Showing papers in "Radiocarbon in 2015"

Vegetation and Climate Changes during the Bronze and Iron Ages (~3600–600 BCE) in the Southern Levant Based on Palynological Records

Abstract: This article presents the role of climate fluctuations in shaping southern Levantine human history from 3600 to 600 BCE (the Bronze and Iron Ages) as evidenced in palynological studies. This time interval is critical in the history of the region; it includes two phases of rise and decline of urban life, organization of the first territorial kingdoms, and domination of the area by great Ancient Near Eastern empires. The study is based on a comparison of several fossil pollen records that span a north-south transect of 220 km along the southern Levant: Birkat Ram in the northern Golan Heights, Sea of Galilee, and Ein Feshkha and Ze’elim Gully both on the western shore of the Dead Sea. The vegetation history and its climatic implications are as follows: during the Early Bronze Age I (~3600–3000 BCE) climate conditions were wet; a minor reduction in humidity was documented during the Early Bronze Age II–III (~3000–2500 BCE). The Intermediate Bronze Age (~2500–1950 BCE) was characterized by moderate climate conditions, however, since ~2000 BCE and during the Middle Bronze Age I (~1950–1750 BCE) drier climate conditions were prevalent, while the Middle Bronze Age II–III (~1750–1550 BCE) was comparably wet. Humid conditions continued in the early phases of the Late Bronze Age, while towards the end of the period and down to ~1100 BCE the area features the driest climate conditions in the timespan reported here; this observation is based on the dramatic decrease in arboreal vegetation. During the period of ~1100–750 BCE, which covers most of the Iron Age I (~1150–950 BCE) and the Iron Age IIA (~950–780 BCE), an increase in Mediterranean trees was documented, representing wetter climate conditions, which followed the severe dry phase of the end of the Late Bronze Age. The decrease in arboreal percentages, which characterize the Iron Age IIB (~780–680 BCE) and Iron Age IIC (~680–586 BCE), could have been caused by anthropogenic activity and/or might have derived from slightly drier climate conditions. Variations in the distribution of cultivated olive trees along the different periods resulted from human preference and/or changes in the available moisture. DOI: 10.2458/azu_rc.57.18555

The Transition from Bronze to Iron in Canaan: Chronology, Technology, and Context

Abstract: In the framework of the European Research Council–funded project, “Reconstructing Ancient (Biblical) Israel: The Exact and Life Sciences Perspective,” we carried out multiple analyses on iron and bronze objects from provenanced contexts in Israel, as well as on previously unidentified metallurgical remains from the production of both metals In addition, we counted anew iron and bronze objects from well-stratified contexts and studied metalworking sequences at major sites, which included those that had undergone the bronze/iron transition This enabled us to clarify some of the issues related to the bronze/iron transition in the southern Levant Using this evidence, we showed that iron was not used for utilitarian purposes before the Iron I (late 12th century BCE) and that iron only became dominant concurrently with the beginning of its systematic production during the Iron IIA (10th–9th centuries BCE) A strong correlation between iron and bronze production suggests that during the Iron I local independent bronzesmiths adopted the new iron technology Under local administrations that developed during the Iron IIA, workshops that previously produced bronze turned to iron production, although they continued to manufacture bronze items as a secondary venture Significantly, at some of the major urban centers iron production was an independent industry that included the entire operational sequence, including the on-site smelting of the ore This development appears to have been a major contributor to the transition to systematic production of iron DOI: 102458/azu_rc5718563

Planktic and Benthic 14C Reservoir Ages for Three Ocean Basins, Calibrated by a Suite of 14C Plateaus in the Glacial-to-Deglacial Suigetsu Atmospheric 14C Record

Abstract: This article presents a compilation of planktic and benthic 14 C reservoir ages for the Last Glacial Maximum (LGM) and early deglacial from 11 key sites of global ocean circulation in the Atlantic and Indo-Pacific Ocean. The ages were obtained by 14 C plateau tuning, a robust technique to derive both an absolute chronology for marine sediment records and a high-resolution record of changing reservoir/ventilation ages (Δ 14 C values) for surface and deep waters by comparing the suite of planktic 14 C plateaus of a sediment record with that of the atmospheric 14 C record. Results published thus far have used as atmospheric 14 C reference U/Th-dated corals, the Cariaco planktic record, and speleothems. We have now used the varve-counted atmospheric 14 C record of Lake Suigetsu terrestrial macrofossils to recalibrate the boundary ages and reservoir ages of the seven published records directly to an atmospheric 14 C record. In addition, the results for four new cores and further planktic results for four published records are given. Main conclusions from the new compilation are the following: (1) The Suigetsu atmospheric 14 C record on its varve-counted timescale reflects all 14 C plateaus, their internal structures, and relative length previously identified, but implies a rise in the average 14 C plateau age by 200–700 14 C yr during the LGM and early deglacial times. (2) Based on different 14 C ages of coeval atmospheric and planktic 14 C plateaus, marine surface water Δ 14 C may have temporarily dropped to an equivalent of ~0 yr in low-latitude lagoon waters, but reached >2500 14 C yr both in stratified subpolar waters and in upwelled waters such as in the South China Sea. These values differ significantly from a widely assumed constant global planktic Δ 14 C value of 400 yr. (3) Suites of deglacial planktic Δ 14 C values are closely reproducible in 14 C records measured at neighboring core sites. (4) Apparent deep-water 14 C ventilation ages (equivalents of benthic Δ 14 C), deduced from the sum of planktic Δ 14 C and coeval benthic-planktic 14 C differences, vary from 500 up to >5000 yr in LGM and deglacial ocean basins. DOI: 10.2458/azu_rc.57.17916

