bluuebunny/crossref_metadata_2025 huggingface dataset:
The Varying Radiocarbon Activity of Some Recent Submerged Estonian Plants Grown in the Early 1990s
Authors: Olsson Ingrid U , Kaup Enn
Published: July 2016

Eleven samples of aquatic plants from three Estonian lakes were analyzed for their radiocarbon content in a collaboration between the laboratories in Tallinn and Uppsala. δ13C values for the actual species were compiled to allow normalization of activities measured in Tallinn without δ13C values. The range for well determined species is usually a few per mil and the statistical uncertainty ≥1‰. δ13C values vary considerably for differentPotamogétonspecies andMyriophýllumspp. Lake Äntu Sinijärv and Lake Päidre are hard-water lakes containing 300 and 200 mg HCO3–/L, respectively. One sample consisted of a carbonate crust deposited on aCeratophýllum demersumplant in L. Äntu Sinijärv. Its Δ14C value was −147.3 ± 6.7‰ in 1990, whereas the plant had a value of −74.1 ± 8.0‰ (δ13C = −35.0‰). The same species in L. Päidre had a Δ14C value of +8.0 ± 8.8‰ (δ13C = −25.2‰) in 1992. Other species in L. Päidre contained more14C, from a Δ14C value of about +30‰ to about +155‰, the latter value measured in Tallinn on floating leaves ofNuphar lútea,close to that of the contemporaneous atmospheric CO2. In the third lake, Lake Punso, containing ≤30 mg HCO3–/L, the stems ofNuphar lúteaexhibited in 1990 a memory effect: the activity, Δ14C = 209.6 ± 10.3‰, significantly exceeded that of the contemporaneous atmospheric CO2. However, the floating leaves of the same plant had the Δ14C value 143.1 ± 10.0‰, close to the atmospheric14C level in 1990. The memory is explained by nutrients stored in the root stock, used when the growth starts.
Radiocarbon Age Profiles and Size Dependency of Mixing in Northeast Atlantic Sediments
Authors: Brown Louise , Cook Gordon T , MacKenzie Angus B , Thomson John
Published: July 2016

In recent years, the most common technique for radiocarbon dating of deep-ocean sediments has been accelerator mass spectrometry (AMS) analysis of hand-picked planktonic foraminifera (forams). Some studies have exposed age offsets between different sediment size fractions from the same depth within a core and this has important implications when establishing a chronological framework for palaeoceanographic records associated with a particular sediment component. The mechanisms generating the age offsets are not fully understood, a problem compounded by the fact that the fraction defined as “large” varies between different studies. To explore this problem, we dated samples of hand-picked forams from two Biogeochemical Ocean Flux Study (BOFS) cores, for which the presence of an offset between the bulk carbonate and >150 μm foraminiferal calcite had already been demonstrated. The presence of a constant age offset between bulk carbonate and coarse fraction material at the two BOFS sites has been confirmed, but the magnitude of the offset is dependent on whether a simple size-separation technique or hand-picking of well-preserved forams is applied. This may be explained if the selection of well preserved forams biases the sample towards those specimens that have spent least time in the surface mixed layer (SML) or have undergone less size selective mixing. Modeling of the 14C profiles demonstrates that SML depth and sediment accumulation rates are the same for both the bulk and coarse sediment fractions, which is consistent with the hypothesis that size-selective mixing is responsible for the age offset.
The Site of Verrebroek ‘Dok’ and its Contribution to the Absolute Dating of the Mesolithic in the Low Countries
Authors: Van Strydonck Mark J Y , Crombé Philippe , Maes Ann
Published: July 2016

The wetland site of Verrebroek “Dok” situated in northern Belgium is one of the largest and best dated locations of Mesolithic material in northwestern Europe. Salvage excavations organized since 1992 at this large, unstratified open-air settlement have revealed more than 50 spatially independent artifact concentrations with traces of numerous fireplaces. Single entity dating of charred hazelnut shells from surface-hearths and charcoal from hearth-pits was used to obtain information not only on the sites duration, but also on the relation between the surface hearths and the hearth-pits. The dates were also used to look at discrepancies between the radiocarbon chronology and the typo-chronology of the lithic artifacts.
Towards a Radiocarbon Chronology of the Late-Glacial: Sample Selection Strategies
Authors: Walker M J C , Bryant C , Coope G R , Harkness D D , Lowe J J , Scott E M
Published: July 2016

This paper outlines a dating program designed to test the reproducibility of radiocarbon dates on different materials of Late-Glacial age (plant macrofossils, fossil beetle remains, and the “humic” and “humin” chemical fractions of limnic sediments) using a combination of radiometric (beta counting) and accelerator mass spectrometry (AMS) techniques. The results have implications for the design of sampling strategies and for the development of improved dating protocols, both of which are important if a high-precision14C chronology for the Late-Glacial is to be achieved.
The Copper Age in Northern Italy
Authors: Zoppi U , Fulcheri E , Gambari F M , Hua Q , Lawson E M , Micheletti Cremasco M , Gambari M Venturino
Published: July 2016

