Radiocarbon Dating

Radiocarbon dating is the most widely used dating technique in the world. Recent advances in Accelerator Mass Spectrometry (AMS) and sample preparation techniques have reduced the sample-size requirements by a factor of 1000 and decreased the measurement time from weeks to minutes. Today, it is estimated that more than 90 percent of all measurements made on accelerator mass spectrometers are for radiocarbon age dates. The production of 14 C in the atmosphere varies through time due to changes in the Earth's geomagnetic field intensity and in its concentration, which is regulated by the carbon cycle. As a result of these two variables, a radiocarbon age is not equivalent to a calendar age. Four decades of joint research by the dendrochronology and radiocarbon communities have produced a radiocarbon calibration data set of remarkable precision and accuracy extending from the present to approximately 12,000 calendar years before present. This paper presents high precision paired 230 Th/ 234 U/ 238 U and 14 C age determinations on pristine coral samples that enable us to extend the radiocarbon calibration curve from 12,000 to 50,000 years before present. We developed a statistical model to properly estimate sample age conversion from radiocarbon years to calendar years, taking full account of combined errors in input ages and calibration uncertainties. Our radiocarbon calibration program is publicly accessible at: http://www.radiocarbon.LDEO.columbia.edu/ along with full documentation of the samples, data, and our statistical calibration model.

The Whakatane Tephra, a rhyolitic tephra erupted ca. 5500 cal. BP from Okataina Volcanic Centre, central North Island, has been identified on the Chatham Islands which lie ~900 km east of Christchurch, New Zealand. The visible tephra layer, ~5 mm in thickness and preserved within peat on Pitt Island, was identified using both radiocarbon dating and analysis of glass shards by electron microprobe. Whakatane Tephra is the first Holocene tephra to be identified on the Chatham Islands, and it is the most distal Holocene tephra yet recorded in the New Zealand region, being ~850 km from source. The Pitt Island occurrence extends the tephra's dispersal area markedly, by an order of magnitude, possibly to ~300,000 km 2 . An estimated dispersal index (D) of approximately 10 5 km 2 indicates that the eruption generated a very high plinian column, possibly exceeding ~30 km in height, with strong winds blowing the ash plume southeastwards.This new discovery of distal Whakatane Tephra as a thin but visible layer strongly implies that cryptotephras are likely to bepreserved on the Chatham Islands and within adjacent ocean floor sediments. Therefore the potential exists to develop enhanced cryptotephrostratigraphic records from these distal areas, which in turn would help facilitate precise correlation via tephrochronology of palaeoenvironmental records (such as NZ-INTIMATE) from mainland New Zealand, the southwest Pacific Ocean, and the Chatham Islands.

The late Quaternary sedimentary history of the continental margin off Portugal was reconstructed from sediment gravity cores. Hemipelagic sedimentation (lithofacies A) was dominant during glacial times. It was interrupted periodically by deposition of shelf-and upper-slope-derived silty and sandy terrigenous material by dilute turbidity currents (lithofacies B and C), ice-rafted debris during distinct periods of breakdown of North Atlantic ice sheets (Heinrich events, lithofacies D) and large amounts of pteropods (lithofacies F). Settling of biogenic particulate material (lithofacies E) prevailed during the Holocene, when sea level and sea surface temperatures were high and terrigenous shelf-input was low.

Angkorian temples are characterised by one or more encircling moats that are excavated into the alluvial substrate. As a key part of the overall design of the temple, the moats are important symbolically and are presumed to be contemporaneous with the associated temple. They also represent important depositional basins for sediment and other materials and can therefore yield vertical profiles of sediment that has accumulated since the moat was originally excavated. Unconformities in these moat profiles can be dated absolutely using smallsample, high-precision AMS radiocarbon techniques. These unconformities are likely to represent periodic re-excavation or maintenance of the moat and therefore indicate the presence of large, presumably centrally organised workforces. In some instances, presumed anthropogenic unconformities occur centuries after Angkor was supposedly abandoned. In this way, radiocarbon dates themselves are being used as a proxy indicator of cultural activity and are being used to challenge the historiography of Angkor's famous demise.

