ABSTRACTS PLENARY ORAL SESSIONS Plenary Session 1: Radiocarbon and Archaeology #1 RADIOCARBON DATING THE DISPERSAL OF THE FIRST ANATOMICALLY MODERN HUMANS INTO WESTERN EUROPE

Tom Higham1, Roger Jacobi2, Laura Basell1, Rachel Wood1, Katerina Douka1, Christopher Bronk Ramsey1 1. Oxford Radiocarbon Accelerator Unit, RLAHA, University of Oxford, Oxford. 2. The British Museum, London.

A reliable chronology is one of the keys to understanding the nature of the transition from the Middle to Upper Paleolithic in western Eurasia. The transition describes the period during which anatomically modern humans (AMHs) replaced Neanderthals—who ultimately became extinct. The period over which this took place and the length of the temporal overlap between the two groups is a central question concerning researchers in this field with wide-ranging implications in a number of areas; for example, the cognitive abilities of Neanderthals and whether there was any genetic exchange between the two populations. Within a large project funded by the NERC in the UK, we have been dating over 300 samples of bone, shell and charcoal from more than 50 key Paleolithic sites in over 10 countries. The main focus has been on sites with a succession of contexts containing lithic industries attributed to the Mousterian, Uluzzian, Châtelperronian (all associated with Neanderthals), Aurignacian and Gravettian (associated with AMHs). Work undertaken in Oxford over the last decade has been aimed at improving the dating of material between ~25–55 kyr BP, which covers the Middle–Upper Paleolithic transition. We have developed aspects of our pretreatment chemistry, particularly the purification of bone collagen using ultrafiltration. When comparing the ultrafiltered results with previously determined samples of the same bone from our laboratory, and other laboratories, the results in many cases are quite different. When ultrafiltration is used, the dates are often older, and we consider, more accurate. We are also applying ABOx-SC methods to samples of charcoal, which shows similar improvements in many cases. In tandem, work has been undertaken on improving the applicability of our background correction for bone (Wood et al., this conference). In addition, we have been refining the detection of trace calcite in samples of marine shell for radiocarbon dating (Douka et al., this conference). In this paper, we will discuss the emerging chronology for the dispersal of the earliest anatomically modern humans into Europe by presenting results from some of the key sites in France, Germany, Italy, Spain, and Belgium.

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#2 RADIOCARBON DATING OF THE FIRST EUROPEAN MODERN HUMANS: NEW DIRECT AMS DATES OF AURIGNACIAN SHELL ORNAMENTS

Katerina Douka1, Robert E M Hedges1, Thomas F G Higham2 1. Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK. 2. Oxford Radiocarbon Accelerator Unit, Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK.

There are two principal hypotheses for the dispersal of the first anatomically modern humans (AMH) into Europe. The first posits an initial movement along the Danubian corridor into north and central Europe, while the second concerns a “southern dispersal” along the Mediterranean Rim. Resolving which of the two is more likely is dependent upon a reliable radiocarbon chronology, which, at present, is lacking. We have investigated over 20 sites in southern Europe containing the Aurignacian, an Upper Paleolithic culture closely associated with the first AMH in Europe. Unfortunately, the survival of bone collagen, our preferred material for analysis, is severely compromised, because of low survival of proteins remaining. In the light of this, we have sought to date perforated shell ornaments from these sites. In doing so, the main problems to overcome are: 1) the removal of contaminants from the carbonate; 2) the calculation of the marine reservoir effect; and 3) uncertainty regarding the possibility of old, fossil shell being used for manufacturing ornaments. The first problem has been addressed (see Douka et al., this conference) by developing a novel density separation method for removing calcite contamination and the application of high-precision XRD for improved detection of calcite in the shell samples. The second is difficult to quantify, but is probably less significant owing to the proportionally lower effect of the marine offset when analyzing material of this age. The final problem has been addressed by others examining the time-averaging of naturally forming shell beds along coastal margins, which shows that “fossil” shells although present tend to be rare thus unlikely to be selected by the AMH. Initial results from several of the key sites that date to this period will be presented. In some instances, we are able to gauge the success of the approach by comparing the results against the known-age Campanian Ignimbrite tephra of 39.3 kyr BP. There are important implications for our understanding of the dynamics of the initial dispersal of modern humans and the concomitant decline of Neanderthal populations, which occurred during the same period.

#3 IS MORE PRECISE DATING OF PALEOINDIAN EXPANSION FEASIBLE?

Stuart J Fiedel1 and Yaroslav V Kuzmin2 1. Louis Berger Group, Richmond, VA 23219, USA. 2. Institute of Geology & Mineralogy SB RAS, Novosibirsk 630090, Russia.

Recent efforts to precisely date the florescence of the Clovis culture have been hampered by both practical and theoretical problems. These include: 1) The era of Clovis expansion (ca. 11,200– 10,700 BP, or 13,200–12,700 cal BP) coincides with the gap between the anchored Central European tree-ring sequence (back to 12,400 cal BP) and the floating Bølling–Allerød sequence; 2) Clovis seems to immediately precede the onset of the Younger Dryas (YD) stadial. The “black mats” of

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the US Southwest appear to mark the regional occurrence of this climatic downturn. However, the timing and means of long-distance propagation of this climatic event are not yet well understood. Greenland ice cores (GISP2, GRIP, and NGRIP) remain poorly synchronized, with a discrepancy of 100 to 250 years for the date of onset (as late as 12,700 cal BP, or as early as 12,950 cal BP); 3) The YD onset was accompanied by a rapid drop of 14C ages from 11,000 to 10,600 BP in less than a century. The mechanism causing this was probably a change in overturning circulation in the North Atlantic. Do variable Clovis ages, often from what appear to be single-occupation contexts, reflect this “cliff” effect, slightly earlier minor reversals during the late Allerød, or simply the practical limitations of precision of the radiocarbon method? 4) Dates for Fishtail or Fell I sites (with fluted, stemmed points) in southern South America are statistically indistinguishable from Clovis dates in North America. Does this imply very rapid population expansion, diffusion of toolmaking techniques through long-established local populations (as argued by Waters and Stafford 2007), or abnormally large inter-hemispheric radiocarbon offsets? 5) Are recent ostensibly high-precision collagen-derived dates for Paleoindian-associated fauna (e.g. horse, mammoth) reliable? Are inter-lab blind tests of the new filtration processes necessary? These issues will be considered at the meeting. Reference: Waters MR, Stafford Jr. TW. 2007. Science 315:1122–6.