During the period between the IVth and IIIrd millennia BC, profound changes for the ancient populations inhabiting the northern region of Italy occurred. The first Indo-European migrations were altering the ethnographic characteristics and, with the production of the first copper artifacts, the Neolithic Age was drawing to an end. The most significant testimony of that dramatic period is unquestionably the Ötztal iceman. In addition, many other valuable archaeological sites, such as Alba (Cuneo, Italy), have been discovered. Although Alba produced the oldest evidence of copper objects in a Neolithic context (5380 ± 40 BP; GX-25859-AMS), more recent discoveries have underlined the importance of this archaeological site. In this paper we will report on a series of radiocarbon measurements of bone remnants which, combined with morphologic, stratigraphic, paleoanthropologic, and paleopathologic studies, have allowed us to gain new insights into the culture and chronology of the European Copper Age.
New Chronological Frame for the Young Neolithic Baden Culture in Central Europe (4th Millennium BC)
Authors: Wild Eva Maria , Stadler Peter , Bondár Mária , Draxler Susanne , Friesinger Herwig , Kutschera Walter , Priller Alfred , Rom Werner , Ruttkay Elisabeth , Steier Peter
Published: July 2016

The Baden Culture is a widely spread culture of the Young Neolithics in east-central Europe. In southeast Europe, several parallel cultures are found at different places. The main innovations in east-central Europe associated with the Baden Culture were traditionally thought to originate in southeast Europe, Anatolia, and the Levant. However, in recent years, doubt about this theory has arisen among archaeologists.

Here, we try to contribute to this question by increasing the radiocarbon data set available for the Baden Culture. Thirty-two age determinations of samples from different sites assigned to the Baden Culture were performed by accelerator mass spectrometry (AMS)14C dating. The new data were combined with previously published14C dates. Data from the individual cultural phases of the entire Baden period and the parallel cultures in southeast Europe (Sitagroi, Cernavoda, and Ezero) were analyzed by sum calibration. Comparison of the results indicates that the southeastern cultures cannot be synchronized with the Boleráz period, the early phase of the Baden Culture. It seems that these cultures were parallel to the Baden Classical period. This finding, which has to be verified by more data from the southeastern cultures, contradicts the theory of the east-west spreading of these cultures.
A Chronology of the Scythian Antiquities of Eurasia Based on New Archaeological and 14C Data
Authors: Alekseev A Yu , Bokovenko N A , Boltrik Yu , Chugunov K A , Cook G , Dergachev V A , Kovalyukh N , Possnert G , van der Plicht J , Scott E M , Sementsov A , Skripkin V , Vasiliev S , Zaitseva G
Published: July 2016

The paper is compares the chronology of the monuments of the Scythian epoch located in the east and west of the Eurasian steppe zone on the basis of both archaeological and radiocarbon data. The lists of 14C dates for the monuments located in different parts of Eurasia are presented according to the periods of their existence. Generally, the 14C dates are confirmed the archaeological point of view and allow us to compare the chronological position of the European and Asian Scythian monuments on the united 14C time scale.
Radiocarbon Chronologies of Holocene Lacustrine Sediments from the Southern Coast of Buenos Aires Province, Argentina
Authors: Fontana Sonia L
Published: July 2016

Two lacustrine sediment sequences, La Olla 1 and Laguna del Sauce Grande, on the southern coast of Buenos Aires Province, Argentina, were investigated for carbon reservoir effects, which may influence age-depth chronologies. Fruits of the submerged macrophyte Ruppia cf. maritima from the La Olla 1 sequence, and gastropod shells of Heleobia parchappii from the Laguna del Sauce Grande core, were radiocarbon dated. In addition, terrestrial plant remains and shells of living specimens were dated to assess the presence and magnitude of a reservoir effect. A reservoir age of about 800 14C yr is estimated for the aquatic plant samples of La Olla 1 for the early Holocene. The reservoir effect is attributed to the in wash of 14C-deficient bicarbonate from the surrounding sand dunes. The decay of marine organisms and salt spray are likely the main sources of 14C-deficient carbon. The magnitude of the reservoir effect is consistent with marine reservoir offsets reported for the region. The 14C measurements on shells of living and fossil specimens of Heleobia parchappii indicate the absence of a reservoir effect at Laguna del Sauce Grande, which may be due to the large size and shallow nature of the lake. This study shows how the reservoir ages of 2 close-by lakes in very similar geological settings can be largely different. These results have significant implications for the interpretation of 14C dates from lacustrine deposits in the region.
Evaluation of Possible Contamination Sources in the14C Analysis of Bone Samples by FTIR Spectroscopy
Authors: D'Elia Marisa , Gianfrate Gabriella , Quarta Gianluca , Giotta Livia , Giancane Gabriele , Calcagnile Lucio
Published: July 2016

In the sample preparation laboratory of CEDAD (CEnter for DAting and Diagnostics) of the University of Lecce, a protocol for the quality control of bone samples based on infrared spectroscopy has been set up. The protocol has been recently developed as a check-in test with the aim to identify the presence of collagen in the samples, assess its preservation status, and determine whether the submitted bone samples are suitable for accelerator mass spectrometry (AMS) radiocarbon measurements or not. We discuss in this paper the use of infrared-based techniques to identify the presence of “contaminants” such as restoration and consolidation materials, humic acids, and soil carbonates, which, if not removed by the sample processing chemistry, can be sources of exogenous carbon and can thus influence the accuracy of the14C determinations.

