Four samples from Tell Brak were analysed for radiocarbon content at the British Museum Research Laboratory in 1987, with the results given below (Ambers et al., 1989). All results are quoted in the form recommended by Stuiver and Polach (1977) in uncalibrated years BP (before 1950) and corrected for measured δ13C variation. Calibrations are given based on 1σ error terms, following the curves of Pearson and Stuiver (1986) and Pearson et al. (1986), using Method A of revision 2.0 of the University of Washington Quaternary Laboratory Radiocarbon Calibration Program (Stuiver and Reimer 1986), and are quoted in the form recommended in Mook (1986); the end points of the calibrated date ranges have been rounded to the nearest five years.

Three of the samples (BM-2554, -2555, -2556), all of charcoal, were treated with dilute acid and alkali to remove contamination. A single grain sample from context CH 450 was separated into humic and humin fractions, which were measured independently. All samples were analysed by conventional liquid scintillation counting. Errors quoted are the counting error for the sample combined with an estimate of the errors contributed by the modern and background samples. This estimate includes both counting and non-counting errors, the latter being computed from differences in the overall count-rates observed among the individual backgrounds and moderns.