The radiocarbon dating laboratory is part of the Department of Earth Sciences, University of Waterloo. The natural level radio-isotope facility, built in the spring of 1974, was built primarily for dating groundwater and a combustion line for organic samples was added in 1975.

Measurements have continued with the same proportional counter system, pretreatment procedure, methane preparation and measurement, and calculation, as described previously (R, 1970, v 12, p 298–318). Uncertainties quoted are single standard deviations originating from standard, sample, and background counting rates. No 13C/12C ratios were measured. Sample descriptions have been prepared in cooperation with submitters.

Procedures and equipment have been described in previous date lists. Except as otherwise indicated, wood, charcoal and peat samples are pretreated with dilute NaOH–Na4P2O7 and dilute H3PO4 before conversion to the counting gas methane; marls and lake cores are treated with acid only. Very calcareous materials are treated with HCl instead of H3PO4. Pretreatment of bone varies with the condition of the bone sample, solid bone with little deterioration is first cleaned manually and ultrasonically. The bone is treated with 8% HCl for 15 minutes, then dilute NaOH–Na4P2O7 for 3 hours at room temperature, washed until neutral, and the collagen extracted by Longin's method (Longin, 1971). Charred bone is treated with dilute HCl, NaOH–Na4PO7, and then dilute HCl again.