Bone samples recovered in well-defined and previously dated archaeological contexts were intentionally contaminated, submitted to the standard method for collagen extraction and purification, and then characterized by means of Fourier transform infrared (FTIR) spectroscopy analyses performed in attenuated total reflection (ATR) mode before being combusted, converted to graphite, and measured by AMS. The study shows that the ATR-FTIR technique is an extremely powerful method for the identification of both the collagen and its contaminants and can supply important information during the selection and processing of samples to be submitted for14C dating.
Removal of Contaminants from Oracle Bones During Sample Pretreatment
Authors: Yuan Sixun , Wu Xiaohong , Liu Kexin , Guo Zhiyu , Cheng Xiaolin , Pan Yan , Wang Jinxia
Published: July 2016

Animal bones and tortoise shells were used for divination by the Chinese royal family during the Shang Dynasty (∼16th–11th century BC), and the divination results were recorded as inscriptions on oracle bones and shells, which are very valuable cultural remains and record many important events in the Shang Dynasty period. Thus, radiocarbon dating of oracle bones was used to build a precise chronology of the late Shang Dynasty. Due to their original burial conditions and the fact that in subsequent decades the pieces were traded or archived in museums, oracle bones are expected to be contaminated with exogenous materials from the environment and the conservation process. During dating, we found that some samples were contaminated by conservation chemical reagents. The contaminated samples were purified by removing exogenous chemicals with a series of organic solvents, in a method modified from Bruhn et al. (2001). Both whole bone and gelatin samples were processed with this purification method, resulting in satisfactory improvements in dating results.
Applying the Direct Absorption Method and LSC for 14C Concentration Measurement in Aqueous Samples
Authors: Varlam Carmen , Stefanescu Ioan , Varlam Mihai , Popescu Irina , Faurescu Ionut
Published: July 2016

We investigated a simple, reliable radiocarbon measurement procedure for water samples using the direct absorption method for sample preparation, followed by low-level liquid scintillation spectrometry. This process has involved quantitative evaluation of the conversion steps in order to estimate the appropriate working parameters. The 14C activity of dissolved inorganic carbon (DIC) for several types of water (ranging from seawater to groundwater) has been measured, paying attention to the preparation requirements of each type of water. The main advantage of this method is the simplified sample preparation, allowing measurement of a great number of samples in less time. This method was designed for routine analysis of water samples, and it is proposed particularly for use in 14C monitoring programs of CANDU-type reactors.
A Cremated Bone Intercomparison Study
Authors: Naysmith Philip , Scott E Marian , Cook Gordon T , Heinemeier Jan , van der Plicht Johannes , van Strydonck Mark , Ramsey Christopher Bronk , Grootes Pieter M , Freeman Stewart P H T
Published: July 2016

It is now almost 10 yr since radiocarbon dating of cremated bone was first developed using the small carbonate component contained within the hydroxyapatite-based inorganic fraction. Currently, a significant number of 14C laboratories date cremated bone as part of their routine dating service. As a general investigation of cremated bone dating since this initial development, a small, cremated bone intercomparison study took place in 2005, involving 6 laboratories. Six cremated bone samples (including 2 sets of duplicates), with ages spanning approximately 1500–2800 BP, were sent to the laboratories. The results, which showed relatively good agreement amongst the laboratories and between the duplicate samples, are discussed in detail.
A Report on Phase 1 of the 5th International Radiocarbon Intercomparison (VIRI)
Authors: Scott E Marian , Cook Gordon T , Naysmith Philip , Bryant Charlotte , O'Donnell David
Published: July 2016

The Fifth International Radiocarbon Intercomparison (VIRI) continues the tradition of the TIRI (third) and FIRI (fourth) intercomparisons (Scott 2003) and operates as an independent check on laboratory procedures in addition to any within-laboratory procedures for quality assurance. VIRI is a 4-yr project, with the first suite of samples (grain) sent out in September 2004 and the second suite (bone) sent out in December 2005. Further stages will include samples of peat, wood, and shell with a range of ages.

The 4 grain samples included 2 samples (A and C) of barley mash (20 g for radiometric analysis and 2 g for AMS), a grain (barley) byproduct from the manufacture of Glengoyne malt whiskey. The 2 remaining charred grain samples (B and D) were from excavations at Beth Saida and Tel Hadar, respectively (10 g for radiometric analysis and 4 seeds for AMS) and were provided by Elisabetta Boaretto of the Weizmann Institute. Consensus values for samples A and C are 109.2 (standard deviation [1 σ] = 2.73) and 110.6 pMC (1 σ = 2.48), and 2805 (1 σ = 162.7) and 2835 BP (1 σ = 190.8) for samples B and D, respectively. Sample A is a new sample that was collected in 2001, while sample C was used in the FIRI trial as samples G & J (consensus value 110.7 pMC) and was collected in 1998. The expected ages (on archaeological grounds) of samples B and D are 2800 BP and 2850–2900 BP, respectively. The second suite of samples comprises bone, ranging in age from Medieval to “close to background,” and was distributed in December 2005. Samples for both radiometric and AMS laboratories include E: mammoth bone (>5 half-lives); F: horse bone (from Siberia, excavated in 2001); and H, I: whalebone. Finally, sample G (human bone) was only for AMS laboratories. Some of the issues related to using bone in a laboratory intercomparison will be discussed.
Error and Uncertainty in Radiocarbon Measurements
Authors: Scott E Marian , Cook Gordon T , Naysmith Philip
Published: July 2016

All measurement is subject to error, which creates uncertainty. Every time that an analytical radiocarbon measurement is repeated under identical conditions on an identical sample (even if this were possible), a different result is obtained. However, laboratories typically make only 1 measurement on a sample, but they are still able to provide an estimate of the analytical uncertainty that reflects the range of values (or the spread) in results that would have been obtained were the measurement to be repeated many times under identical conditions. For a single measured 14C age, the commonly quoted error is based on counting statistics and is used to determine the uncertainty associated with the 14C age. The quoted error will include components due to other laboratory corrections and is assumed to represent the spread we would see were we able to repeat the measurement many times.