The South Caucasus occupies the divide between ancient Mesopotamia and prehistoric Europe, and was thus crucial in the development of Old World societies. Chronologies for the region, however, have lacked the definition achieved in surrounding areas. Concentrating on the Tsaghkahovit Plain of northwestern Armenia, Project ArAGATS's multi-site radiocarbon dataset has now produced Bayesian modelling, which provides tight chronometric support for tracing the transmission of technology, population movement and social developments that shaped the Eurasian Bronze and Iron Ages.

Accurate geochronologies are the key for comparison of palaeoclimate records. In order to clarify problems concerning the geochronology of glacier fluctuations we dated palaeosols in moraines in the Kebnekaise mountain region of Swedish Lapland. These palaeosols already have been dated several years ago using bulk samples of the palaeosols and yielded ages of 6180–5790 and 2750–2100 cal yr BP. In an attempt to evaluate the sources of contamination associated with bulk samples these soils were re-dated by using Coleoptera fragments, Cenococcum geophilum spores, humic acids and woody plant tissues. The new dates reveal that the two palaeosols found within the moraines represent much longer periods of time than was previously assumed. Soil formation periods can be distinguished for periods 7800–7580, 6300–4080, 2450–2000 and 1170–740 cal yr BP. These age groups point to differentiated soil formation processes, resedimentation, bioturbation and/or cryoturbation. The results show that dated terrestrial macrofossils from glacial moraines indicate climate changes that are in accordance with other proxy records in northern and central Scandinavia and in certain times off-phase with glacier fluctuations in southern maritime Norway. This throws light on possible changing interaction of forcing factors during the Holocene.

A 9000-year carbonate-rich sediment sequence from a small hard-water lake in northernmost Sweden was studied by means of multi-component stable carbon isotope analysis. Radiocarbon dating of different sediment fractions provides chronologic control and reveals a rather constant hard-water effect through time, suggesting that the lake has remained hydrologically open throughout the Holocene. Successive depletion of 13 C in fine-grained calcite and carbonate shells during the early Holocene correlate with a change in catchment vegetation from pioneer herb communities to boreal forest. The vegetational change and associated soil development likely gave rise to an increased supply of 13 C-depleted carbon dioxide in groundwater recharging the lake. This process is therefore believed to be the main cause of decreasing values of 13 C in dissolved inorganic carbon of the lake and thereby in limnic carbonates. Strongly 13 C-depleted sedimentary organic matter may be related to enhanced kinetic fractionation during photosynthetic assimilation by means of proton pumping in Characean algae. This interpretation is supported by a substantial offset between 13 C of DIC as recorded by mollusc shells and 13 C of fine-grained calcite.

We analyze statistically representative samples of radiocarbon dates from key Early Neolithic sites in Central Europe belonging to the Linear Pottery Ceramic Culture (LBK), and of pottery-bearing cultures on East European Plain (Yelshanian, Rakushechnyi Yar, Buh-Dniestrian, Serteya and boreal East European Plain). The dates from the LBK sites form a statistically homogeneous set with the probability distribution similar to a single-date Gaussian curve. This implies that the duration of the spread of the LBK is shorter than the available temporal resolution of the radiocarbon dating; therefore, the rate of spread must be larger than 4 km/yr, in agreement with earlier estimates. The East European sites exhibit a broad probability distribution of dates. We identify in these data a spatio-temporal sequence from southeast to northwest , which implies the rate of spread of the initial pottery-making of the order of 1.6 km/yr, comparable to the average rate of spread of the Neolithic in Western and Central Europe. We argue that this spatio-temporal sequence is consistent with an idea that the tradition of the initial pottery-making on East European Plain developed under an early impulse from the Eastern Steppe.