Matching Dendrochronological Dates with the Southern Hemisphere 14C Bomb Curve to Confirm Annual Tree Rings in Pseudolmedia rigida from Bolivia

Abstract: This study used high-precision radiocarbon bomb-pulse dating of selected wood rings to provide an independent validation of the tree growth periodicity of Pseudolmedia rigida (Klotzsch & H. Karst.) Cuatrec. from the Moraceae family, collected in the Madidi National Park in Bolivia. 14 C content was measured by accelerator mass spectrometry (AMS) in 10 samples from a single tree covering over 70 yr from 1939 to 2011. These preliminary calendar dates were determined by dendrochronological techniques and were also used to select the samples for 14 C AMS. In order to validate these preliminary dates using the established Southern Hemisphere (SH) 14 C atmospheric concentration data set, the targeted rings were selected to be formed during periods before and after the 14 C bomb spike nuclear tests (i.e. 1950s–1960s). The excellent agreement of the dendrochronological dates and the 14 C signatures in tree rings associated with the same dates provided by the bomb-pulse 14 C atmospheric values for the SH (SHCal zone 1–2) confirms the annual periodicity of the observed growth layers, and thus the high potential of this species for tree-ring analysis. The lack of discrepancies between both data sets also suggests that there are no significant latitudinal differences between the 14 C SHCal zone 1–2 curve and the 14 C values obtained from the selected tree rings at this geographic location (14°33′S, 68°49′W) in South America. The annual resolution of P. rigida tree rings opens the possibility of broader applications of dendrochronological analysis for ecological and paleoclimatic studies in the Bolivian tropics, as well as the possibility of using wood samples from some tree species from this region to improve the quality of the bomb-pulse 14 C SHCal curve at this latitude. DOI: 10.2458/azu_rc.57.18192

Dead Sea Levels during the Bronze and Iron Ages

Abstract: The history of lake-level changes at the Dead Sea during the Holocene was determined mainly by radiocarbon dating of terrestrial organic debris. This article reviews the various studies that have been devoted over the past 2 decades to defining the Dead Sea levels during the Bronze and Iron Ages (~5.5 to 2.5 ka cal BP) and adds new data and interpretation. In particular, we focus on research efforts devoted to refining the chronology of the sedimentary sequence in the Ze’elim Gully, a key site of paleoclimate investigation in the European Research Council project titled Reconstructing Ancient Israel. The Bronze and Iron Ages are characterized by significant changes in human culture, reflected in archaeological records in which sharp settlement oscillations over relatively short periods of time are evident. During the Early Bronze, Intermediate Bronze, Middle Bronze, and Late Bronze Ages, the Dead Sea saw significant level fluctuations, reaching in the Middle Bronze an elevation of ~370 m below mean sea level (bmsl), and declining in the Late Bronze to below 414 m bmsl. At the end of the Late Bronze Age and upon the transition to the Iron Age, the lake recovered slightly and rose to ~408 m bmsl. This recovery reflected the resumption of freshwater activity in the Judean Hills, which was likely accompanied by more favorable hydrological-environmental conditions that seem to have facilitated the wave of Iron Age settlement in the region. DOI: 10.2458/azu_rc.57.18560

Aquatic Resources in Foodcrusts: Identification and Implication

Abstract: Foodcrusts, the charred surface deposits on pottery vessel surfaces, provide a rich source of data regarding container function. This article reviews recent applications focusing on the detection of aquatic resources (marine and freshwater) in pottery vessels using a range of analytical approaches including bulk isotope measurements of carbon and nitrogen, lipid biomarker analysis, and compound-specific carbon isotope determinations. Such data can help to evaluate the presence of reservoir effects when undertaking radiocarbon dating of foodcrust samples. In particular, molecular and isotopic analysis can aid in the selection of suitable candidates for 14 C where it can be demonstrated that aquatic resources are unlikely to contribute to the residue. Prospects for compound-specific 14 C analysis of lipids in foodcrusts and ceramic-absorbed residues are also discussed. DOI: 10.2458/azu_rc.57.18454

Absolute Dating of the Late Bronze to Iron Age Transition and the Appearance of Philistine Culture in Qubur el-Walaydah, Southern Levant

Abstract: The Late Bronze Age to the Iron Age transition involves profound cultural and political changes in the southern Levant. The transition is dated to the 12th century BC, based on archaeological artifacts and historical documents. A more precise absolute date for this transition for the southern Levant based on radiocarbon is difficult since the 14 C calibration curve reduces precision significantly due to wiggles that form an approximately 200-yr-long plateau. This article analyzes 14 C samples from the Late Bronze Age to the Iron Age transition at Qubur el-Walaydah. To increase the resolution of 14 C dates within the plateau, 14 C samples were collected only from well-defined multilayered contexts. 14 C dates from 11 contexts were obtained and these were analyzed using a Bayesian model that incorporated the stratigraphic information. Using this integrative approach we date the Late Bronze Age III levels at Qubur el-Walydah, containing the initial phase of locally produced Philistine pottery between 1185–1140 BC, and the Late Bronze to Iron Age transition between 1140–1095 BC. DOI: 10.2458/azu_rc.57.16961

