British Museum Natural Radiocarbon Measurements XIII

Abstract

The following list consists of dates for archaeologic samples mostly measured from July 1976 to December 1977. The dates were obtained by liquid scintillation counting of benzene using the laboratory procedures outlined in previous lists (see, eg, BM-VIII, R, 1976, v 18, p 16). Dates are expressed in radiocarbon years relative to ad 1950 based on the Libby half-life for 14C of 5570 yr, and are corrected for isotopic fractionation (δ13C values are relative to PDB). No corrections have been made for natural 14C variations (although in some instances approximate calibrated dates taken from the tables of R M Clark (1975) have been given in the comments where this aids interpretation of results). The modern reference standard is NBS oxalic acid (SRM 4990). Errors quoted with the dates are based on counting statistics alone and are equivalent to ± 1 standard deviation (± 1σ), Dates in this and the next list (BM-XIV) reported to submitters or published elsewhere before the introduction of the new guidelines for rounding of computed figures have deliberately been left unrounded. From BM-XV onwards all BM dates will be rounded before publication in conformity with the recently recommended procedures (R, 1977, v 19, p 362). Descriptions, comments, and references to publications are based on information supplied by submitters.