Accuracy and precision in 14C dating are much desired properties. Accuracy of the measurement refers to the deviation (difference) of the measured value from the true value (or sometimes expected or consensus value), while precision refers to the variation (expected or observed) in a series of replicate measurements. Quality assurance and experimental assessment of these properties occupy much laboratory time through measurement of standards (primary and secondary), reference materials, and participation in interlaboratory trials. This paper introduces some of the most important terms commonly used in 14C dating and explains, through some simple examples, their interpretation.
Radiocarbon Dating the “Wilderness of Zin”
Authors: Bruins Hendrik J , van der Plicht Johannes
Published: July 2016

An important archaeological survey was conducted by Leonard Woolley and T E Lawrence in 1914 on behalf of the Palestine Exploration Fund in the Negev and northeastern Sinai deserts—the “Wilderness of Zin.” The region of Ain Kadeis, associated by some scholars in the 19th century with biblical Kadesh-Barnea, received much attention in their survey and discussions. Concerning the vexed question of Kadesh-Barnea, Woolley and Lawrence gave their preference for the nearby Ain el Qudeirat Valley, and in particular the ancient tell. Their survey contributed significantly in the shaping of scholarly opinion on the matter, even until today. But modern surveys and excavations failed to identify any archaeological remnants of the 2nd millennium BCE in the above regions, thereby putting the above associations in question. The Middle Bronze Age II, Late Bronze Age, and Iron Age I that cover this millennium are considered missing in the area in archaeological terms. However, our research reveals that archaeological remains of the 2nd millennium BCE do exist in the region, as determined chronologically by radiocarbon dating. A geoarchaeological approach is required to investigate terraced fields in wadis, which contain a unique record of human activity in these desert regions.
Combined Techniques to Date the First Turkish Bridge Over the Tisza River, Hungary
Authors: Szántó Zsuzsanna , Kertész Róbert , Morgós András , Nagy Dénes , Molnár Mihály , Grabner Michael , Rinyu László , Futó István
Published: July 2016

Given the fluctuating nature of the radiocarbon calibration curve, the precision of single 14C dates on the calendar timescale is limited. However, 14C dating combined with dendrochronology enabled us to date timbers found in the Tisza River, Hungary, during the dry period of summer 2003. Routine preparation of wood samples gave 14C results spread over 4 centuries. By extracting alpha-cellulose from the samples, 2 distinct and relatively narrow historical time periods were obtained: the first period (AD 1505–1595 and 1612–1673, respectively) coincided with the Turkish occupation period, while the second interval (1733–1813) obtained in the case of 2 samples did not exclude the existence of another bridge constructed later. The dendrochronological data confirmed that the bridge was constructed from oak timbers felled between 1558 and 1565. The 14C and dendrochronological dates correspond with the date of a letter written in 1562 by Antal Verancsics, Bishop of Eger, mentioning the construction of the first bridge. In conclusion, the archaeological excavation revealed proof of the first historically attested wooden bridge over the Tisza River.
Chronological Framework of the Siberian Paleolithic: Recent Achievements and Future Directions
Authors: Kuzmin Yaroslav V
Published: July 2016

In Siberia, the accumulation of radiocarbon dates from archaeological sites since the 1960s makes it possible to compile a general Paleolithic 14C database, which contains about 440 entries as of late 2005. With these data, we can reveal the main chronological patterns of Paleolithic complexes, with a focus on the late Middle Paleolithic (Mousterian) and Upper Paleolithic. The 14C dates for late Middle Paleolithic industries in Siberia are quite “young,” up to about 30,000–28,500 BP and perhaps ∼27,000 BP. The emergence of the Upper Paleolithic in Siberia took place relatively early compared with Eastern Europe. At about 43,000–35,000 BP, blade-dominated industries existed in the Altai Mountains and Lake Baikal region, and numerous adornments are known from several sites of that age. The late Upper Paleolithic complexes with microblade technology from the Altai Mountains are 14C dated to about 35,000–28,000 BP, and represent the earliest unequivocal evidence of microblade manufacture in northern Eurasia. The end of the Paleolithic in Siberia is related to the appearance of pottery, which indicates the beginning of the Neolithic period. In northern Transbaikal, the earliest pottery complexes are dated to about 12,000–11,000 BP and in the Russian Far East even to ∼13,000 BP, while in most of Siberia they date to approximately 8000–6000 BP. The most important features of the Siberian Paleolithic chronology are: a) the long persistence of Middle Paleolithic complexes, until about 30,000–27,000 BP; b) very early Middle to Upper Paleolithic transition, ∼43,000 BP, closely connected with the emergence of art and symbolic behavior in the earliest Upper Paleolithic at this time; c) the very early origin of microblade complexes, at least at about 35,000 BP; and d) a gradual Paleolithic–Neolithic transition, beginning in the Russian Far East at ∼13,000 BP and in Transbaikal about 12,000–11,000 BP, in most of Siberia at about 8000–6000 BP, and even later in some northern regions.
Timescale for Climatic Events of Subboreal/Subatlantic Transition Recorded at the Valakupiai Site, Lithuania
Authors: Pawlyta Jacek , Gaigalas Algirdas , Michczyński Adam , Pazdur Anna , Sanko Aleksander
Published: July 2016