New AMS 14C Dates for Human Remains from Stone Age Sites in the Iron Gates Reach of the Danube, Southeast Europe

Abstract: Archaeological investigations in the Iron Gates reach of the Lower Danube Valley between 1964 and 1984 revealed an important concentration of Stone Age sites, which together provide the most detailed record of Mesolithic and Early Neolithic settlement from any area of southeastern Europe. Over 425 human burials were excavated from 15 sites. Of these, less than one-fifth have been directly dated. This article presents 37 new AMS dates on human bone from five sites in the Iron Gates, together with the corresponding δ 13 C and δ 15 N values. They include the first dates on human bone from two sites, Icoana and Velesnica. The results are important for the chronology of Stone Age mortuary practices in the Iron Gates and the timing of the Mesolithic-Neolithic transition in the region.

Highly variable freshwater reservoir offsets found along the upper lena watershed, cis-baikal, southeast siberia

Abstract: A program of paired dating of human and faunal remains on a sample of 11 prehistoric (Mesolithic/Neolithic to Early Bronze Age) graves in the Upper Lena basin, southeast Siberia, was initiated to investigate the freshwater reservoir effect (FRE). The results show the presence of a substantial but highly variable offset, ranging from 255 to 1010 14 C yr. In contrast to previous studies centered on Lake Baikal and the Angara River, human stable nitrogen isotope values show little or no correlation with the radiocarbon offset, despite the clear trophic differences seen in δ 15 N between terrestrial and aquatic sources of protein in the region’s isotope ecology. However, stable carbon isotope measurements show a moderate negative correlation of some predictive value ( r = –0.70, p = 0.016, df = 10). Two different regression equations have been calculated, the first using human δ 13 C values for the entire data set ( r 2 = 0.49) and the second, using both δ 13 C and δ 15 N values, limited to the Early Bronze Age of the southern Upper Lena ( r 2 = 0.84, p = 0.030, df = 5). The source of the old carbon in the Upper Lena River system is not clear. While the river flows over carbonate bedrock and is moderately alkaline, we suggest that old terrestrial carbon entering the riverine foodweb through bank erosion and other processes is a more likely candidate for the majority of the 14 C offset. DOI: 10.2458/azu_rc.57.18458

On the Beginnings of South Asian Spice Trade with the Mediterranean Region: A Review

Abstract: When did the trade in lucrative spices from South Asia to the West commence? Recent organic residue anal- yses performed on small early Iron Age (11th-late 10th century BCE) Phoenician clay flasks provide the first concrete archaeological evidence that such sustainable trade took place much earlier than hitherto suspected. The analysis shows that several of the flasks contained cinnamon, which in this period could only have originated in South/Southeast Asia. Here, we first summarize the rationale and results of that study. Subsequently, we provide an updated review of all sources of data relevant to the question at hand—archaeological, analytical, and textual. Finally, we offer suggestions for future research on the Asian spice trade with the West. INTRODUCTION: SOUTH ASIAN SPICE TRADE WITH THE WEST South/Southeast Asian spices have fired the imaginations of European historians, poets, and trav - elers, and whetted the appetites of elites and rulers ever since the "West" became aware of their existence (Keay 2006). Starting in the 16th century, the quest to dominate the spice trade became a major factor in European colonialism, the development of maritime technologies, and more, and dictated the fate of many of the spice-producing regions and societies (e.g. Corn 1998). But when did the spice trade begin? Based on Greek literary evidence, discussions of the South Asian (mostly Indian) spice trade to the West usually begin with the late 6th/5th centuries BCE, when European acquaintance with cinna- mon and cassia was recorded by Herodotus (3.107-111; 5th century BCE) and by his more-or-less contemporary Melannipides of Melos (Athenaus 14.561F; e.g. Barnstone 2010:157). 1 Herodotusʼ fanciful account (3.107-111) demonstrates that even in this period Europeans had only a vague idea regarding the origin of these spices; cassia and cinnamon were said to be procured by the Arabs (alongside myrrh and frankincense). On the other hand, Herodotus proclaimed that the origin of cinnamon is in fact unknown and that it was brought from Nysa "where Dionysus was reared." For him, this probably meant Ethiopia (2. 146). 2 Per Herodotus (2.86), cassia was used by the Egyptians, alongside myrrh, for embalming. 3 The association of cinnamon/cassia with Arabia suggested by Herodotus (and later writers), and their affiliation with Trogodytica or Somalia in East Africa by Pliny the Elder ( NH XII, 42.19; 1st century CE) led some scholars to suggest that these terms, rather than referring to South Asian spic- es, denote African or Arabian plants, yet unidentified botanically (esp. De Romanis 1996; Crone

