Radiocarbon dating provides the principal chronometric data for the Middle and Upper Palaeolithic, Epipalaeolithic, and Chalcolithic periods in the southern Levant. It is a secondary source of dating evidence for the Early Bronze age, when archaeological correlations with Syria and especially Egypt become available. For the Middle and Late Bronze age, Iron age, Persian, Hellenistic, Roman, and Byzantine periods, 14C dating has only limited value because the technique is less precise than the normally available archaeologic and historic materials.

This list consists of dates of soil samples from selected soil profiles in Tunisia, Sudan, and Argentina. The profiles from Tunisia were taken to elucidate ages of typic paleosols of paleoclimatic significance. The Sudan profiles increase our understanding of pedogenesis of Sudanese Vertisols. The existence of pedoturbation in these profiles is further explored and questioned. The profiles of Argentina were dated to supplement information from chemical and micromorphological studies.

This list contains the results of 14C determinations obtained at the laboratory in 1982–1983.

Most of the 14C measurements reported here were made between October 1982 and October 1983. Equipment, measurement, and treatment of samples are as reported previously (R, 1968, v 10, p 36–37; 1976, v 18, p 290; 1980, v 22, p 1045).

Age calculations are based on a contemporary value equal to 95% of the activity of NBS oxalic acid standard (No. 4990A) and on the conventional half-life for 14C of 5568 yr. Results are reported in years before 1950 (years bp). Errors quoted with the dates are based on counting statistics alone and are equivalent to ± 1 standard deviation (±σ).

The following list includes radiocarbon analyses of samples related to studies of Holocene sea levels completed since the publication of the last list (R, 1980, v 22, p 1073–1083). Sample preparation and counting for liquid scintillation samples remain the same. However, an additional gas-proportional facility was added in 1981 to handle the analyses of small samples, some of which are included in this list. The new system consists of two 660cc OFHC copper counters built at Queens College. Samples are counted over at least two 2800 minute intervals alternating with backgrounds and standards counted over 1400 minute intervals. Ages are based on the Libby half-life of 5568 years and include 1σ standard deviations of sample, standard, and background activities.

This list reports measurements made on archaeologic and geologic samples by our laboratory from June 1982 to December 1983. Results of measurements made during that period which lack review by submitters will be reported in a subsequent date list. Sample preparation techniques and benzene synthesis remain as described previously (R, 1982, v 24, p 344–351). For low organic samples, such as sediments, we now use a combustion tube assembly. These samples are burned under oxygen flow in a quartz tube. To absorb sulfur and break up nitrous compounds, we pass combustion gases through a 50% mixture of MnO2 and CuO wire heated to ca 500°C. The gas is then bubbled through a distilled water and KMnO4 solution to remove chlorides before being introduced into our standard dry ice and CO2 traps.

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. No 13C/12C ratios were measured. Sample descriptions have been prepared in cooperation with submitters.

The following radiocarbon date list contains dates of samples measured since our previous list (R, 1982, v 24, p 352–371). As before, age calculations are based on the Libby half-life (5570 ± 30) yr and reported in years before 1950. The modern standard is 0.95 of the NBS oxalic acid activity. Sample pretreatment, combustion, and counting technique are essentially the same as described in R, 1971, v 13, p 135–140, supplemented by new techniques for groundwater processing (R, 1979, v 21, p 131–137).