#4 THE IMPACT OF NEW RADIOCARBON PRETREATMENT TECHNIQUES FOR UNDERSTANDING THE IBERIAN MIDDLE TO UPPER PALEOLITHIC TRANSITION

R E Wood and T F G Higham ORAU, University of Oxford.

The Iberian Middle to Upper Paleolithic transition—the period in which anatomically modern human populations replace Neanderthal populations—has long held intense interest within the archaeological community. In the south of the peninsula, radiometric and archaeological evidence currently suggests that Neanderthals may have survived until the Last Glacial Maximum, that is, around 10,000 years after the arrival of modern humans in the northern Cantabrian and Catalonian regions. This makes southern Iberia the largest and most securely identified Neanderthal refugium in Europe. This has profound effects on understanding the cognition of Neanderthals, the possibility and nature of the interaction between the two species, and their response to environmental change. However, given that the desert-like southern regions suffer from particularly poor organic preservation and that contamination is most likely to produce erroneously young ages, numerous authors have rejected all late Neanderthal radiocarbon dates. They suggest instead that the southern part of the peninsula was abandoned and empty of any hominins while modern humans were denizens of the northern regions. The difficulty in assessing whether many of the radiocarbon dates are reliable from the published information, both from a chemical and an archaeological perspective, means that the debate cannot proceed without the construction of new chronologies. This paper presents initial results from a study aiming to re-date key Iberian sites and fossils by dating bone (using ultrafiltration preparative methods) and charcoal (using the ABOx-SC protocol). Initial results will be presented from several key sites.

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#5 ON THE ACCURACY OF RADIOCARBON DATING FOR THE NEOLITHIC

A Shukurov1, P M Dolukhanov2, D D Sokoloff3 1. School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, UK. 2. School of Historical Studies, Newcastle University, Newcastle upon Tyne NE1 7RU, UK. 3. Department of Physics, Moscow State University, Moscow 119992, Russia.

The accuracy of radiocarbon dating for Neolithic sites in Europe and the Near East is assessed using selected, well-explored sites with a statistically large number of 14C age determinations. We select those sites where we have reasons to believe that each represents a relatively short-lived archaeological event. Among the sites discussed are Razdorskoe 2 (Mesolithic-Neolithic transition, ca. 7000 cal BC, southern Russia), Brunn am Gebirge (LBK, ca. 5273 cal BC, Austria), Serteya 2 (Zhizhitsian, late Neolithic–Early Bronze Age, ca. 2300 cal BC, northwestern Russia), together with 7 other sites. The dates from Serteya 2 are tree-ring age determinations from a single pile-dwelling structure; those from Razdorskoe belong to a single hearth. The selected date sequences are used to calculate the empirical dispersion of the calibrated dates, which is surprisingly similar in all cases, ranging from 83 years for Serteya 2 and 99 years for Brunn am Gebirge to 214 years for Razdoskoe 2. This scatter can be attributed to various effects affecting the 14C content of the sample, e.g. contamination by younger and older carbon, various systematic errors, etc. We suggest that the intrinsic accuracy of 14C dating for the period is 100–200 years regardless of the dating technique (AMS versus conventional). It is natural to expect that the intrinsic accuracy varies with epoch and location, but more detailed studies are required to identify such trends.

Plenary Session 2: Calibration #6 14C

CALIBRATION IN THE 2ND AND 1ST MILLENNIUM BC – EASTERN MEDITERRANEAN RADIOCARBON COMPARISON PROJECT

B Kromer1, S Manning, M Friedrich, S Talamo 1. Heidelberg Academy of Sciences, INF 229, Heidelberg, Germany, D-69120, Germany.

Radiocarbon calibration in the 2nd and 1st millennium BC is of crucial importance to address ongoing disputes between archaeology and 14C dating, such as the date of the Santorini eruption and the dating of key sites in the Aegean and Near East regions in the Late Bronze Age. In the Eastern Mediterranean Radiocarbon Comparison Project (EMRCP), we remeasured German oak samples in 5and 10-year increments for several intervals in the 2nd and 1st millennium BC. As noted before, some of the observed variance of the 14C dates appears to result from fluctuations of the atmospheric 14C level and it is suppressed to some extent in IntCal04. We report on the wiggle-match of the floating Bronze Age juniper chronology of Gordion to our new German oak data and to the calibration data sets of IntCal04 and IntCal98.

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#7 COMPARISON OF TERRESTRIAL AND MARINE ARCHIVE Δ14C VARIATION DURING MARINE ISOTOPE STAGE 3

Warren Beck1, David Richards2, Dirk Hoffmann2, Peter Smart2, Joy Singarayer2, George Burr1, Tricia Kretchmark1, Michelle Felton2, Paul Valdes2, Andy Ridgewell2 1. NSF-Arizona AMS Facility, PAS Building 81, University of Arizona, Tucson, AZ 85721, USA. 2. BRIDGE, School of Geographical Sciences, University of Bristol, University Rd., Clifton, Bristol, BS3 1DD, UK.