Aquatic radiocarbon reservoir offsets in the southeastern baltic

Abstract: The aim of this article is to discuss radiocarbon dating offsets due to freshwater and marine reservoir effects (FRE and MRE, respectively) in the southeastern Baltic. Thirty-six 14 C dates from Lithuanian coastal and inland Subneolithic, Neolithic, and Bronze Age sites as well as two Mesolithic-Neolithic cemeteries are presented here. Accelerator mass spectrometry (AMS) dates, sometimes paired or tripled, have been obtained on samples of various origin, foodcrusts, or visible charred deposits adhering to the surfaces of ceramic vessel walls were also dated and investigated for stable isotope signals. The results argue for a significant freshwater component in the food processed in ceramic vessels during the Subneolithic and Neolithic. Paired dating of ungulate and human bones at the Spiginas and Donkalnis cemeteries (6300–1900 cal BC) does not suggest an FRE, although stable isotope data on human bone collagen strongly suggest a large input of freshwater food in the diet. An FRE in the order of 320–510 yr was estimated for the Sventoji paleolagoon around 3000 cal BC. At the same time, the FRE of the Curonian Lagoon could be larger as implied by large apparent 14 C ages of modern pike-perch (981 ± 30 BP) and bream (738 ± 30 BP) bones as well as “foodcrust” offsets (650–530 yr) at Nida (3500–2500 cal BC). An MRE of 190 ± 43 yr was estimated for the southeastern coast of the Littorina Sea according to offsets between dates of seal bones and terrestrial samples at Nida and Sventoji. Any FRE at Lake Kretuonas remains uncertain due to the limited work to date. DOI: 10.2458/azu_rc.57.18447

Ultra-Small Graphitization Reactors for Ultra-Microscale 14C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Abstract: In response to the increasing demand for 14 C analysis of samples containing less than 25 µg C, ultra-small graphitization reactors with an internal volume of ~0.8 mL were developed at NOSAMS. For samples containing 6 to 25 µg C, these reactors convert CO 2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. Graphite targets produced with the ultra-small reactors are measured by using the Cs sputter source on the CFAMS instrument at NOSAMS where beam current was proportional to sample mass. We investigated the contribution of blank carbon from the ultra-small reactors and estimate it to be 0.3 ± 0.1 µg C with an Fm value of 0.43 ± 0.3. We also describe equations for blank correction and propagation of error associated with this correction. With a few exceptions for samples in the range of 6 to 7 µg C, we show that corrected Fm values agree with expected Fm values within uncertainty for samples containing 6–100 µg C. DOI: 10.2458/azu_rc.57.18118

Radiocarbon Dating Shows an Early Appearance of Philistine Material Culture in Tell es-Safi/Gath, Philistia

Abstract: The Late Bronze Age to Iron Age transition in the coastal southern Levant involves a major cultural change, which is characterized, among other things, by the appearance of Philistine pottery locally produced in styles derived from outside the Levant. This transition in the coastal southern Levant is conventionally dated to the 12th century BC, based on historical and archaeological artifacts associated with the Philistine pottery. Radiocarbon dating can provide a more precise independent absolute chronology for this transition, but dating for the period under discussion is complicated by the wiggles and relatively flat slope in the calibration curve, which significantly reduce precision. An additional complication is that the stratigraphic record below and above the transition at this site, as well as at most other sites in the region, is far from complete. We thus used a variety of microarchaeological techniques to improve our understanding of the stratigraphy, and to ensure that the locations with datable short-lived materials were only derived from primary contexts, which could be related directly to the associated material culture. The 14C dates were modeled using Bayesian statistics that incorporate the stratigraphic information. Using this integrative approach, we date the appearance of the Philistine pottery in Tell es-Safi/Gath in the 13th century BC.

New Data on Marine Radiocarbon Reservoir Effect in the Eastern Adriatic Based on Pre-Bomb Marine Organisms from the Intertidal Zone and Shallow Sea

Abstract: Radiocarbon analyses of 14 modern, pre-bomb marine organisms collected between AD 1836 and 1946 along the eastern Adriatic coast were performed. The 14 C ages of five algal and nine mollusk samples were measured by accelerator mass spectrometry (AMS). Marine 14 C reservoir ages (R) and regional offsets (∆R) were calculated and compared. The marine reservoir ages of shells and algae significantly differ, even though both inhabit the hard substrate from the intertidal zone to shallow sea. Coralline algae had a considerably lower reservoir age (355 ± 34 14 C yr) and ∆R value (–9 ± 34 14 C yr) than mollusks (R 513 ± 53 14 C yr; ∆R 154 ± 52 14 C yr), though the variability of R was high in both groups. Although the microlocations of pre-bomb samples were not known and the studied mollusk species are able to inhabit marine or estuarine environments, it can be assumed that they were not significantly influenced by a freshwater admixture, due to their δ 13 C values being mostly in the marine range. However, as the entire eastern Adriatic is formed in carbonates, mollusk shells could be influenced by limestone-depleted 14 C. In examining new data together with previously published data, the marine reservoir effect (MRE) for the Adriatic area is estimated to be 424 ± 57 14 C yr (∆R is 77 ± 57 14 C yr). Without mussel shells, the estimated MRE is 378 ± 44 14 C yr (∆R is 28 ± 45 14 C yr). The presented values are comparable to the MREs and mean ∆Rs obtained for the Mediterranean by other authors. DOI: 10.2458/azu_rc.57.18452