Oxbow lake deposits of the Neris River at the Valakupiai site in Vilnius (Lithuania) have been studied by different methods including radiocarbon dating. A timescale was attained for the development of the oxbow lake and climatic events recorded in the sediments. 14C dates obtained for 24 samples cover the range 990–6500 BP (AD 580 to 5600 BC). Medieval human activity was found in the upper part of the sediments. Mollusk fauna found in the basal part of the terrace indicate contact between people living in the Baltic and the Black Sea basins. Mean rates were calculated for erosion of the river and for accumulation during the formation of the first terrace.
Decadal Changes of Bomb Radiocarbon in the Subtropical South Pacific Ocean Between 1992 and 2003
Authors: Kumamoto Yuichiro , Murata Akihiko , Watanabe Shuichi , Fukasawa Masao
Published: July 2016

A basin-scale repeat hydrography of the WOCE-P06 line along approximately 32°S has revealed decadal changes of bomb-produced radiocarbon in the subtropical South Pacific Ocean between 1992 and 2003. Surface δ14C decreased by about 30%. A δ14C decrease was also found in the upper thermocline from the surface to 400 m water depth. In the lower thermocline, from 400 m to 1100 m depth, however, δ14C increased, with a maximum increase of 25% at 700 m depth. This contrast between the upper and lower thermoclines resulted in an overall 10% increase of the specific column inventory of bomb 14C from 1992 to 2003. The global ocean inventory of bomb 14C was assessed based on the specific inventory increase in the subtropical South Pacific Ocean. The meridional distribution of bomb 14C in the early 1990s suggests that the bomb 14C increases observed along 32°S in 2003 were primarily caused by mixing along isopycnals.
Accurate Lacustrine and Wetland Sediment Accumulation Rates Determined from14C Activity of Bulk Sediment Fractions
Authors: Walker W G , Davidson Gregg R , Lange Todd , Wren Daniel
Published: July 2016

In the absence of identifiable macrofossils in lacustrine sediments, radiocarbon dating must rely on pollen or bulk sediment fractions. Bulk sediment fractions are not generally preferred because they contain an unknown mixture of organic material of variable age, they may contain dead carbon such as lignite that is difficult to eliminate, and material of aquatic origin may be subject to reservoir effects. If the various processes that contribute carbon to the system are relatively constant over time, however, changes in14C activity with depth may be used to accurately estimate sediment accumulation rates even if the absolute ages are erroneous. In this study, fine-grained fractions (250–710 μm organic material, humic acids extracted from <250-μm fraction, and untreated <250-μm fraction combusted at low temperature) were analyzed and compared with terrestrial plant stems (twigs), charcoal, and wood fragments in sediments from an oxbow lake in Mississippi, USA. The14C activities of the bulk fractions were highly linear with depth and produced consistent calculated sediment accumulation rates similar to, and perhaps more reliable than, rates determined using twigs or charcoal.
14C Measurements of Tree Rings of a Japanese Cedar During 1945 to 2000 and Core Sampling for Environmental Studies
Authors: Kawamura H , Kofuji H , Gasa S , Kamamoto M , Sawafuji N , Mori M
Published: July 2016

Japanese cedar rings sampled from Aomori Prefecture, Japan, were measured to obtain tree-ring radiocarbon data covering a period of the latter half of the 20th century in the northernmost area of Honshu (mainland Japan), to obtain records of variation in atmospheric 14C concentration caused by past atmospheric nuclear testing, and to study any possible local effects. This work, carried out on a partial disk, was also intended to provide a reference for data obtained by core sampling of live, standing Japanese black pines as a part of marine environmental studies.
Construction of the Calendar Timescale for Lake Wigry (Ne Poland) Sediments on the Basis of Radiocarbon Dating
Authors: Piotrowska N , Hajdas I , Bonani G
Published: July 2016

A radiocarbon chronology of lake sediments deposited in Lake Wigry during the Last Glacial and Holocene periods provided the basis for calendar age-depth modeling. Various fractions (organics and carbonates) were dated and the results were subjected to critical analysis. The dates affected by reservoir effects as well as outlying data were excluded, and the non-linear age model was developed based on 13 ages. The statistical tools used for construction of the models include the Bayesian analysis, applied for calibration of14C dates with regard to stratigraphical position of the samples, and generalized additive models (GAM).
Recurrence and Extent of Great Earthquakes in Southern Alaska During the Late Holocene from an Analysis of the Radiocarbon Record of Land-Level Change and Village Abandonment
Authors: Hutchinson Ian , Crowell Aron L
Published: July 2016