The paper gives a historical outline of the views on the correlation between radiocarbon and archaeological
chronology and presents the results of the first statistical analysis of large arrays of radiocarbon dates obtained
over a long period of time in different laboratories for the East Gravettian campsites of Kostenki 1
(layer 1), Avdeevo, Zaraysk and Khotylevo 2. Chronological episodes of populating the campsites have
been identified, and appear to ref lect a multistage (or stepwise) accumulation of the cultural layer. The
studies have shown the feasibility of conducting statistical analysis alongside with investigating the microstratigraphy
and overall spatial structure of a site, since that allows cross-validation of the results.

Methods for Bayesian statistical analysis of stratigraphically related radiocarbon dates have been in use for over a decade. This paper extends these techniques to stratigraphically related ESR dates, allowing estimation of the dates of events not directly dated. A hierarchical model of the uncertainties in ESR dating is developed, to account for the correlation of error terms between samples. Using the new method, an analysis is made of the dating at Border Cave, Kwa Zulu Natal, South Africa. The results for individual dates and the dating of layer boundaries are more precise than previously obtained. The hominid fossils BC1 and BC2 are placed at either 71–91 ka (95% highest posterior density—hpd) or 152–171 ka (95% hpd) depending on the stratigraphic provenance assigned. BC3 is dated to 66–90 ka and BC5 to 61–72 ka (both 95% hpd). The estimated duration of the Howieson's Poort industry at Border Cave is demonstrated to have significant uncertainty, and the ESR dates, even with the increased precision of this analysis, are unable to decide between hypotheses that the industry lasted 10 ka and that it lasted 20 ka.

Radiocarbon-dated elevated marine deposits and the record of anthropogenic and natural debris in archaeological deposits on the west coast of South Africa indicate that significant coastal remodelling has taken place in the past 4300 years in response to sea level change. Geological and archaeological investigation of elevated deposits of sub-fossil shell, abandoned lagoons, and washover bars has shown that many

Paleoenvironmental reconstruction combining data from diatom, pollen, macrophytic, and archaeological analyses had not been attempted previously for coastal Peru. We analyzed two radiocarbondated sediment cores extracted from the "sacred" Urpi Kocha Lagoon at the pre-Hispanic religious center of Pachacamac (ca. AD 350e1533), near Lima, to characterize the paleoenvironment of the site. The data reveal an environmental history characterized by alternating periods of severe drought and catastrophic flood. Recurrent pulses with distinctive sediment, diatom, pollen, and macrophytic characteristics reflecting variations in water depth, substrate, turbidity and salinity, usually contain a thick basal sandy storm deposit overlain by thin organic accumulations of peat, gyttja, and snails. The most intense of these disturbance pulses, when correlated with pollen, plant macrofossils, radiocarbon dates, and regional proxy data, provide local evidence of four major floods associated with sustained, catastrophic El Niño events, tsunamis and/or severe storms in the Andean highlands over the last 2000 years.

One of the largest long-runout landslides in the modern history of the Czech Republic originated on the southern slopes of the Girová Mountain (Outer Western Carpathians) at the end of extreme rainfalls in May 2010. The structurally predisposed Girová Mountain rockslide occurred very quickly within fault-weakened, deeply-weathered flysch bedrock. Its main phase, during which a wedge-like block collapsed in the upper part of slope, lasted for a few hours. The overloaded slope collapsed and its motion lasted for the following 3 days. The May 2010 Girová Mountain rockslide is an excellent case of a recurrent long-runout landslide nested within a deep-seated gravitational slope deformation with a long history of Late Quaternary mass movements. The chronology of slope failures within the studied slope was reconstructed by means of radiocarbon dating and dendrogeomorphological analysis. At least one Holocene long-runout landslide (7.4 cal ka BP) and several smaller failures (~1.5 and~0.6 cal ka BP) preceded this recent catastrophic failure. Dendrogeomorphological analysis showed that the failure had been preceded by at least 80-year-long creep movement that accelerated over the years due to extreme rainfall events. Despite the fact that extreme precipitation of May 2010 represented the last incremental change before catastrophic collapse of the slope, its main reason was gradual weakening of rock massif and concentrated creeping (with some accelerated phases) in the upper part of the slope deformation.