Freshwater reservoir effect on redating of eurasian steppe cultures: first results for eneolithic and early bronze age northeast kazakhstan

Abstract: Freshwater reservoir effects (FRE) can cause problems when radiocarbon dating human skeletal material from the Eurasian steppe. This article presents the first results of research into the extent of the FRE in the sites of Borly 4 (Eneolithic) and Shauke 1 and 8b (Early Bronze Age), northeastern Kazakhstan. Accelerator mass spectrometry (AMS) 14 C dating and stable isotope (δ 13 C, δ 15 N) analysis of associated groups of samples (32 samples, 11 groups in total) demonstrate the following: (a) the diet of the humans and fauna analyzed was based on the C 3 foodchain with no evidence of a C 4 plant (such as millet) contribution; aquatic resources apparently were a continuous dietary feature for the humans; (b) the first 14 C dates obtained for the Upper and Middle Irtysh River region attribute the Eneolithic period of the area to the 34th to 30th centuries BC, and the Early Bronze Age to the 25th to 20th centuries BC, with a ~450-yr hiatus between the two periods; (c) the maximum fish-herbivore freshwater reservoir offset observed equals 301 ± 47 14 C yr. As such, 14 C dates from aquatic and human samples from the area need to be interpreted with caution as they are likely to be affected by the offset (i.e. appear older). The article also discusses the effect of a sodium hydroxide (NaOH) wash on δ 13 C, δ 15 N, C:N atomic levels and collagen yields of the bone samples. Our results indicate a minor but significant effect of NaOH treatment only on C:N atomic ratios of the samples. DOI: 10.2458/azu_rc.57.18431

14C Variations in Pre-Bomb Nearshore Habitats of the Florida Panhandle, USA

Abstract: This article presents radiocarbon data for known-age, pre-bomb marine gastropods, Busycon sinistrum and Strombus alatus , collected between AD 1924 and 1946 from nearshore environments of the Florida Panhandle, on the northern Gulf of Mexico. Δ 14 C was measured in whole crushed juvenile specimens ( n = 7) and terminal edges of adult specimens ( n = 6). A subsample of adult specimens ( n = 3) was subjected to additional, intrashell sampling to observe short-term variability in 14 C conditions. Δ 14 C values were consistent within and among B. sinistrum specimens, and we propose a reservoir age offset (ΔR) of –9 ± 25 14 C yr for B. sinistrum from the northwest coast of Florida. S. alatus shells exhibited significant variability from one individual to another, and also within individual specimens. ΔR values for S. alatus range from –3 ± 30 to 659 ± 30 14 C yr. These differences may result from a combination of factors, including subregional variability in inputs of 14 C-depleted waters and life-history factors including mobility, mode of feeding, and ontogenetic niche shifts. DOI: 10.2458/azu_rc.57.18353

King David’s City at Khirbet Qeiyafa: Results of the Second Radiocarbon Dating Project

Abstract: Seventeen samples of burnt olive pits discovered inside a jar in the destruction layer of the Iron Age city of Khirbet Qeiyafa were analyzed by accelerator mass spectrometry (AMS) radiocarbon dating. Of these, four were halved and sent to two different laboratories to minimize laboratory bias. The dating of these samples is ~1000 BC. Khirbet Qeiyafa is currently the earliest known example of a fortified city in the Kingdom of Judah and contributes direct evidence to the heated debate on the biblical narrative relating to King David. Was he the real historical ruler of an urbanized state-level society in the early 10th century BC or was this level of social development reached only at the end of the 8th century BC? We can conclude that there were indeed fortified centers in the Davidic kingdom from the studies presented. In addition, the dating of Khirbet Qeiyafa has far-reaching implications for the entire Levant. The discovery of Cypriot pottery at the site connects the 14 C datings to Cyprus and the renewal of maritime trade between the island and the mainland in the Iron Age. A stone temple model from Khirbet Qeiyafa, decorated with triglyphs and a recessed doorframe, points to an early date for the development of this typical royal architecture of the Iron Age Levant. DOI: 10.2458/azu_rc.57.17961

A Process- and Provenance-Based Attempt to Unravel Inconsistent Radiocarbon Chronologies in Lake Sediments: An Example from Lake Heihai, North Tibetan Plateau (China)