Since 1990 a great deal of effort has been dedicated to expanding the record of atmospheric Δ14C variations beyond the limit of the tree-ring calibration using hybrid records based on corals, stalagmites, forams, and terrestrial macrofossils. Large discrepancies observed between some of these records has prevented their combined use to formulate a unified calibration curve, though various subsets of these data are now being used as the basis of several independent, and by some measures, inconsistent radiocarbon calibrations. In the absence of convincing evidence from the terrestrial realm, nearly all of these rely heavily on marine data to constrain atmospheric Δ14C by adopting model assumptions about past changes in the marine reservoir age at specific site locations. Here we investigate the extent to which Δ14C records based on speleothems from the terrestrial realm can be compared with Δ14C records from the marine realm to inform our understanding of carbon exchange between the ocean and atmosphere during marine isotope stage 3. Using an earth-system model (GENIE) to elucidate likely past changes in marine reservoir effect, we find that the Atlantic and Pacific basins significantly differ in their response for periods of rapid ocean circulation change such as the Younger Dryas. These findings have implications for the reconstructed atmospheric Δ14C record. Secondly, while we recognize that estimates of Δ14Catm using speleothems suffer from a source of uncertainty analogous to the marine reservoir age for corals and forams, the Δ14C pattern revealed by the Bahamas speleothems and Cariaco Basin records[1] (the later adjusted to the most recent Greenland ice core chronology[2]) are now in broad agreement. GENIE model results for marine isotope stage 3 using the GLOPIS-75[3] geomagnetic intensity record, are also substantially in agreement with these records, indicating that production rate changes dominate the temporal pattern of 14C concentration during this time. [1] Hughen et al. (2006) Quaternary Science Reviews 25:3216–3227. [2] Andersen et al. Clim. Past 3, 1235–1260. [3] Laj et al. (2004) In: Timescales of the Paleomagnetic Field.

#8 SUIGETSU 2006: A WHOLLY TERRESTRIAL RADIOCARBON CALIBRATION CURVE

R A Staff1, C Bronk Ramsey1, C Bryant2, F Brock1, H Lamb3, M Marshall3, A Brauer4, G Schlolaut4, P Tarasov5, R Payne6, E Pearson6, Y Yokoyama7, J Tyler7, T Haraguchi8, K Gotanda9, H Yonenobu10, T Nakagawa6, Suigetsu 2006 Project Members 1. Research Laboratory for Archaeology and the History of Art, University of Oxford, UK. 2. NERC Radiocarbon Laboratory, SUERC, East Kilbride, UK. 3. Institute of Geography and Earth Sciences, University of Wales Aberystwyth, UK. 4. GeoForschungsZentrum, Potsdam, Germany. 5. Department of Earth Sciences, Freie Universität, Berlin, Germany.

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6. Department of Geography, University of Newcastle-upon-Tyne, UK. 7. Department of Earth and Planetary Sciences, University of Tokyo, Japan. 8. Department of Geosciences, Osaka City University, Japan. 9. Faculty of Policy Informatics, Chiba University of Commerce, Japan. 10. College of Education, Naruto University of Education, Japan.

Lake Suigetsu, Honshu Island, central Japan (35°35’N, 135°53’E) provides an ideal sedimentary sequence from which to derive a wholly terrestrial radiocarbon calibration curve back to the limits of radiocarbon detection (ca. 60 cal kyr BP). The presence of well-defined, annually-deposited laminae (varves) throughout the entirety of this period provides an independent, high-resolution chronometer from which radiocarbon measurements of plant macrofossils from the sediment column can be directly related. The importance of this site for radiocarbon calibration purposes was brought to the attention of the community through the works of Kitagawa and van der Plicht (1998a, 1998b, 2000). However, data from this initial Lake Suigetsu project were found to diverge significantly from alternative, marine-based calibration data sets released soon thereafter (e.g. Beck et al. 2001; Hughen et al. 2004). The reasons for such divergence lie in the absolute age chronology of the initial Suigetsu project – the result of both missing sections of the retrieved sedimentary column, as well as varve counting uncertainties. Lake Suigetsu was re-cored in summer 2006, with material obtained from four separate bore-holes, producing a composite core of 73.19 m length, lacking any of the age gaps of the former study. The purpose of the present paper is therefore to refresh the community’s knowledge of the Lake Suigetsu site; to discuss the multi-disciplinary techniques being utilized to derive both chronological (Schlolaut et al., this conference) and paleoenvironmental data from throughout the sedimentary profile; and to demonstrate the AMS radiocarbon results thus far obtained from the Suigetsu 2006 project. Beck JW, Richards DA, Edwards RL, Silverman BW, Smart PL, Donahue DJ, Hererra-Osterheld S, Burr GS, Calsoyas L, Jull AJT, Biddulph D. 2001. Extremely large variations of atmospheric 14C concentration during the Last Glacial period. Science 292:2453–2458. Hughen K, Lehman S, Southon J, Overpeck J, Marchal O, Herring C, Turnbull J. 2004. 14C activity and global carbon cycle changes over the past 50,000 years. Science 303:202–207. Kitagawa H, van der Plicht J. 1998a. Atmospheric radiocarbon calibration to 45,000 yr B.P.: Late Glacial fluctuations and cosmogenic isotope production. Science 279:1187–1190. Kitagawa H, van der Plicht J. 1998b. A 40,000-year varve chronology from Lake Suigetsu, Japan: extension of the 14C calibration curve. Radiocarbon 40(1):505–515. Kitagawa H, van der Plicht J. 2000. Atmospheric radiocarbon calibration beyond 11,900 cal BP from Lake Suigetsu laminated sediments. Radiocarbon 42(3):369–380.

#9 ASSESSMENT OF THE INTEGRITY OF THE SOUTHERN HEMISPHERE 14C CALIBRATION CURVE AND ITS EXTENSION FROM AD 785 TO 195 BC, WITH PARTICULAR EMPHASIS ON THE INTERHEMISPHERIC OFFSET

Alan Hogg1, Jonathan Palmer2, Gretel Boswijk3, Christopher Bronk Ramsey4, Chris Turney5, Gerry McCormac6, David Brown6 1. Radiocarbon Laboratory, University of Waikato, PB 3105, Hamilton 3240, New Zealand. 2. Gondwana Tree-Ring Laboratory, P.O. Box 14, Little River, Canterbury 7546, New Zealand. 3. School of Geography & Environmental Science, University of Auckland, PB 92019, Auckland, New Zealand.