Introduction The Oslofjord region in SE-Norway has been subject to steady glacio-isostatic uplift during the whole Holocene. The final retreat of the ice at the termination of the last glacial took place in this area between 13,900 (retreat from Hvaler ice-marginal ridge) and 11,500 years BP (retreat from Ski ice-marginal ridge). Since then, the area has been characterized by continuous

Lakes are excellent repositories of air-borne and especially stream-borne materials. It has long been recognised that lake sediments contain a strong record of catchment soils via the inputs of minerogenic and chemical erosional products. To these may be added a variety of palaeoecological indicators including pollen, fungi, Sphagnum leaves and faunal remains. Pollen analysis, in particular, enables land use change to be assessed over many millennia and demonstrates the landscape impacts of woodland clearance, grazing and crop cultivation. Radiocarbon dating provides a chronology for environmental and agricultural change and acts as an indicator of erosion in its own right. The use of such indicators to reconstruct past instances and patterns of erosion is demonstrated with reference mainly to 50 British and Irish lake sites and especially those which have produced signals of erosion in the form of accelerated sediment accumulation and inversed or reversed sequences of radiocarbon dates during the mid and late Holocene.

During the Late Holocene, a number of new technologies (single-piece fishhooks, toggling harpoons, plank canoes, etc.) are thought to have significantly enhanced the fishing capabilities of California coastal peoples. The single-piece fishhook, perhaps the most common of these artifacts, appears to correlate with a regional intensification of marine fishing and a period of increased population growth. Determining the antiquity of the single-piece fishhook has been complicated by a variety of taphonomic and methodological factors. Consequently, age estimates for the initial appearance of these artifacts range from about 5500 to 2500 cal-. To help clarify the chronology of this important artifact type, we had eight of the potentially oldest shell fishhooks in the region AMS radiocarbon dated. These dates indicate that the single-piece shell fishhook appeared throughout the southern and central California Coast by at least 2500 cal-. Our data illustrate the utility of direct AMS dating of individual artifacts as a method of documenting site disturbances (bioturbation, historical land use, etc.) and refining artifact, site, and regional chronologies.

This paper discusses the Bronze Age archeological finds discovered
during the course of the follow up road works around
Cerdanyola del Vallès Synchrotron, near Barelona. This consists of
a grouping of three pits: a funerary hypogeum, with six individuals
buried and two silos. The study of the unearthed pottery, as well
as the attainment of four radiocarbon dating have allowed to lay
down the chronological framework in a period of consolidation
of the Bronze Age. It also includes an interpretation of the ritual
character documented in one of the pits near the burial structure.
It deserves special attention the discovery of a fragment of an
engraved stone, perhaps part of a stele.

Although here in DuPage we are very far from the Pacific, this class will help you become literate with regards to the cultures and histories of Pacific island societies. Each person living in the Pacific is part of an ongoing story of movement, settlement, and adaptation to island environments that has produced remarkable histories of cultural accomplishment and political struggle. Although relatively small in population, the Pacific islands span one-third of the globe, encompass about one fourth of the world’s languages, and include some of its most unique ecological zones. The Pacific has been an object of western world interest and fantasy since the earliest days of exploration, and continues to generate all kinds of exotic images, whether of paradise, of “disappearing” cultures, or threatened ecologies.

In this course, we will be concerned both with the experience of indigenous communities and with representations of the Pacific generated inside and outside the region. Pacific prehistory of travel began with Pleistocene movement of Homo sapiens sapiens, continued with Lapita colonization which gave way to the far-flung voyages of Polynesian navigators. Pacific indigenous settlement was then followed by waves of European explorers, missionaries, and colonizers. These movements have produced dramatic, and often tragic, stories of cultural encounter and transformation. The experience of Pacific communities, past and present, has much to teach us about living in communities that contend with global flows of people, culture, and capital. Today island travelers continue to move through national capitals and metropolitan centers from Honolulu to Los Angeles and Auckland, fashioning new forms and identities that extend the boundaries of the Pacific.

