High-Precision AMS 14C Results on TIRI/ FIRI Turbidite

Abstract

Unleached aliquots of TIRI/FIRI turbidite were analyzed by accelerator mass spectronomy (AMS) over a timespan of 18 months. Individual analyses ranged from 18,090-18,245 yr BP with reported errors between 30-50 yr. The weighted average fraction modern (FM) of these 28 measurements is 0.10378 +/0.00008 (which equates to 18,199 +/8 yr BP) and the measurements show a 1 standard deviation scatter of 0.00044 (+/35 yr). The fractional error of these results indicates reproducibility of individual measurements at the 4 per mil (1-sigma) level, which is consistent with the quoted counting-statistics-based errors. Laboratories engaged in the determination of 14C results at reasonably high precision should consider taking advantage of the TIRI and FIRI sample materials in the role of process standards. Additional suites of high-precision data are necessary to refine the accuracy of these sample materials.