The accelerator mass spectrometry facility at Seoul National University (SNU-AMS) began functioning in December 1998 and was first reported at the Vienna AMS conference in October 1999 and at the 17th Radiocarbon Conference in Israel in June 2000. At the Vienna conference, we reported our accelerator system (Kim et al. 2000) and the basic sample preparation system (Lee et al. 2000), including the combustion line to produce CO2 ; the catalytic reduction line for the graphitization of CO2 ; and also pretreatment procedures for wood, charcoal, and peat samples. Recent progress of the AMS facility (Kim et al. 2001) and extension of the sample pretreatment system to iron and bone samples were reported at the 17th Radiocarbon Conference (Cheoun et al. 2001). In the meantime, extensive testing of accuracy and reproducibility has been carried out, and ~1000 unknown archaeological and geological samples have been measured every year. A report of data carried out in 1999 is presented by Kim et al. (this issue). In this report, the archaeological, geological, and environmental data carried out in 2000 are presented in terms of yr BP.

Beavan Athfield (2006) has commented on our recent paper in this journal (Higham et al. 2005). In our opinion, both in her response and in Beavan Athfield (2004) she misrepresents the evidence and conclusions presented by Anderson (2000). She claims (Beavan Athfield 2006:117) that Andersons (2000) Figure 6, which is reproduced as Beavan Athfields (2004) Figure 1, shows that ages of ancient rat bone gelatin in 1995-1996 (NZA numbers 4000-6000) were exclusively earlier than about 1000 BP, while those from 1997 onward (NZA numbers 7000+) were exclusively later than about 1000 BP. Beavan Athfield asserts that this is the result of Anderson (2000) ignoring 9 published accelerator mass spectrometry (AMS) results from 1995-1996 that were younger than about 900 BP. These would be serious claims of poor scholarship, were they substantiated, but in fact, Anderson (2000, 2004) never asserted that the AMS results were distributed so exclusively, nor did he fail to take account of all published results.

Raqefet Cave (35 degrees 04'21"N, 32 degrees 39'17"W) is situated in the southeastern side of Mount Carmel in Israel (Figure 1) on the left bank of wadi Raqefet (230 m asl), ~50 m above the wadi bed. It is 50 m long with an area of ~500 m2 (Figure 2). Eric Higgs of Cambridge University and Tamar Noy of the Israel Museum conducted excavations at the site between 1970 and 1972 (Higgs et al. 1975). New excavations at the cave began in 2004 (Lengyel et al. 2005). Studies on the lithic archaeological remains from the 1970-1972 stratigraphic units assign Late Mousterian or Middle to Upper Paleolithic transition (layers VIII-VI in squares B-G/18-23), indeterminate early Upper Paleolithic (layer IV in squares B-G/18-23), Levantine Aurignacian (layers IV, III, and II in squares B-G/18-23), indeterminate late Upper Paleolithic (layer II in area B-G/18-23), Late Kebaran (layer I in squares B-G/18-23), Geometric Kebaran (layer VII in squares J-M/24-28), Late Natufian (layers IV-VI in squares A-H/7-17), Neolithic (I-IV in squares J-M/24-28), and Bronze Age (pits in squares A-H/7-17 and B-G/18-23) occupations (Higgs et al.1975; Lengyel 2003, 2005; Lengyel and Bocquentin 2005; Lengyel et al. 2005; Noy and Higgs 1971; Sarel 2004; Ziffer 1978a,b).

Within the framework of radioecological studies, 90Sr was determined in wheat grains, soil, and deposition samples. The radiochemical purification of 90Y consisted of liquid-liquid extraction by tributyl phosphate (TBP), followed by hydroxide and oxalate precipitations and, if necessary, the removal of thorium by anion exchange chromatography. The procedure proved to be very robust and reliable, having yttrium yields of 92.7 4.6% for 1-kg wheat samples, 90.9 4.2% for 50-g soil samples, and 90.6 3.2% for wet and dry deposition samples. 90Y was determined by Cerenkov counting and proportional counting. By optimizing the Cerenkov counting window, a figure of merit (FOM) of 4750 could be reached using a Quantulus 1220 system. Minimum detectable activities were in the range of 10 mBq.

Radiocarbon dates on samples aimed to date the settlement of Iceland are given together with comments by the laboratory, since many of the results and descriptions given by Sveinbjörnsdóttir et al. (2004) in Radiocarbon, together with new results, are in error. The intention of this paper is to present correct dates and further relevant information regarding samples used earlier and to discuss possible complications inherent in the method of Sveinbjörnsdóttir et al. (2004). Examples are given of how critical the collection, treatment, and interpretation of samples may be. An age difference between birch charcoal and grains for a site is expected due to various reasons. If the difference amounts up to ~100 yr, as reported by Sveinbjörnsdóttir et al. (2004), it must only to a small degree be due to biological age. Reference to an excavation report, details regarding stratigraphy, and discussions of the risk for displacement and contamination are missing in their paper. A final evaluation of the time for settlement should not be done until more research is completed and other possible or earlier suggested or even dated sites are discussed. A summary is given of the research on the island and volcanic effects on the 14C activity of the atmospheric CO2, especially over Iceland.

The Oxford Radiocarbon Accelerator Unit (ORAU) has used an ultrafiltration protocol to further purify gelatin from archaeological bone since 2000. In this paper, the methodology is described, and it is shown that, in many instances, ultrafiltration successfully removes low molecular weight contaminants that less rigorous methods may not. These contaminants can sometimes be of a different radiocarbon age and, unless removed, may produce erroneous determinations, particularly when one is dating bones greater than 2 to 3 half-lives of 14C and the contaminants are of modern age. Results of the redating of bone of Late Middle and Early Upper Paleolithic age from the British Isles and Europe suggest that we may need to look again at the traditional chronology for these periods.