Volcanic ash (tephra) erupted from the frequently active Campi Flegrei volcano forms layers in many palaeoenvironmental archives across Italy and the Mediterranean. Proximal deposits of 50 of the post-15 ka eruptions have been thoroughly sampled and analysed to produce a complete database of glass compositions (>1900 analyses) to aid identification of these units. The deposits of individual eruptions are compositionally diverse and this variability is often greater than that observed between different units. Many of the tephra units do not have a unique glass chemistry, with compositionally similar tephra often erupted over long periods of time (1000s years). Thus, glass chemistry alone is not enough to robustly correlate most of the tephra from Campi Flegrei, especially in the last 10 kyrs. In order to reliably correlate the eruption units it is important to take into account the stratigraphy, chronology, magnitude, and dispersal of the eruptions, which has been collated to aid identification. An updated chronology is also presented, which was constrained using Bayesian analysis (OxCal) of published radiocarbon dates and 40 Ar/ 39 Ar ages. All the data presented can be employed to help correlate post-15 ka tephra units preserved in archaeological and Holocene palaeoenvironmental archives. The new database of proximal glass compositions has been used to correlate proximal volcanic deposits through to distal tephra layers in the Lago di Monticchio record and these correlations provide information on eruption stratigraphy and the tempo of volcanism at Campi Flegrei.

The past few hundred years have seen large fluctuations in atmospheric 14 C concentration. In part, these have been the result of natural factors, including the climatic changes of the Little Ice Age, and the Spö rer and Maunder solar activity minima. In addition, however, changes in human activity since the middle of the 19th century have released 14 C-free CO 2 to the atmosphere. Moreover, between c. 1955 and c. 1963, atmospheric nuclear weapon testing resulted in a dramatic increase in the concentration of 14 C in the atmosphere. This was followed by a significant decrease in atmospheric 14 C as restrictions on nuclear weapon testing began to take effect and as rapid exchange occurred between the atmosphere and other carbon reservoirs. The large fluctuations in atmospheric 14 C that occurred prior to 1955 mean that a single radiocarbon date may yield an imprecise calibrated age consisting of several possible age ranges. This difficulty may be overcome by obtaining a series of 14 C dates from a sequence and either wigglematching these dates to a radiocarbon calibration curve or using additional information on dated materials and their surrounding environment to narrow the calibrated age ranges associated with each 14 C date. For the period since 1955 (the bomb-pulse period), significant differences in atmospheric 14 C levels between consecutive years offer the possibility of dating recent samples with a resolution of from one to a few years. These approaches to dating the recent past are illustrated using examples from peats, lake and salt marsh sediments, tree rings, marine organisms and speleothems.

Between 1984 and 1995 over 450 organic samples were collected from monuments built during the Old and Middle Kingdoms. The most suitable samples were selected for dating. The purpose was to establish a radiocarbon chronology with samples from secure context and collected with the careful techniques required for 14 C samples. This chronology is compared to the historical chronology established by reconstructing written documentation.

Two archaeological specimens of peyote buttons, i.e. dried tops of the cactus Lophophora williamsii (Lem.) Coulter, from the collection of the Witte Museum in San Antonio, was subjected to radiocarbon dating and alkaloid analysis. The samples were presumably found in Shumla Cave No. 5 on the Rio Grande, Texas. Radiocarbon dating shows that the calibrated 14C age of the weighted mean of the two individual dated samples corresponds to the calendric time interval 3780-3660 BC (one sigma significance). Alkaloid extraction yielded approximately 2% of alkaloids. Analysis with thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS) led to the identification of mescaline in both samples. No other peyote alkaloids could be identified.