Abstract: Aquatic macrophytes from a lacustrine environment are highly prone to a reservoir effect, resulting in an overestimation of age. This is often caused by the incorporation of dissolved carbon (CO 2 and HCO 3 – ) through photosynthesis from lake waters that have a different 14 C activity than the atmosphere. The atmosphere-water disparity is often produced by a mixing of carbon between the water body and its terrestrial surroundings, a process highly prone to temporal variations. Thus, only a comprehensive understanding of the 14 C budget over time enables a reliable chronology of lacustrine records. We studied lacustrine sediments from Lake Heihai on the northern Tibetan Plateau with a recent reservoir effect of 6465 ± 75 14 C yr as estimated from accelerator mass spectrometry (AMS) dating of three living aquatic plants. Age inversions in a well-laminated composite core from the lake suggest that the reservoir effect markedly changed over the depositional period. In the lower part of the core, an excellent correlation was observed between the allochthonous input of dolomite and the inverse 14 C ages, indicating the incorporation of dissolved 14 C-dead carbon from a limestone catchment in the plant material. For the upper part of the core, sediment recycling of Holocene high-stand deposits may have further contributed to the reservoir effect. These findings give rise to a reliable process- and provenance-based chronology within a confidence interval supported by 137 Cs measurements and magnetostratigraphic investigations. Our results highlight the need to identify the interactions of lakes with their surroundings to estimate reservoir-corrected ages in lacustrine settings. DOI: 10.2458/azu_rc.57.18221

Young, Old, and Weathered Carbon—Part 2: Using Radiocarbon and Stable Isotopes to Identify Terrestrial Carbon Support of the Food Web in an Alkaline, Humic Lake

Abstract: Carbon (C) and nitrogen (N) stable isotope analysis (SIA) has been used to identify the terrestrial subsidy of freshwater food webs. However, SIA fails to differentiate between the contributions of old and recently fixed terrestrial C and consequently cannot fully determine the source, age, and biochemical quality of terrestrial carbon. Natural abundance radiocarbon (∆ 14 C) was used to examine the age and origin of carbon in Lower Lough Erne, Northern Ireland. 14 C and stable isotope values were obtained from invertebrate, algae, and fish samples, and the results indicate that terrestrial organic C is evident at all trophic levels. High winter δ 15 N values in calanoid zooplankton (δ 15 N = 24‰) relative to phytoplankton and particulate organic matter (δ 15 N = 6‰ and 12‰, respectively) may reflect several microbial trophic levels between terrestrial C and calanoid invertebrates. Winter and summer calanoid ∆ 14 C values show a seasonal switch between autochthonous and terrestrial carbon sources. Fish ∆ 14 C values indicate terrestrial support at the highest trophic levels in littoral and pelagic food webs. 14 C therefore is useful in attributing the source of carbon in freshwater in addition to tracing the pathway of terrestrial carbon through the food web. DOI: 10.2458/azu_rc.57.18355

Potential Use of Archaeological Snail Shells for the Calculation of Local Marine Reservoir Effect

Abstract: Shellmounds are archaeological sites found across the Brazilian coast and form an important record of the human occupation of this area during the Holocene. The presence of both terrestrial and marine remains within the same archaeological context enables the comparison of different carbon reservoirs. There is only a small number of similar studies for the coast of south-southeastern Brazil. Previous work was based on the analysis of pre-bomb shells from museum collections and paired charcoal/marine shells from archaeological sites. This article assesses the potential use of terrestrial shells as representative of atmospheric carbon reservoir in the calculation of the marine reservoir effect (MRE) of the southeastern Brazilian coast. The presence of both terrestrial and marine shells over several archaeological layers represents a great potential for calculating reservoir corrections and their temporal variation. DOI: 10.2458/azu_rc.57.18365

Marine radiocarbon reservoir values in southern california estuaries: interspecies, latitudinal, and interannual variability

Abstract: Many studies use radiocarbon dates on estuarine shell material to build age-depth models of sediment accumulation in estuaries in California, USA. Marine 14 C ages are typically older than dates from contemporaneous terrestrial carbon and local offsets (∆R) from the global average marine offset need to be calculated to ensure the accuracy of calibrated dates. We used accelerator mass spectrometry (AMS) 14 C dating on 40 pre-1950 salt marsh snail and clam shells previously collected from four California estuaries. The average ∆R and standard deviation of 217 ± 129 14 C yr is consistent with previous calculations using mixed estuarine and marine samples, although the standard deviation and resulting age uncertainty was higher for our estuarine calculations than previous studies. There was a slight but significant difference ( p = 0.024) in ∆R between epifaunal snails (∆R = 171 ± 154 14 C yr) and infaunal clams (∆R = 263 ± 77 14 C yr), as well as between samples from individual estuaries. However, a closer examination of the data shows that even for the same species, at the same estuary, ∆R can vary as much as ~500 14 C yr. In some cases, the bulk of this variation occurs between samples collected by different collectors at different times, potentially indicating time dependence in carbon sources and ∆R variation. These variations could also be attributed to differences in collection location within a single estuary and resulting spatial differences in carbon sources. Intertidal specimens located in the high marsh may have lower ∆R than fully marine counterparts because of increased terrestrial 14 C input. The large variations in ∆R here highlight the need for conservative chronological interpretations, as well as the assumption of wide uncertainties, when dating samples from estuarine sources. DOI: 10.2458/azu_rc.57.18389

Marine reservoir corrections on the southeastern coast of brazil: paired samples from the saquarema shellmound