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4. Oxford Radiocarbon Accelerator Unit, Research Lab for Archaeology, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK. 5. School of Geography, Archaeology and Earth Resources, University of Exeter, Devon EX4 4RJ, UK. 6. Centre for Climate, the Environment & Chronology (14CHRONO), School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, Northern Ireland BT7 1NN, UK.

Numerous studies show a measurable difference in Δ14C in wood from trees growing in the same year in opposite hemispheres. Although this interhemispheric offset was assumed to be constant in time, duplicate high-precision Δ14C measurements on contemporaneous Southern Hemisphere (SH) and Northern Hemisphere (NH) sample pairs from AD 955–1845 demonstrate that it is variable, with SH wood 8–80 14C years older during this interval. The SH atmospheric 14C calibration curve, SHCal04, consists of a measured phase (AD 955–1955) and a modeled phase (the remainder of the Holocene), with the latter based upon the NH curve, IntCal04, with an applied variable offset (based upon that observed from AD 955–1845) generated by a random effects model. We present >100 high-precision 14C measurements on decadal samples of dendrochronologicallydated New Zealand kauri to extend the measured phase of SHCal04 and to test the integrity of the modeled phase between AD 785–195 BC. The interhemispheric offset is investigated in this interval with 15 high-precision 14C measurements on selected paired decadal samples of dendrochronologically-dated Irish oak (Quercus petraea). Five decadal samples (AD 955–995) overlap with the measured phase of SHCal04 for QA purposes. We also introduce a new method for assessing published SH Holocene data sets to determine their usefulness in estimating the offset for these earlier time periods. Our kauri measurements are in very close agreement where they overlap with the measured phase of SHCal04 and with the modeled phase of SHCal04 from AD 785–195 BC and confirm the integrity of SHCal04 for this period. The kauri-oak decadal sample pairs indicate a continuance of the interhemispheric offset, which averages 27–58 years for the measured intervals. We show that many of the published SH Holocene data sets are too imprecise to detect an offset of this magnitude.

#10 DEVELOPMENTS IN THE CALIBRATION AND MODELING OF RADIOCARBON DATES

C Bronk Ramsey1, M Dee1, S Lee1, T Nakagawa2, R A Staff1, Suigetsu 2006 Project Members 1. Research Laboratory for Archaeology & the History of Art, University of Oxford, UK. 2. Department of Geography, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.

Calibration is a core element of radiocarbon dating and is undergoing rapid development on a number of different fronts. This is most obvious in the area of radiocarbon archives suitable for calibration purposes, which are now demonstrating significantly greater coherence over the earlier age range of the technique. Of particular significance to this end are the development of purely terrestrial archives such as those from the Lake Suigetsu sedimentary profile (Staff et al., this conference) and kauri tree rings from New Zealand, in addition to the groundwater records from speleothems. Equally important, however, is the development of statistical tools that can be used with, and develop, such calibration data. In the context of sedimentary deposition, age-depth modeling provides a very useful way to analyze series of measurements from cores, with or without varve information. New methods are under development, making use of model averaging, that generate more

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robust age models. In addition, all calibration requires a coherent approach to outliers, for both single samples and where entire data sets might be offset relative to the calibration curve. This paper will look at current developments in these areas.

#11 PROGRESS IN THE EXTENSION AND UPDATE OF THE INTCAL04, MARINE04, AND SHCAL04 RADIOCARBON CALIBRATION CURVES

P J Reimer1, M G L Baillie1, E Bard2, A Bayliss3, J W Beck4, M Blaauw1, P G Blackwell5, C Bronk Ramsey6, C E Buck5, G S Burr4, R L Edwards7, M Friedrich8,9, P M Grootes10, T P Guilderson11,12, I Hajdas13, T J Heaton5, A G Hogg14, K A Hughen15, K F Kaiser16,17, B Kromer9, F G McCormac1, S W Manning18, R W Reimer1, D A Richards19, J R Southon20, S Talamo21, F W Taylor22, C S M Turney23, J van der Plicht24,25, C E Weyhenmeyer26 1. 14CHRONO Centre for Climate, the Environment and Chronology, School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, Belfast BT7 1NN, UK. 2. CEREGE, UMR-6635, Europole de l’Arbois BP80, 13545 Aix-en-Provence cdx 4, France. 3. English Heritage, 23 Savile Row, London W1S 2ET, UK. 4. Department of Physics, University of Arizona, Tucson, AZ 85721, USA. 5. Department of Probability and Statistics, University of Sheffield, Sheffield S3 7RH, UK. 6. Research Laboratory for Archaeology and the History of Art, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK. 7. Department of Geology and Geophysics, University of Minnesota, MN 55455-0219, USA. 8. Institut für Botanik-210, D-70593 Stuttgart, Germany. 9. Heidelberger Akademie der Wissenschaften, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany. 10. Leibniz Laboratory, Christian-Albrechts-Universität zu Kiel 24098, Germany. 11. Center for Accelerator Mass Spectrometry L-397, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. 12. Ocean Sciences Department, University of California-Santa Cruz, Santa Cruz, CA 92697, USA. 13. Labor für Ionenstrahlphysik, ETH, 8092 Zurich, Switzerland. 14. Radiocarbon Dating Laboratory, University of Waikato, Private Bag 3105, Hamilton, New Zealand. 15. Woods Hole Oceanographic Institution, Department of Marine Chemistry & Geochemistry, Woods Hole, MA 02543 USA. 16. Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zurcherst. 111, 8903 Birmensdorf, Switzerland. 17. Department of Geography, University of Zurich-Irchel, 8057 Zurich, Switzerland. 18. Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology, Cornell Tree Ring Labora tory, Cornell University, Ithaca, NY 14853, USA. 19. School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK. 20. Department of Earth System Science, University of California-Irvine, Irvine, CA 92697, USA. 21. Max Planck Institute for Evolutionary Anthropology, Department of Human Evolution, Deutscher Platz 6, D-04103 Leipzig, Germany. 22. Institute for Geophysics, University of Texas, Austin, TX 78758-4445, USA. 23. School of Geography, Archaeology and Earth Resources, University of Exeter, Exeter EX4 4QJ, UK. 24. Centrum voor Isotopen Onderzoek, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands. 25. Faculty of Archaeology, Leiden University, P.O.Box 9515, 2300 RA Leiden, Netherlands. 26. Department of Earth Sciences, Syracuse University, Syracuse, NY 13244-1070 USA.