In the Sigatoka Valley on Viti Levu Island in Fiji, three independent studies of last-millennium environmental and human-societal changes suggest that these were driven largely by the climate and sea-level changes of the AD 1300 Event. Establishment dates for interior fortified hilltop (or cave) settlements show that a significant number were established during or shortly after the AD 1300 Event, probably in response to primarily food shortages arising from sea-level fall (affecting coastal populations) and water-table fall (affecting coastal and inland populations). Charcoal concentrations in valley-floor sediments formed as a result of largely human burning of vegetation associated with the establishment of inland hilltop settlements; radiocarbon dates from these charcoals also suggest significant numbers of such settlements being established during or shortly after the AD 1300 Event. The main dune at the Sigatoka River mouth is underlain by the 'Level 3' palaeosol, dated to the AD 1300 Event, which implies that thereafter an abrupt and sustained increase in suspended fluvial sediment, associated in increased inland population, began to build the high dunes visible today. This study provides a well-constrained example of the effects that the AD 1300 Event had on Pacific Islands and their people.

. Ž . Several long sediment cores max. 12 m from various parts up to 150 km apart of Lake Onega, Russian Karelia, have been studied for lithology, varve chronology and palaeomagnetism. The two longest varve records from the central basin contain 1300 varves. These indicate the length of the deglaciation period from these localities to the north of Lake Onega, where the drainage of glacial meltwaters was directed towards the White Sea and the deposition of varves in the Onega basin terminated. An estimate of the duration of deglaciation of the whole Onega basin is 1500 years. Natural remanent Ž . magnetization NRM is strong and stable in these sediments and accurately records changes in the Earth's magnetic field. A distinct change in the magnetic field, when the declination shifted from east to west by at least 608 in 350 varve years, is clearly identifiable in all cores. This palaeomagnetic feature was used for core to core correlation together with other variations in magnetic parameters and widely distributed lithological marker horizons. On the basis of the correlations between the cores and calibration of AMS radiocarbon dates from varves obtained from the northern archipelago of Lake Onega, the age of the westerly declination peak is dated to 13 090 cal. BP and accordingly the deglaciation of the Onega basin took place between 14 250 and 12 750 " 100 cal. BP. The westerly declination peak was also recognized earlier by Bakhmutov and Zagniy in the Helyla varved clay sequence near Sortavala on the northern shore of Lake Ladoga. Helyla iss ituated outside the Salpausselka end moraines and the accumulation of varved clays continued there 1500 years after thë declination peak, up until the drainage of the Baltic Ice Lake, which more or less coincides with the ice margin retreat from Salpausselka II end moraine and the termination of the Younger Dryas event. The date thus arrived at for this event is 11 590 " 100 cal. BP, close to the recent results from Greenland ice cores and from varved lake sediments and tree rings from Central Europe. It is further suggested that the formation of the major Younger Dryas end moraines, the Finnish Salpausselka I and Salpausselka II and their correlatives in Russian Karelia, took place between 12 250 and 11 590 calendarÿ ears ago, clearly earlier than earlier estimated through correlation with the Swedish varve chronology. q

