This review of radiocarbon dates from northeastern Siberian Paleolithic sites provides data that can be applied to establishing a chronology of human settlement, and that can provide a rough estimate of the timing of the initial peopling of the New World.

Measurements of the stable isotope ratio 13C/12C, relative to PDB, were made for fractionation correction purposes on all oak samples used in the Irish oak 14C calibration curve. Stable isotope data have not been published previously. We have collated the stable isotope data from the calibration work, carried out some further measurements to investigate anomalies in the original results, and generated tables of data that include site and tree information pertaining to both stable isotopes and source material for 14C calibration measurements. The data suggest that land-grown trees tend to be isotopically lighter than bog-grown wood, and that the Irish trees used in the calibration exercise tend to be isotopically heavier than those from Scotland and England. Preliminary analysis of the data is given.

We describe applications of radiocarbon dating used for establishing a chronology of archaeological sites of the Novgorod region at the end of the first millennium ad. We have 14C-dated known-age tree rings from sites in Latvia and ancient Novgorod, northwest Russia, as well as charcoal and wood from Novgorod. Calendar ages of 14C-dated tree rings span the interval, ad 765–999. We used the Groningen calibration program, CAL15 (van der Plicht 1993) to calibrate 14C ages to calendar years. Comparisons between 14C results and archaeological data show good agreement, and enable us to narrow the calendar interval of calibrated 14C determinations.

We present here radiocarbon dates obtained using a liquid scintillation system installed at the Physical Research Laboratory (PRL), which has been in operation for the past three years for 14C measurements of oceanographic and geochemical samples from India.

The following list presents results of dating archaeological samples from Poland processed between 1979 and 1985. Three carbon dioxide-filled proportional counters (L1, L2 and L3) of different sizes were used for dating (Pazdur et al. 1982). Procedures for sample pretreatment, counting, statistical analysis and age calculations were essentially the same as previously described (Pazdur et al. 1982, 1985). All results are reported as conventional 14C dates in years before ad 1950. Unless explicitly stated, the results are not corrected for isotopic fractionation.

The prehistoric site Nahal Issaron is located on the alluvial fan of Nahal Issaron, a short wadi draining into Biqat Uvda some 50 km north of Eilat. Excavated in the early 1980s, it constitutes a major Pre-Pottery Neolithic B (PPNB) layer, with continued but sporadic occupation throughout the Late Neolithic to the Chalcolithic period. In the PPNB layer, a dense agglomeration of rounded, polygonal and rectangular structures was found, with courtyards and a variety of features such as hearths and ovens. The upper layer is badly preserved, apart from the hearths and ovens. Thirty samples from the site were 14C-dated in the Rehovot laboratory and five in the Pretoria laboratory. The results enabled a fine temporal resolution between layers and a refinement of the 7th through 5th millennium bc chronology. The dates also placed the sequence of changes in architecture and lithics within a more robust temporal framework, thus making the site a key chronological anchor in the Neolithic of Southern Israel, Sinai and Jordan.

Loess deposition within the Loess Plateau of China records the history of environmental change over the last 2.5 Myr. Loess-paleosol sequences of the last 10 ka, which have preserved information of global climate change, relate closely to human occupation of the area. Hence, studies of the deposition and development of Holocene loess are significant for studying environmental change and problems associated with engineering geology. We present here stratigraphic relations among four profiles from the south, west and center of the Loess Plateau. On the basis of 14C radiometric and AMS dates of organic material extracted from the paleosols, together with magnetic susceptibility measurements down each profile, we discuss Holocene stratigraphic divisions within the Loess Plateau, and suggest that the Holocene optimum, characterized by paleosol complexes, occurred between 10 and 5 ka bp. From 5 ka BP to the present, neoglacial activity is characterized by recently deposited loess.

The Xi'an Laboratory of Loess and Quaternary Geology has developed a small sample 14C dating facility consisting of a Wallac 1220 Quantulus™ liquid scintillation spectrometer, and a miniature benzene synthesis line based on the synthesis procedures used at the Australian National University (ANU). This line can produce ca. 0.3-ml benzene samples, which are then measured for 14C activity using 0.3-ml Teflon vials developed by Wallac Oy. The counting performance of the Quantulus™ spectrometer using 0.3-ml vials has been evaluated, and a potential age limit of ca. 45,000 BP has been obtained for samples containing up to 250 mg carbon. This dating facility fills the gap between large sample (2.4–6 g carbon) and microsample (<1 mg carbon) handling to form a 14C dating method sequence.