Abstract: The Saquarema archaeological site, on the Atlantic coast of the Rio de Janeiro State, is one of many shellmounds built on the Brazilian coast by hunter-gatherer populations during the Holocene. We used archaeological material from this site with the aim of evaluating the marine reservoir effect (MRE) in the region. Radiocarbon ages of 45 marine and 6 terrestrial samples from this shellmound provided data for assessing the MRE and the influences of freshwater and seasonal coastal marine upwelling in this specific locality. Samples of charcoal, fish otoliths, and mollusk shells were analyzed and the 14 C dates were modeled in the OxCal platform to determine the marine reservoir correction. The result obtained is R = 265 ± 70 14 C yr and the offset ΔR was found to be –140 ± 66 14 C yr. To support the accuracy of this value for correcting conventional 14 C marine ages, taxonomic analyses of the samples were performed. DOI: 10.2458/azu_rc.57.18404

Radiocarbon and the Archaeological Record: An Integrative Approach for Building an Absolute Chronology for the Late Bronze and Iron Ages of Israel

Abstract: The establishment of an absolute chronology for the Late Bronze and Iron Ages in the southern Levant would make it possible to use changes in material culture in order to study the impact of trade, dissemination of knowledge, and the impact of climate on historical processes. To achieve this, a detailed absolute chronology is needed for individual sites and on a regional scale with a resolution that can differentiate events within a century. To realize this challenging goal, only samples from well-established primary contexts ought to be studied. Such primary contexts (with “dating assemblages”) can be identified by combining macroscopic with microscopic observations. Chronological studies at the sites of Qubur el-Walaydah, Tel es-Safi, and in particular, Megiddo, demonstrate that high-resolution dating can be achieved, with very few outliers in the data sets. The major limitation on applying this approach is the fact that we are currently constrained to dating short-lived samples (charred seeds and olive pits) and collagen from bones. Thus, an immediate goal of radiocarbon research is to develop the ability to date other short-lived materials, such as organic material occluded in siliceous plant phytoliths, wood ash, and possibly organic residues preserved in pottery vessels. DOI: 10.2458/azu_rc.57.18554

Subsistence continuity linked to consumption of marine protein in the formative period in the interfluvic coast of northern Chile: re-assessing contacts with agropastoral groups from highlands

Abstract: From material culture evidence dating as early as 7500 cal BC, it has been established that populations from the interfluvic coast in northern Chile adapted to a maritime economic livelihood. During the 2nd millennium BC, local populations began to experience major social changes arising mainly from an increase in contacts with agropastoral populations from the highlands of the Andes. New radiocarbon data and stable isotope (δ 15 N col , δ 13 C col , and δ 13 C ap ) analyses of human bone remains from interfluvic coastal individuals were obtained. The data showed that these individuals, at the time of contact with highland populations, maintained a mode of subsistence relying principally on marine protein. This suggests that, although instances of social change may have arisen, the livelihoods linked to the consumption of marine resources would have remained constant, demonstrating a high degree of resistance in changing local lifestyles. DOI: 10.2458/azu_rc.57.18448

Sources of Dissolved Inorganic Carbon in Two Small Streams with Different Bedrock Geology: Insights from Carbon Isotopes

Abstract: Radiocarbon natural abundances ( Δ 14 C ) are being increasingly used to trace carbon cycling in stream ecosystems. To understand the ultimate sources of carbon, we determined the stable carbon isotope ratios (δ 13 C) and Δ 14 C values of dissolved inorganic and organic carbon (DIC and DOC, respectively) and of particulate organic carbon (POC) in two small streams in central Japan, one of which flows over limestone bedrock (Seri) and the other does not (Fudoji). Investigations over four seasons revealed that the Δ 14 C values of the DIC (from –238‰ to –174‰ for Seri and –23‰ to +10‰ for Fudoji) were less variable than those of the other carbon fractions (DOC: from –400‰ to –138‰ for Seri and –2‰ to +103‰ for Fudoji; POC: from –164‰ to –60‰ for Seri and –55‰ to +37‰ for Fudoji). Based on mass balance calculations using the δ 13 C and Δ 14 C values, the proportions of carbon in the DIC originated from (1) atmospheric CO 2 were 47% to 57% for Seri and 74% to 90% for Fudoji, (2) organic matter degradation were 29% to 35% for Seri and 4% to 21% for Fudoji, and (3) carbonate rock were 14% to 22% for Seri and 4% to 6% for Fudoji. We compared the results with previous studies that had been conducted in larger rivers and showed that in small streams, the dissolution of atmospheric CO 2 and weathering of carbonate rock are more important factors in the carbon cycling than the biological degradation of organic matter. DOI: 10.2458/azu_rc.57.18348

Bayesian Chronological Modeling of SunWatch, a Fort Ancient Village in Dayton, Ohio

Abstract: Radiocarbon results from houses, pits, and burials at the SunWatch site, Dayton, Ohio, are presented within an interpretative Bayesian statistical framework. The primary model incorporates dates from archaeological features in an unordered phase and uses charcoal outlier modeling (Bronk Ramsey 2009b) to account for issues of wood charcoal 14 C dates predating their context. The results of the primary model estimate occupation lasted for 1–245 yr ( 95% probability ), starting in cal AD 1175–1385 ( 95% probability ) and ending in cal AD 1330–1470 ( 95% probability ). An alternative model was created by placing the 14 C dates into two unordered phases corresponding with horizontal stratigraphic relationships or distinct groups of artifacts thought to be temporally diagnostic. The results of the alternative model further suggest that there is some temporal separation between Group 1 and Group 2, which seems more likely in the event of a multicomponent occupation. Overall, the modeling results provide chronology estimates for SunWatch that are more accurate and precise than that provided in earlier studies. While it is difficult to determine with certainty if SunWatch had a single-component or multicomponent occupation, it is clear that SunWatch’s occupation lasted until the second half of the AD 1300s. DOI: 10.2458/azu_rc.57.18179

