High-precision AMS (super 14) C 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 + or - 0.00008 (which equates to 18,199 + or - 8 yr BP) and the measurements show a 1 standard deviation scatter of 0.00044 (+ or -35 yr). The fractional error of these results indicates reproducibility of individual measurements at the 4 per mil (1sigma ) level, which is consistent with the quoted counting-statistics-based errors. Laboratories engaged in the determination of (super 14) C 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.