The following list presents results of dating archaeological samples from excavations in Africa. Most results reported in this list were obtained from 1982 to 1993 for international research projects studying the origin and early development of food-producing cultures in northeastern Africa, including the Nile basin and the Sahara. Detailed information on these projects may be found in the series of conference proceedings edited by Krzyżaniak and Kobusiewicz (1984, 1989, 1993).

A new automated pretreatment system for the preparation of materials submitted for accelerator mass spectrometry (AMS) analysis is less time-consuming and results in a higher sample yield. The new procedure was tested using two groups of plant fossils: one group was pretreated using the traditional method, and the second, using the automated pretreatment apparatus. We compared the time it took to complete the procedure and the amount of sample material remaining. The automated pretreatment apparatus proved to be more than three times faster and, in most cases, produced a higher yield. We also observed a darker discoloration of the KOH solutions, indicating that the automated system is more thorough in removing humates from the specimen compared to the manual method.

Many of the problems inherent with conventional 14C dating of lake and peat deposits are eliminated by AMS dating of pollen concentrates. Published work describes production of pollen concentrates through expulsion of most of the deposit matrix by repeated deflocculation, selective sieving and final retention of the largest subfossil pollen taxa. Less suited to pollen concentrate production are the highly organic peats and lake muds from the British Isles and Europe. In this study we tested the combined effectiveness of physical, chemical and microbiological degradation and elimination techniques for pollen concentrate production on highly organic peats and a lake mud. We also reviewed methods of enhancing concentrations of smaller sub-fossil pollen grains. Here we present a novel method of assessing AMS dating precision of pollen concentrates by comparing their calibrated dates with a volcanic event of known historical age.

In this list, we present 14C ages of archaeological, geological, hydrogeological, botanical and atmospheric samples measured since our previous list (Srdoč et al. 1992). Chemical pretreatment and counting techniques using a methane-filled proportional counter are essentially the same as reported earlier. Sample descriptions are prepared in collaboration with collectors and submitters.

The conventional 14C ages of 8 marine shells of known age and 11 marine shells stratigraphically associated with dated wood charcoal show considerable variation from expected ages. One source of this variation is seashore geology; comparison of 6 AMS dates on 3 species of shallow-water, herbivorous gastropod shells from Pleistocene limestone and Holocene volcanic coasts shows that shells from Pleistocene limestone coasts can have apparent, or reservoir, 14C ages up to 620 yr greater than shells of the same species from volcanic coasts. The relatively great variation in apparent ages of Hawaiian marine shells poses problems for their use in dating archaeological sites. For best results, an archaeological marine shell should be sourced to a particular local environment, and the apparent age of shells in that environment determined by dating well-provenienced shells of known age.

Twenty-seven 14C determinations from Aitutaki, southern Cook Islands inform on human settlement and Holocene coastal processes. I examine sedimentary, radiometric and archaeological data from Aitutaki with reference to regional evidence for a minor Holocene sea-level regression, which are in general agreement. Related processes of shoreline progradation and aggradation created near-shore environments conducive to human habitation, directly evidenced by ca. AD 900–1200. Nevertheless, biotic materials associated with this early cultural stratum suggest human colonization prior to this time. Archaeological preservation and recovery also may have been affected by changing sea level and related sedimentary processes.

Lakes Barrine and Eacham and their small, discrete, forested catchments are sites of intensive sedimentological, palynological and ecological research. The studies that we present here concentrate on integrating population statistics of tree species of the living forest with their histories, as documented by fine-resolution pollen analysis (Green and Dolman 1988). Most of the work has been undertaken at Lake Barrine, where the last 5 ka is recorded in laminated sediments. Additional information about these sites and about aspects of the project is contained in Chen (1986, 1987, 1988), Goodfield (1988), Grindrod (1979), Timms (1976, 1979) and Walker (1988).

The following list consists of dates for archaeological samples measured mostly between October 1989 and November 1990. Charcoal and grain samples were pretreated with 1M HC1 followed by washing in water and, in the majority of cases, with dilute alkali for the removal of humic acids. Wood samples were treated in the same way, or, if large enough, reduced to cellulose with chlorine dioxide produced in situ. Antler and bone samples were treated with cold dilute acid. We use the term “collagen” to mean the acid-insoluble organic fraction produced by this treatment rather than the true biochemical definition.