There are currently few purely atmospheric 14C calibration archives with absolutely known calendar ages beyond the end of the European tree-ring chronologies; however, earth scientists and archaeologists need to estimate calendar age ranges throughout the radiocarbon dating range. The IntCal Working Group plans to provide a fully updated curve taking into consideration new Holocene treering data, a floating European tree-ring record anchored with quantifiable uncertainty, U/Th-dated

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corals, speleothems, varved sediments, and other marine and terrestrial data sets with climatic correlation to independently dated timescales. To utilize many of the archives requires assumptions about the size and time-dependency of reservoir offsets. Considerable progress has been made in our understanding of these systems which will aid in this process. Progress has also been made modeling the sources of uncertainty and error dependence within the data. The random walk model (rwm) used to construct IntCal04, Marine04, and SHCal04 has been re-implemented using a Markov Chain Monte Carlo algorithm (Blackwell and Buck 2008) to allow greater flexibility. This no longer requires us to treat the value of the calibration curve at adjacent points as independent. Furthermore we are able to incorporate ordering constraints and adaptively estimate the rwm’s variability. Future work will include investigating reservoir offset dependency and permitting more inhomogeneous changes in the calibration curve’s value through time. In the meantime, an interim curve will be provided which includes the absolute tree-ring extension to ca. 12550 cal BP, Cariaco Basin and Iberian margin data sets on the Hulu Cave U/Th timescale, and additional published coral data. Atlantic marine data at the beginning of the Younger Dryas will be omitted for ca. 400 years based on evidence of a decline in the surface reservoir age. The tree-ring based calibration curve to ca. 12,000 cal BP will remain unchanged in the interim curve.

Plenary Session 3: First Detection of Radiocarbon Using AMS: A Retrospective #12 FIRST AMS MEASUREMENTS USING A CYCLOTRON - A REVIEW

Richard Muller Lawrence Berkeley Laboratory, University of California, Berkeley CA 94720, USA.

My journey to AMS began in 1974, when Will Happer suggested the possibility of using lasers to detect minute radioactive trails from a nuclear submarine. Luis Alvarez was familiar with the unsuccessful work by Michael Anbar using a mass spectrometer to attempt direction detection of 14C, and he suggested to me the laser method might work for radiocarbon. I tried hard to make it succeed, and failed, but that’s how I became aware of the potential of direct detection. Later, I became involved in a quark search with Alvarez using a cyclotron. We found no quarks, but I recognized that the high-energy accelerator allowed enormous background suppression and could be used for 14C. The first experimental successes we had with this new method (soon to be called AMS) was with tritium dating; later we were the first to succeed with 10Be. Shortly after our Berkeley team announced the idea and the tritium success, and several other groups immediately recognized the potential advantage of using a tandem van de Graaff, since negative ions suppressed the nitrogen backgrounds. The tandem quickly dominated the field. Eventually, we built a table-top negative ion cyclotron at Berkeley, and managed to make AMS for 14C work on this small device. But the field exploded, and left me way behind, watching in amazement as AMS developed into a standard tool for not only for radioisotope dating, but for applications in medicine and geophysics.

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#13 ANCIENT AMS: DEVELOPMENT OF AMS AT MCMASTER UNIVERSITY

Erle Nelson Simon Fraser University, Burnaby, BC, Canada.

As requested, this talk will be a personal and subjective recounting of the circumstances and the details of the experiment described in Nelson, Korteling, and Stott (1977), Science 198, p 507.

Plenary Session 4: Intercomparisons #14 THE RADIOCARBON INTERCOMPARISON (VIRI): (PART 1) THE FINAL STAGE

P Naysmith1, E M Scott2, G T Cook1 1. SUERC, Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride G75 0QF, Scotland, UK. 2. Statistics Department, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.

The Fifth International Radiocarbon Intercomparison (VIRI) continued the tradition of TIRI (third) and FIRI (fourth) providing an independent check on laboratory procedures. VIRI was designed to have three stages, spread over several years, involving two sets of specific sample types (grain and bone), and then a final stage involving a wide variety of common sample materials. In stage 3, 7 samples were provided to all laboratories, comprising 3 wood samples, as well as cellulose, shell, barley mash and humic acid samples (samples K, L, M, O, R, S, U). Radiometric laboratories received a further charcoal sample (sample P). while a further 4 samples were provided for AMS laboratories, comprising one further wood sample, a charcoal and two humic acid samples (sample N, Q, T, J). More than 50 laboratories, of which 19 were radiometric) participated. In addition, many AMS facilities reported replicate results. In the preliminary analysis, initial consensus values were calculated using the median, which also led to the identification of a number of outlying values. Then, the consensus or assigned values were calculated using a weighted average. For the analysis, for the first time, we have reported z scores, calculated as Z = (XM – XA) / σp where XM, is the reported result, XA is the assigned or true value for the material, and σp is the target value for the standard deviation for values of X. The value for σp is determined by fitness for purpose and represents the amount of uncertainty in the results that is tolerable in relation to the purpose of the analysis, although more commonly the laboratory quoted error is used. XA may be known or assessed as the consensus value. Interpretation of the z score reflects the accuracy achieved and provides a means of making a judgement concerning fitness for purpose. Results from the third stage of VIRI are reported and assigned values given for the 12 samples used.