High-Precision Atmospheric 14CO2 Measurement at the Rafter Radiocarbon Laboratory

Abstract: This article describes a new capability for high-precision 14 C measurement of CO 2 from air at the Rafter Radiocarbon Laboratory, GNS Science, New Zealand. We evaluate the short-term within-wheel repeatability and long-term between-wheel repeatability from measurements of multiple aliquots of control materials sourced from whole air. Samples are typically measured to 650,000 14 C counts, providing a nominal accelerator mass spectrometry (AMS) statistical uncertainty of 1.3‰. No additional uncertainty is required to explain the within-wheel variability. An additional uncertainty factor is needed to explain the long-term repeatability spanning multiple measurement wheels, bringing the overall repeatability to 1.8‰, comparable to other laboratories measuring air materials to high precision. This additional uncertainty factor appears to be due to variability in the measured 14 C content of OxI primary standard targets, likely from the combustion process. We observe an offset of 1.4‰ in our samples relative to those measured by the University of Colorado INSTAAR, comparable to interlaboratory offsets observed in recent intercomparison exercises. DOI: 10.2458/azu_rc.57.18390

Flame-Sealed Tube Graphitization Using Zinc as the Sole Reduction Agent: Precision Improvement of EnvironMICADAS 14C Measurements on Graphite Targets

Abstract: The flame-sealed tube zinc reduction graphitization method has been successfully adapted and optimized for radiocarbon measurements on EnvironMICADAS in the Institute for Nuclear Research of the Hungarian Academy of Sciences, Hertelendi Laboratory of Environmental Studies (ATOMKI HLES). To reduce the cost and treatment time of producing graphite targets from samples of about 1 mg carbon content, we have omitted the titanium hydride (TiH 2 ) reagent and used a decreased amount of zinc as the sole reductant in our new method. These changes have also helped to eliminate methane formation during the graphitization processes as well as to recover higher ion current at the same background level. These conditions have led to improved efficiency in the 14 C measurements; furthermore, the instrument background level remained sufficiently low (<49,000 yr BP). After determining the optimum parameters of the new Zn graphitization method (2.5 mg Fe powder, 15.0 mg Zn powder, 10 hr graphitization at 550°C in heating block, reaction cells with reagent pretreated at 300°C for 1 hr), verification of the accuracy was carried out by the preparation and measurement of IAEA standard samples (C2, C6, C7, C8) with known 14 C activity. The sensitivity of the method for gas contamination was tested and determined by comparing the results to measurements of reserved portions of previously processed real samples. DOI: 10.2458/azu_rc.57.18193

Radiocarbon Dates and Stable Isotope Data from the Early Bronze Age Burials in Riigiküla I and Kivisaare Settlement Sites, Estonia

Abstract: Four inhumations from Kivisaare and Riigikula I settlement and burial sites were dated in the course of a project about hunter-gatherer mortuary practices in Estonia, as they were believed to belong to the Stone Age. However, these burials appear to be Early Bronze Age inhumations instead, and thus are discussed separately in the present article. These burials are the first evidence in Estonia of a long-lasting tradition of inhumations without any visible aboveground structures. As the archaeology of the Early Bronze Age in Estonia is poorly known, these four inhumations contribute immensely to our understanding about this time period. Moreover, stable isotope values show that these people had a more terrestrial subsistence strategy than Stone Age hunter-gatherers. Nevertheless, aquatic resources were probably still significant components of their diet, particularly at Kivisaare, and the radiocarbon dates could therefore be subject to significant freshwater reservoir effects. This creates ambiguity in the chronological relationship of these four individuals to burials in stone-cist graves, which are attributed to the Late Bronze Age and which appear to be associated with fully agricultural communities. DOI: 10.2458/azu_rc.57.18459

Iron Age Pigs: New Evidence on Their Origin and Role in Forming Identity Boundaries

Abstract: This article reviews recent studies of pigs in the Iron Age in the southern Levant. The studies were carried out as part of the European Research Council–funded Ancient Israel project, with the aim of examining questions of identity and ethnic boundaries, with special emphasis on Philistia and ancient Israel. On the Philistine side, the results show a dichotomy in pork consumption between urban centers and the rural sector, and suggest that European domestic pigs were brought to the Levant by the Sea Peoples, most probably to secure the supply of meat. Reviewed with previous evidence, we suggest that economic motivation was the driving force for pork consumption and abandonment. Regarding ancient Israel, new studies show that avoiding pork was a widespread phenomenon of much of the Iron Age in both the highland and the lowlands outside of Philistia. They also point to a rise in pork consumption in lowlands sites of the Northern Kingdom in the Iron IIB and suggest a link between this phenomenon and the early consolidation of the taboo on pigs in Judah in late-monarchic times. DOI: 10.2458/azu_rc.57.18564