A series of piston cores from Flathead Lake, Montana, USA and a new radiocarbon date from the sedimentary record provide the basis for describing sedimentary processes related to deglaciation of the Flathead Lobe of the Cordilleran Ice Sheet and for interpreting the retreat history of the lobe. The oldest part of Flathead Lake sediment core records is Late Pleistocene in age and consists of cm-scale rhythmites of silt and clay, interpreted here as annual varves. Each varve contains a light-colored coarser-grained portion, inferred to represent deposition during peak annual runoff, and a darker-colored finer-grained portion interpreted to represent sediment accumulation during seasonal low-flow conditions. The coarser-grained portions, especially in the stratigraphically older sections of each core, contain sedimentary structures that reflect traction transport. Based on these sedimentary structures, their facies characteristics, and their spatial distribution within the lake, we interpret the thicker, light-colored portion of each varve to be deposited by hyperpycnal flows caused by seasonal melt events rather than more classic turbidity currents. Immediately overlying Late Pleistocene rhythmites in all Flathead Lake cores is a unique, significantly coarser-grained dm-scale silt bed with a median grain size up to 50 µm. This silt bed has a sharp, locally erosional base and fines upward but does not contain any other sedimentary structures. In contrast to the rhythmites, we interpret this silt bed to represent a single, short-lived catastrophic sedimentation event generated by a large glacial outburst flood. Overlying this distinct bed are several other cm-scale beds of mainly silt that exhibit a basal upward-coarsening followed by an upward-fining median grain size profile. We interpret these beds and their grain size trends as reflecting the rising and falling hydrograph limbs of outburst floods derived from more distal sources located in the upstream parts of the upper Flathead watershed. The sediment record from Flathead Lake, together with results from geologic and geomorphologic 1:24,000 scale mapping around the lake margins, provide a series of constraints regarding the paleogeographic evolution of the area during deglaciation. Overall upward-thinning and upward-fining of the varved portion of the sediment core records reflects northward retreat of the southern Flathead Lobe ice margin starting at latest 14,475 ± 150 cal yr BP, the depositional age of the oldest varve in any of our cores. The depositional age of silt beds overlying the varved records is constrained as between 14,150 ± 150 cal yr BP and 13,180 ± 120 cal yr BP. Within the available chronostratigraphic constraints, the outburst floods interpreted to have delivered this silt to the Flathead Lake basin also downcut a bedrock nick point below the Flathead Lake outlet, oriented a series of large boulders downstream, and deposited a series of large flood bars on the lower Flathead River floodplain.

On the basis of radiocarbon dates recently obtained for a trench in the back part of Gorham's Cave, Gibraltar, it has been claimed that Neanderthals survived in the region until at least 28,000 and probably as late as 24,000 radiocarbon years ago . The stratigraphic and archaeological context of these results, however, does not warrant such an interpretation, because of the microscopic nature of the dated samples, the wide scatter in the dates obtained, and the lack of any correlation between age and stratigraphic depth. An Early Upper Palaeolithic occupation

This study estimates the maximum and minimum degrees of autocompaction for radiocarbon-dated Holocene mangrove sediments in Singapore, in order to correct apparent sediment accretion rates for the effects of sediment compression due to autocompaction. Relationships developed for a suite of modern (surface) sediment samples between bulk density, particle-size distribution, and organic matter content were used to estimate the initial (uncompacted) bulk density of buried and variably compressed Holocene sediments, based on the grain-size distribution and organic matter content of the sediment. The difference between measured (compacted) and initial (uncompacted) bulk density of each buried sediment interval can be interpreted as the amount of length shortening experienced by each interval since burial. This allows the elevation of samples selected for 14C dating to be corrected for the effects of autocompaction of the underlying sediment sequence, so that accurate estimates of vertical...

We reconstruct the Holocene range fluctuations of the European pond turtle (Emys orbicularis) for northern and Central Europe. Based on 529 subfossil records and radiocarbon dating of critical finds, we provide evidence that E. orbicularis experienced a rapid range expansion with Holocene warming. Phylogeographic data argue for a colonization of northern and Central Europe from a glacial refuge located in the south-eastern Balkans. Already in the Late Preboreal (9100-8600 cal BC) the species occurred in northern Central Europe and was widespread in Denmark and southern Sweden (Ska˚ne) during the Boreal (8600-7100 cal BC). The maximum range extension occurred during the Holocene climatic optimum (Atlantic: 7100-3750 cal BC), with records in southern England, middle Sweden, and northern Estonia. After the early Subboreal (3750-1750 cal BC) northern populations collapsed, coinciding with a climatic cooling and oceanization. Northern populations were most likely established via long distance dispersal (rafting using rivers debouching in the North and Baltic Seas); after northern Europe was reached, a minimum dispersal of 50 km per 100 years may be hypothesized for the Boreal. r ), with several investigations reviewing data for certain countries (e.g.