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#15 THE RADIOCARBON INTERCOMPARISON (VIRI): (PART 2) AN OVERALL ASSESSMENT OF LABORATORY PERFORMANCE

E M Scott1, G T Cook2, P Naysmith2 1. Statistics Department, University of Glasgow, Glasgow G12 8QQ, Scotland, UK. 2. SUERC, Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride G75 0QF, Scotland, UK.

Proficiency testing is a widely used, international procedure common within the analytical chemistry community. A proficiency trial (which VIRI is) often follows a standard protocol, including the analysis which is typically based on z scores, with one key quantity σp. From a laboratory intercomparison (sometimes called a proficiency trial), we hope to gain an assessment of accuracy (in this case from the dendrodated samples), laboratory precision (from the duplicate samples), and generally measurement variability and hence realistic estimates of uncertainty. In addition, given our stated aim of creating an archive of reference materials, we also gain a determination of consensus values for new reference materials. What do laboratories gain from taking part? Firstly, participation helps ensure the results from a laboratory are meaningful; it contributes to and enhances the laboratory’s reputation. What do participating labs want? They want to have relevant test material (samples), confidence in the homogeneity of test material and confidence in the assigned value. VIRI samples have been chosen to deliver these objectives and the sample ages included in the different stages, by design, spanned modern to background. With regard to pretreatment, some samples required intensive pretreatment (e.g. bone), while others required none (e.g. cellulose and humic acid). Sample size was not optimized, and indeed some samples were provided solely for AMS measurement. In this sense, VIRI presented a more challenging exercise than previous intercomparisons, since by its design in stages, one can explore improvements (or deteriorations) over time in laboratory performance. The analysis of the results makes use of the idea of z scores, which are widely used in the general area of proficiency testing and delivers a set of assigned ages for each sample (and their uncertainties). At each stage, more than 50 laboratories have participated, with an increasing demographic shift towards more AMS and fewer radiometric laboratories. In this paper, an overview of the complete exercise will be presented.

#16 AMS SAMPLE COMPARISON CLOSE TO THE LIMIT OF THE METHOD: A LIMIT OR CHALLENGE?

Sahra Talamo and Mike Richards Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany.

Bone is a commonly used material in radiocarbon dating yet, at ages close to the limit of the method, it presents a substantial challenge to remove contamination and produce accurate ages. We report here preliminary results of a dating study of two bones older than 30,000 years each treated with a suite of pretreatment procedures, especially ultrafiltration (Brown et al. 1988). Substantial differ-

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ences in the age determination were observed, which is most likely linked to crucial steps in the removal of contamination both in the bone and in the laboratory. In short, using a comprehensive sequence of pretreatment procedures, including ultrafiltration, we obtain generally older and more consistent ages. Brown TA, Nelson DE, Vogel JS, Southon JR. 1988. Improved collagen extraction by modified Longin method. Radiocarbon 30(2):171–7.

#17 ARE UNIVERSAL COMPACT AMS FACILITIES A COMPETITIVE ALTERNATIVE TO LARGER TANDEM ACCELERATORS?

M Suter, A M Müller, V Alfimov, C Christl, T Schulze-König, H-A Synal, L Wacker Laboratory of Ion Beam Physics, Schafmattstrasse 20, CH-8093 Zürich, Switzerland.

In the last decade, small and compact AMS systems became available which are operated at terminal voltages of 1 MV and below. This new category of instruments has become competitive for radiocarbon detection to larger tandem accelerators and meanwhile many of these instruments are successfully used for radiocarbon dating or biomedical applications. The AMS group in Zurich has also demonstrated that small universal instruments can be built, which allow measurements for many other radioisotopes such as 10Be, 26Al, 129I, and actinides. In addition, sufficient sensitivity is obtained to perform 41Ca measurements for biomedical applications. A summary of the recent developments made at the 600kV Pelletron in Zurich is given and the performance is compared with that of a commercial compact instrument from HVEE operating at 1 MV at CNA in Seville, Spain, as well as with that of larger AMS facilities. It turns out that the ion optics and the detection system are very essential for the performance. The most challenging problem is the measurement of 10Be because of the high intensity of 10B, which has to be suppressed by 8–10 orders of magnitude. A foil degrader method combined with a highresolution gas ionization detector provides the suppression power needed. With a second magnet on the high-energy side, isotopic background (9Be) can be eliminated. An overall transmission of more than 10% for 10Be can be expected. At the same time, this second magnet improves also the mass resolution for heavy isotopes.

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PARALLEL ORAL SESSIONS Parallel Session 2-1: Bone Dating and Chemistry #18 THE CARBON ORIGIN OF STRUCTURAL CARBONATE IN BONE APATITE OF CREMATED BONES

Mark Van Strydonck1, Mathieu Boudin1, Guy De Mulder2 1. Royal Institute for Cultural Heritage, Jubelpark 1, 1000 Brussels, Belgium. 2. Department of Archaeology, Ghent University, Blandijnberg 2, 9000 Ghent, Belgium