The incidence of plate-boundary earthquakes across 3 prospective tectonic segments at the Alaska subduction zone (ASZ) in the late Holocene is reconstructed from geological evidence of abrupt land-level change and archaeological evidence of discontinuities in occupation of native villages. Bracketing radiocarbon ages on uplifted and down-dropped coastal deposits indicate that great earthquakes likely ruptured the plate interface in the eastern segment (Prince William Sound [PWS]) about 800, 1400, 2200–2300, 2600–2700, 3100–3200, and 3600–3700 cal BP. Evidence for an event about 1900 yr ago, and the possibility that the 2600–2700 cal BP event was a closely spaced series of 3 earthquakes, is restricted to parts of Cook Inlet. Geological evidence from the central (Kenai [KEN]) segment is fragmentary, but indicates that this segment likely ruptured about 1400 yr ago and in the triple event about 2600–2700 yr ago. The geological record from the Kodiak-Katmai (KOKA) segment at the western end of the ASZ has limited time-depth, with localized evidence for ruptures about 500, 1000, and 1300 yr ago.14C ages and stratigraphic descriptions from 82 prehistoric villages and camps on the coast of the Gulf of Alaska reveal fluctuations in site activity that correlate with paleoseismic episodes. Hiatuses in site occupation occurred about 800, 1400, and 2200 yr ago in the PWS and KEN segments. The fragmentary older record from the KEN segment also reveals a hiatus about 2700 yr ago. The 2200–2300 and 2600–2700 cal BP events are also recorded in the KOKA segment, and the great earthquake at about 3200 cal BP may also be recorded there. This suggests that, although the PWS and KEN segments behave as a coherent unit of the Alaska megathrust, the KOKA segment is characterized by semi-independent behavior. At least 2, and perhaps as many as 4, of the last 7 prehistoric great earthquakes at this plate boundary did not propagate this far west.
14C Dating of the Upper Paleolithic Site at Krems-Hundssteig in Lower Austria
Authors: Wild E M , Neugebauer-Maresch C , Einwögerer T , Stadler P , Steier P , Brock F
Published: July 2016

The open-air archaeological site at Krems-Hundssteig is a well-known Upper Paleolithic site located in Lower Austria. The site was discovered in the late 19th/early 20th centuries when a large number of archaeological remains were collected during the course of loess quarrying. Although no systematic excavation has ever been performed, Krems-Hundssteig has been described since its discovery as typical of the Aurignacian period in this region based on the numerous archaeological finds; accordingly, the culture has been namedKremsienby some authors. Surprisingly, the artifacts found in a recent excavation adjacent to this location showed solely Gravettian features, calling into question the original assignment to the Aurignacian. Although the earlier assignment was supported by a radiocarbon date of ∼35 kyr BP (Hahn 1977), new accelerator mass spectrometry (AMS)14C dates proved that the recently excavated cultural layer originates from the Gravettian period. Older paleosols were also detected by sondage drillings at some depth below it.

The new results indicate that a large Aurignacian level and a substantial complex of Gravettian layers are present in this area. Therefore, it must be assumed that more than 1 cultural level was affected and destroyed by the historic loess quarrying, and that the assemblage of Krems-Hundssteig artifacts, traditionally ascribed to the Aurignacian, might be interspersed with Gravettian pieces.
Development of Sample Pretreatment of Silk for Radiocarbon Dating
Authors: Kim Kyeong Ja , Southon John , Imamura Mineo , Sparks Rodger
Published: July 2016

We have developed sample pretreatments for silk for radiocarbon dating. Characteristics of silk under different types of pretreatment were investigated, as well as the behavior of dye and possible contaminants. We found that dye could be removed completely, together with all other foreign materials bigger than 1.2 μm, using a glass microfiber filter after decomposition with 6N HCl. The decomposed proteins were concentrated using Centriprep® ultrafiltration concentrators with 3 different molecular weight cut-offs. By taking a molecular weight fraction—which selects for secondary structures of silk protein—14C dating of silk samples can be made more reliable. This study confirms that uniformly fractured polypeptide chains of silk provide an appropriate fraction for 14C age dating to select silk protein against dye particles and undecomposed foreign contaminants.
Evaluation and Status of Liquid Scintillation Counting for Radiocarbon Dating
Authors: Polach Henry A
Published: July 2016

An international review of liquid scintillation low-level counting procedures and instrumentation made it possible to assess in detail those elements which lead to high-precision liquid scintillation radiocarbon dating with a Figure of Merit of 32,000. Current research is documented and future possibilities are alluded to.
Comparative Study of the Radiocarbon Dating of Different Bone Collagen Preparations
Authors: Gurfinkel D M
Published: July 2016

Four different bone collagen preparation procedures were compared and were found useful as a means of assessing the nature of contaminants present in a sample. Weathered bone however appeared to contain contaminants that could not be eliminated by any of the procedures studied.
14C Background Levels in An Accelerator Mass Spectrometry System
Authors: Vogel J S , Nelson D E , Southon J R
Published: July 2016

The levels and sources of the measurement background in an AMS 14C dating system have been studied in detail. The relative contributions to the total background from combustion, graphitization, storage, handling, and from the accelerator were determined by measuring the C concentrations in samples of anthracite coal ranging in size from 15μg to 20mg. The results show that, for the present system, the uncertainty in the background is greater than that due to measurement precision alone for very old or for very small samples. While samples containing 100μg of carbon can yield useful 14C dates throughout the Holocene, 200 to 500μg are required for dating late Pleistocene materials. With the identification of the procedures that introduce contamination, the level and uncertainty of the total system background should both be reducible to the point that 100μg of carbon would be sufficient for dating most materials.
Determination of Radon by Liquid Scintillation α/β Particle Spectrometry: Towards the Resolution of a 14C Dating Problem
Authors: Polach Henry , Kaihola Lauri
Published: July 2016

