIn]
• Verfasst von: Molnár, M. [VerfasserIn]
• Verfasst von: Schulz, H. [VerfasserIn]
• Titel: Towards radiocarbon dating of single foraminifera with a gas ion source
• Verf.angabe: L. Wacker, J. Lippold, M. Molnár, H. Schulz
• E-Jahr: 2013
• Jahr: January 2013
• Umfang: 4 S.
• Teil: volume:294
• Teil: year:2013
• Teil: pages:307-310
• Teil: extent:4
• Fussnoten: Available online 20 September 2012 ; Gesehen am 28.07.2021
• Titel Quelle: Enthalten in: Nuclear instruments & methods in physics research / B
• Ort Quelle: Amsterdam [u.a.] : Elsevier, 1984
• Jahr Quelle: 2013
• Band/Heft Quelle: 294(2013), Seite 307-310
• ISSN Quelle: 1872-9584
• DOI: doi:10.1016/j.nimb.2012.08.038
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Accelerator mass spectrometry
• Sach-SW: AMS
• Sach-SW: Carbonates
• Sach-SW: Foraminifera
• Sach-SW: Gas ion source
• Sach-SW: Radiocarbon
• K10plus-PPN: 1764807197

Abstract

Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO2 is liberated from 150 to 1150μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400μg (50μgC) typically gives a 12C− ion source current of 10-15μA over 20min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560μg Cibicides pseudoungerianus test at 14,030±160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.