The validity of 14C dating of cremated bones has been proven in laboratory intercomparison tests as well as in the dating of duplicate samples of charcoal/cremated bone. Post-depositional contamination of well-cremated bones seems to be limited to the deposition of secondary carbonate and no CO3 radicals are trapped by substitution. Nevertheless, the fact that charred bones showed aberrant results even after proper pretreatment means that the possibility of CO3 substitution must be reconsidered. The most observable chemical changes in the bone, however, do not occur during the post-depositional phase, but during the cremation phases: dehydration, burning of the collagen, changes in crystallinity, and loss of structural carbonate. So if any exchange between the environment and the bone carbonate is happening, it is most probably taking place during the cremation. Because the radiocarbon age of the fuel in a pyre (relatively young trees) is comparable with the age of the cremated body, a possible exchange is not recognizable in the date. In order to circumvent this problem, fresh animal bones were cremated under laboratory conditions designed to emulate as much as possible a normal cremation, but with the use of a fossil fuel. In the first experiment, bone was cremated in an electric furnace filled with coal (anthracite) and in the second experiment bones were cremated in the flame of a bunsen burner using natural gas. The bunsen and the bone were placed in a brick housing to create a protected atmosphere. In both experiments, the CO2 concentration in the ovens was higher than in the free atmosphere and the CO2 was depleted in 14C. Also, the 14C content of the cremated bones was lower (lower pMC) than the 14C content of a bone from the same animal cremated in the electric furnace under natural conditions. Duplicate measurements gave similar results, but important differences in 14C content of the cremated bones in the electric oven with the coal and the cremation in the flame of the bunsen were observed.

#19 DEVELOPMENT OF A NEW ANALYTICAL METHOD FOR RADIOCARBON DATING BONES USING THE AMINO ACID HYDROXYPROLINE

Anat Marom, James S McCullagh, Robert E M Hedges Research Laboratory for Archaeology and the History of Art, University of Oxford, UK.

Bones are widely found in archaeological sites, and have been radiocarbon dated successfully for the past several decades. Isolation and analysis of bone-specific molecules continues to be of interest, however, as a way of eliminating contamination from soil and museum treatment. 4-hydroxyproline (Hyp) serves as an ideal candidate, consisting of about 10% of bone collagen but not found in significant amounts elsewhere in nature.

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A method for the separation and isolation of amino acids from bone collagen has been developed in the Oxford lab, using a mixed-mode (i.e. ion-exchange combined with hydrophobic mechanisms), semipreparative HPLC. The amino acids do not require derivatization, and no organic solvents are used, thereby avoiding addition of carbon. The Hyp fraction can therefore be isolated from hydrolyzed bone reasonably easily, in principle providing reliable dates. We describe the developments necessary to minimize laboratory-derived contamination in sample processing and to optimize the transfer from HPLC output to the graphitization process. We will present data demonstrating the isolation of Hyp does not add significant background carbon to the radiocarbon measurement, together with preliminary dates. In order to verify the accuracy and precision of the technique, we intend to obtain radiocarbon dates on archaeological bone samples which are very old (>45 kyr), highly contaminated, or have too low collagen for normal chemical methods.

#20 RADIOCARBON AGE OF BONE FRACTIONS FROM UNDERWATER-COLLECTED GRAY WHALE BONES, JY REEF, OFFSHORE GEORGIA, USA

Alexander Cherkinsky1, Scott E Noakes1, Ervan G Garrison1, Greg B McFall2 1. The University of Georgia, Athens, GA 30602, USA. 2. The Grays Reef National Marine Sanctuary, NOAA, Savannah, GA 31411, USA.

The gray whale exists now only in the North Pacific Ocean and is completely extinct from the North Atlantic Ocean since the end of the 18th century. To date, there is very a little information about radiocarbon dating of underwater bone samples in the literature. During the last 3 years, scientific divers from UGA and NOAA have been conducting research at JY reef, approximately 20 nautical miles offshore Georgia, USA. JY Reef is an ancient shell bed reef that is slowly eroding due to natural ocean currents and storm events. The shell bed reef is primarily composed of large cold-water scallops and has been dated in the range of 33 to 40 kyr. As a result of the erosion, research divers have recovered four mineralized bones of gray whales in about 17 m of seawater. The samples have been dated on the organic fraction and mineral fraction of bioapatite. The bone shape was very well preserved; however, the collagen fraction was almost completely destroyed and the concentration of organic carbon was below 0.3%. In all four cases, the bioapatite fractions have an older radiocarbon age in the range of 33–37.5 kyr, whereas the organic, collagen-like fractions were significantly younger with radiocarbon ages from 8.3 to 23 kyr. The oldest organic fraction age is in the most dense rib bone, which is also youngest on the bioapatite fraction. The dense bone is less exposed to attacks by microorganisms and apparently still preserved some original collagen, which certainly has been contaminated by products of decomposition. Thus, the Pleistocene bones buried underwater condition could not be dated by the organic fraction due to high microbiological activity, decomposition of original collagen, and replacement of it with foreign organic matter, which is significantly younger than the bone itself.

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#21 DIETARY RECONSTRUCTION AND RESERVOIR CORRECTION OF FROM PAGAN AND EARLY CHRISTIAN GRAVES FROM ICELAND

14C

DATES ON BONES

Árný E Sveinbjörnsdóttir1, Jan Heinemeier2, Jette Arneborg3, Niels Lynnerup4, Gudmundur Ólafsson5, Gudný Zoëga6 1. Institute of Earth Sciences, University of Iceland, Sturlugata 7, IS-101 Reykjavík, Iceland. 2. AMS 14C Dating Centre, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark. 3. The National Museum Of Denmark, Frederiksholms Kanal 12, DK-1220 Copenhagen K, Denmark. 4. Laboratory of Biological Anthropology, Panum Institute, Blegdamsvej 3 DK-2200, Copenhagen N, Denmark. 5. National Museum of Iceland, Sudurgata 41, IS-101 Reykjavík, Iceland. 6. The Skagafjordur Heritage Museum, 560 Varmahlíd, Iceland.