Traces of uranium and radium within the 14C sample generate radon (Rn) which gets occluded during the benzene synthesis, thus generating false (extra) counts within the 14C counting window. This, if undetected, gives rise to erroneous 14C age determinations. The application of simultaneous α and β liquid scintillation spectrometry will enable a mathematical evaluation of the 14C signal unaffected by α and β particle emissions from radon decay daughters.
University of Texas at Austin Radiocarbon Dates XVI
Authors: Valastro S , Davis E Mott , Varela Alejandra G , Lisk Susan V
Published: July 2016

This list continues our program to put into print our large backlog of unpublished dates. Those listed here are not a specific block of dates but simply those ready for publication.
Timothy W Linick October 29, 1946–June 4, 1989
Authors: Jull Ajt , Suess Hans E
Published: July 2016

Timothy Weiler Linick died on June 4th, 1989. He was a dedicated researcher, and an important part of the NSF Accelerator Facility for Radioisotope Analysis at the University of Arizona. He will be remembered for his care and attention to details, especially in the calculation and reporting of radiocarbon dates. He made important contributions to the fields of oceanography and tree-ring calibration of the 14C time scale.
Chronometric Dating and Late Holocene Prehistory in the Hawaiian Islands: A Critical Review of Radiocarbon Dates from Moloka'I Island
Authors: Weisler Marshall
Published: July 2016

The importance of chronometric dating in archaeology cannot be overemphasized. Indeed, most chronologies developed throughout the world during the past three decades have depended on radiocarbon age determinations to provide a temporal framework for examining change over time in cultural sequences during the late Pleistocene and Holocene. With the advent of legislation in the mid-1960s designed to protect archaeological sites in the United States threatened by increased urban development or government sponsored projects, archaeological surveys and excavations were mandated as a means for preserving information otherwise destroyed. As a result, thousands of projects have contributed to a growing body of “gray literature,”ie, unpublished proprietary or manuscript reports with very limited circulation. Within these reports are hundreds, if not thousands, of14C age determinations, most of which are not accessible in published form. One objective of this paper is to present all the14C age determinations for the island of Moloka'i, Hawai'i as of December 1988, including 41 dates never before published with stratigraphic details.
Accuracy and Precision in Dating Microgram Carbon Samples
Authors: Vogel J S , Nelson D E , Southon J R
Published: July 2016

The accuracy of AMS radiocarbon determinations on very small samples has been tested by measuring a suite of microgram-sized samples of a known-age material. The total measurement precision for the smallest sample (50μg) was found to be ± 3% and the precision improved with larger sample size. The accuracies of the measurements were found to be within the measurement precisions.
The 4000-Year-Old “Longshan Giant” Discovered in Shaanxi Province, China
Authors: Yang Yachang , Zhu Yizhi
Published: July 2016

A human skeleton of phenomenal size was uncovered during the excavation of a prehistoric site located in the city of Shangnan, Shaanxi province, China, in 2006. The skeleton dates to 4240–4100 cal yr BP, corresponding to the Longshan culture (4400–4000 yr ago). The skeletal characteristics point to a young male 16–18 yr old with a height of 193 cm. This is the tallest skeleton ever discovered in prehistoric China, and thus we name him the “Longshan Giant.” The giant appears to be of the Mongoloid race and has many physical characteristics that are similar to those of modern southern Asians. Upon closer examination, 3 drilled holes of 5 cm in diameter were found in the right parietal bone of the skull. No rationale exists yet to explain the presence of these holes.
The Phytolith14C Puzzle: A Tale of Background Determinations and Accuracy Tests
Authors: Santos Guaciara M , Alexandre Anne , Coe Heloisa H G , Reyerson Paul E , Southon John R , De Carvalho Cacilda N
Published: July 2016

Over the past decades, analysis of occluded carbon in phytoliths (opaline silica mineral bodies that form in and between plant cells) has become a workhorse of paleoclimate and archaeological studies. Since different plant types exhibit distinctive phytolith morphologies, their assemblages are used in identifying vegetation histories or food culture adaptations. A few direct radiocarbon AMS measurements of phytoliths have been carried out, but these measurements are difficult due to the low concentrations of phytoliths in some plant species, and the small amount of C per phytolith (<2%). In addition, no phytoliths samples of a known14C age are available to verify measurement accuracy and precision, and to check sample preparation protocols. Background corrections are also difficult to address due to the lack of suitable material. In this work, we designed a procedure to quantify a suitable blank using SiO2powder samples (close to the opal structure, and free of14C). The full phytolith extraction showed high carbon contamination components: a) ∼3 μg of modern C and ∼2 μg of dead C. We also performed accuracy tests on large phytolith-occluded carbon samples extracted from soils and harvested plants. The unexpected14C ages in some of the results triggered further investigations of possible sources of carbon contamination.
Radiocarbon AMS Data Analysis: From Measured Isotopic Ratios to 14C Concentrations
Authors: Zoppi Ugo
Published: July 2016

Radiocarbon accelerator mass spectrometry (AMS) measurements are always carried out relative to internationally accepted standards with known 14C activities. The determination of accurate 14C concentrations relies on the fact that standards and unknown samples must be measured under the same conditions. When this is not the case, data reduction is either performed by splitting the collected data set into subsets with consistent measurement conditions or by applying correction factors.

This paper introduces a mathematical framework that exploits the intrinsic variability of an AMS system by combining arbitrary measurement parameters into a normalization function. This novel approach allows the en-masse reduction of large data sets by providing individual normalization factors for each data point. Both general features and practicalities necessary for its efficient application are discussed.
AMS Radiocarbon Dates from Pleistocene and Holocene Mammals Housed in the New York State Museum, Albany, New York, USA
Authors: Feranec Robert S , Kozlowski Andrew L
Published: July 2016

Despite its rich paleontological record, only limited research has been published on the Pleistocene and Holocene vertebrate faunal record of New York State. This paper presents a set of dates from the bone collagen of Pleistocene and Holocene mammal specimens housed in the Vertebrate Paleontology Collections at the New York State Museum, Albany, New York, USA.
Personal Recollections of a Good Experiment
Authors: Nelson Erle
Published: July 2016

This is the written version of a retrospective talk given at the 20th Radiocarbon Conference in Hawaii, 2009. As requested, this is not a scholarly work, but simply a personal, subjective account of how a good experiment in the field of radiocarbon dating came about. It differs from the talk itself only in that I have eliminated some sideline commentary so that I can add a few thoughts originally intended for the end, when I had talked myself out of time.
The Low-Energy Isobar Separator for Anions: Progress Report
Authors: Kieser W E , Eliades John , Litherland A E , Zhao Xiaolei , Cousins Lisa , Ye S J
Published: July 2016

The suppression of interferences from atomic and molecular isobars is a key requirement for the extension of accelerator mass spectrometry (AMS) to the analysis of new cosmogenic isotopes and for increasing the range of applications for small AMS systems. In earlier work, it was shown that unwanted isobars can be eliminated by anion-gas reactions (Litherland et al. 2007). Recently, a prototype system in which such reactions could be applied to ions from an AMS ion source, the Isobar Separator for Anions (ISA), was described (Eliades et al. 2009). This system decelerates the beam of rare anions from keV to eV energies, guides them through a single radiofrequency quadrupole (RFQ) gas cell, and re-accelerates them for further analysis in a 2.5MV AMS system. Tests of this system with Cl and S anions and NO2 gas showed a suppression of S with respect to Cl of over 6 orders of magnitude, with a transmission of ∼30% for the Cl beam. In this work, results of the analysis of a range of standard reference materials are reported; these show the linearity of the system for measuring the 36Cl/35Cl ratio over a span of 2 orders of magnitude. Further tests, using the AMS system as a diagnostic tool, have provided clues about the loss of Cl at higher cell pressure and the nature of the residual low level of S transmission. These lead to the assessment of various gases for cooling the Cl– beam. Suppression measurements for 41K in the analysis of 41Ca, using NO2 as a reaction gas, are also discussed. These preliminary measurements have provided data for the development of a more advanced system with separate cooling and reaction cells.
A Beam Profile Monitor for Rare Isotopes in Accelerator Mass Spectrometry: Preliminary Measurements
Authors: Taccetti F , Carraresi L , Fedi M E , Manetti M , Mariani P , Tobia G , Mandò P A
Published: July 2016

In accelerator systems, beam lines are generally equipped with diagnostic elements, such as Faraday cups and beam profile monitors (BPM), to optimize beam transport. These diagnostic elements, or at least commercial ones, are designed to only work with continuous beams, and their typical maximum sensitivity is about few tens of pA. Thus, in the case of diagnosis of rare isotope beams in accelerator mass spectrometry (AMS), Faraday cups and BPMs are not suitable on the high-energy side of the tandem accelerator, after energy-mass-charge analysis. For example, in 14C AMS, even for a modern sample, the expected counting rate is a few tens of Hz; in these conditions, a commercial BPM cannot be used. On the other hand, checking the shape and the position of the rare isotope beam hitting the detector can be important in order to better identify signals in the detector itself, thus also helping in reducing the measurement background.

This paper presents a prototype BPM especially designed for low-intensity beams. The BPM is based on a multiwire proportional chamber characterized by 2 grids of anode wires, oriented perpendicular to each other in order to measure both the x and the y coordinates of the particle impact point. Details about the design and the electronics of the device are given, and the first test measurements are discussed.
Optimization of 236U AMS at CIRCE
Authors: De Cesare M , Guan Y , Quinto F , Sabbarese C , De Cesare N , D'Onofrio A , Gialanella L , Petraglia A , Roca V , Terrasi F
Published: July 2016

Actinide isotopes are present in environmental samples at ultra-trace levels (236U concentration is quoted to be on the order of pg/kg or fg/kg). Their detection requires the resolution of mass spectrometry (MS) techniques, but only accelerator mass spectrometry (AMS) has the sensitivity required. In order to perform the isotopic ratio measurements of actinides, such as 236U/238U, an upgrade of the Center for Isotopic Research on Cultural and Environmental Heritage accelerator (CIRCE) in Caserta, Italy, has been performed. The system was originally equipped for radiocarbon AMS measurements. The main difficulty of AMS measurement of 236U is the intense neighboring beam of 238U. Although most of the 238U ions are suppressed by means of magnetic and electrostatic elements, a small fraction of this intense beam can interfere with the rare isotopes. This paper reports the preliminary results of the 236U/238U isotopic ratio measurement limit (<5.6 x 10–11), aimed also to better understand the origin of background ions. For this purpose, a large 16-strip silicon detector providing spatial resolution has been used. In addition, calculations to assess the performance of the system obtained by adding a high-resolution time of flight-energy (TOF-E) detector are discussed.