In this study, δ13C and δ15N of bone samples from 60 skeletons (57 humans, 2 horses, and a dog) excavated from pagan and early Christian graves from 20 localities in Iceland are used to reconstruct diet of the first settlers in Iceland and possible differences in diet depending on distance between excavation site and the seashore. We have 14C dated 19 of these skeletons and used the carbon isotopic composition (δ13C) to correct for the marine reservoir effect (the 14C difference between terrestrial and mixed marine organisms). The reservoir-corrected ages lie in the range of 783 ± 36 to 1159 ± 35 BP, or from AD 887 to 1258. The reservoir age corrections were checked by comparing 14C dates of a horse (terrestrial), a dog (highly marine), and a human (mixed diet) from the same burial. The range in measured marine protein percentage in individual diet is from about 10% up to 60%, mostly depending on the geographical position (distance from the sea) of the excavation site. We had access to the skeleton (AAR-5908) of the Skálholt bishop Páll Jónsson, whose remains are enshrined at the Episcopal residence in Skálholt, southern Iceland. According to written sources, the bishop died in AD 1212. According to our dietary reconstruction, his bones were about 17% marine, which is within the range of human skeletons from the same geographical location. The reservoir corrected radiocarbon age of the skeleton agrees with the historical date. We also report measurements of 24 skeletons from the Christian/conversion period cemetery site of Keldudalur, in Skagafjördur, northern Iceland, and some pagan graves close by with bones from humans and a dog, excavated in 2002–3. AMS reservoir-corrected 14C datings of the 24 skeletons confirm that the cemetery dates from just after AD 1000 up to the early 12th century, suggesting that it was in use only for 100–150 years. About 20% of individual diet was from marine resources.

#22 EXPERIMENTAL STUDY ON THE ORIGIN OF CREMATED BONE APATITE CARBON

Matthias Huels, Pieter M Grootes, Marie-Josée Nadeau, Helmut Erlenkeuser, Nils Andersen Leibniz Laboratory for Radiometric Dating and Isotope Research, Christian Albrecht University, Kiel, Germany.

Bones which underwent burning at high temperatures, i.e. cremation, do not contain organic carbon anymore. Lanting et al. (2001) proposed that some of the original structural carbonate, formed during bioapatite formation, survived. Parallel radiocarbon dating of cremated bone apatite and contemporary charcoal presented in their study seems to confirm this assumption. However, stable carbon isotope composition of carbonate in cremated bones is consistently lighter than in uncremated material and is closer to the δ13C values seen in C3 plant material. This raises the question of the origin of carbonate in cremated bone apatite, i.e. is the isotope signal caused by isotopic fractionation

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during cremation or by an exchange of carbon with the local cremation atmosphere and thus carbon from the burning fuel. To study the changes in carbon isotopes (14C, 13C) of bone apatite during burning up to 800 °C a modern bovine bone (14Ccol: 106.2 pMC, δ13Ccol: –13.4‰, δ13Cap: –5.0‰) was exposed to a continuous flow of an artificial atmosphere (basically a high-purity O2/N2 gas mix) under defined conditions (temperature, gas composition). To simulate the influence of the fuel carbon available under real cremation conditions, fossil CO2 (14C: 0.18 ± 0.02 pMC, δ13C: –32.64 ± 0.01‰) was added at different concentration. Infrared vibrational spectra revealed details on the crystal configuration of the burned material. To get cremated bone apatite material similar to archaeological cremated bone apatite, according to crystallographical criteria, it was necessary to add water vapor (ultra pure) to the atmosphere within the oven. The isotope results indicate an effective exchange of carbon between bone apatite and atmosphere depending on temperature and CO2 concentration.

#23 DIETARY HABITS AND FRESHWATER RESERVOIR EFFECTS IN BONES FROM A NEOLITHIC NORTHERN GERMAN CEMETERY

Jesper Olsen1, Jan Heinemeier2, Harald Lübke3, Friedlich Lüth4, Thomas Terberger5 1. Department of Earth Sciences, Aarhus University, Denmark. 2. Department of Physics and Astronomy, Aarhus University, Denmark. 3. Archaeological State Museum, ZBSA, Germany. 4. Römisch-Germanische Kommission Frankfurt, Germany. 5. Chair of Prehistory. University of Greifswald, Germany.

Within a project on Stone Age sites of northeastern Germany, 26 burials from the Ostorf cemetery and some further Neolithic sites have been analyzed by more than 40 AMS dates. Eighteen individuals have also been studied on stable isotopes and will be discussed in this presentation. We here present the results of stable isotope and radiocarbon measurements together with control radiocarbon dates on grave goods from terrestrial animals such as tooth pendants found in 11 of the graves. Age differences between human individuals and their associated pendants are used to calculate 14C reservoir effects. The resulting substantial reservoir effects have lead to misleadingly high radiocarbon ages of their remains, which originally indicated a surprisingly early occurrence of graves and long-term use of this Neolithic burial site. We demonstrate that in order to radiocarbon date the human bones from Ostorf cemetery, it is of utmost importance to distinguish between a terrestrial- versus freshwater-influenced diet. The latter may result in significant reservoir ages with apparent radiocarbon ages up to ca. 800 yrs too old. The carbon and nitrogen isotopic composition may provide a basis for or an indicator of necessary corrections of dates on humans where no datable grave goods of terrestrial origin such as tooth pendants or tusks are available. Based on the associated control animals, there is no evidence that the dated earliest burials occurred any earlier than 3300 BC, in contrast to the original first impression of the grave site.

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Parallel Session 3-1: Radiocarbon & AMS - Small and Large I #24 MICADAS: ROUTINE AND HIGH-PRECISION RADIOCARBON DATING

L Wacker1, G Bonani1, I Hajdas1, B Kromer2, M NÏmec1,3, M Ruff1,3, H-A Synal1 1. Ion Beam Physics, Paul Scherrer Institute and ETH Zurich, 8093 Zurich, Switzerland. 2. Heidelberg Academy of Sciences, 69120 Heidelberg, Germany. 3. Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland.

The MIni CArbon DAting System (MICADAS) is in routine operation at ETH Zurich for more than 1½ years. The instrumental limits and their impact on real measurements were extensively explored during this time and will be presented. A series of measured reference materials and samples with a known age in the range from modern back to 45 kyr BP will demonstrate the reliability and stability. The MICADAS performs extremely well and goes beyond what is generally accepted as high-precision radiocarbon measurements (