Cette étude évalue l’abondance des graines d’Erythrophleum suaveolens dans la banque de semences du sol des forêts denses humides d’Afrique centrale. Les travaux ont été menés au Nord-Congo dans deux types forestiers : la forêt à Celtis sur des sols argilo-sableux à sablo-argileux et la forêt à Manilkara sur des sols sableux. Les tiges d’E. suaveolens (dhp ≥ 10 cm) ont été inventoriées dans deux blocs de 400 ha, et les structures diamétriques de leurs populations ont été comparées. En outre, 80 fosses (2 x 40 fosses par type de forêt) ont été creusées au pied de 20 arbres (10 par forêt), sur trois couches contiguës de 10 cm chacune, soit à une profondeur totale de 30 cm, et l’abondance des graines dans la banque de semences du sol a été évaluée. La dormance des graines récoltées a été testée par des essais de germination après traitement au H2SO4 et cinq graines prélevées jusqu'à une profondeur de 20 cm dans la forêt à Celtis ont été utilisées pour estimer leur âge par spectroscopie de masse par accélérateur (AMS). Dans les deux types forestiers, les structures diamétriques présentent une distribution gaussienne, illustrant un déficit de régénération. Alors que les densités de tiges (dhp ≥ 10 cm) sont proches, avec 0,85 et 1,05 tige/ha respectivement, dans la forêt à Celtis et la forêt à Manilkara. Les densités de graines sont significativement plus élevées dans la forêt à Celtis (8,55 graines/m2) que dans la forêt à Manilkara (0,15 graine/m2). Le pourcentage maximum de germination obtenu était de 19,1 % pour des graines n’ayant subi aucun traitement. Les lots traités à l’acide ont présenté de moindres taux de germination. Ces graines semblent pouvoir se conserver une dizaine d’années au moins dans la banque du sol. Les facteurs pouvant influencer les variations de densité des graines sont discutés et des recommandations sylvicoles sont formulées.

A multidisciplinary study has been carried out on a 51 m long core, drilled on coastal lowlands near the Albegna River (Tuscany, Central Italy). Both sedimentological and faunal analyses (ostracods and molluscs) indicate a coastal lagoon environment repeatedly influenced both by the rising Holocene sea and the Albegna River alluvial inflow. δ13C, δ18O, Mg/Ca, Sr/Ca and 87Sr/86Sr analyses were performed on Cyprideis torosa shells in order to detail the influence of Albegna River freshwater on the coastal lagoon water. The analytical data illustrate the difficulties of using geochemical proxies in marginal marine settings. Four radiocarbon dates provide a chronostratigraphy for the early Holocene part of the core. The data are used to reconstruct Late Pleistocene to early Holocene palaeoenvironments along this part of the coast and show the development of freshwater environments followed by a coastal brackish lagoon formed in response to the initial Holocene rapid rise in relative sea level. An attempt is made to relate sediments and age data from the core to the relative sea-level curve for the Tyrrhenian Sea.

Radiocarbon-dated pollen sequences from two areas of Bodmin Moor—Rough Tor in the north-west and the East Moor—are presented and the evidence for settlement in the prehistoric period on the moor considered. The nature and extent of human impact in the two areas ...

The Middle to Upper Paleolithic transition is a key period of change in the prehistory of the Old World and one of the most studied issues in paleoanthropology, as the nature of the transition(s) is still, after at least a century of archaeological research, largely unknown. Many of the issues at stake in the transition relate to the problem of building a reliable chronology for this period, which is at the limits of the radiocarbon method. The papers in this volume show that much progress has been made in our chronological knowledge of significant aspects of the transition, such as the age of the most recent Neandertal fossils and the earliest modern human remains in Europe, and the inferred overlap between the Châtelperronian and the Aurignacian. At the same time, the volume also shows where the chronological database for the period 40 to 30 ka 14C BP is flawed and that significant contextual and methodological problems have been underestimated in a number of studies of the biological and cultural changes during this crucial period. Chronology is employed by paleoanthropologists to relate the record of the Middle to Upper Paleolithic transition to major biological and cultural developments. This paper takes a broader paleoanthropological perspective and attempts to evaluate and, to some degree, synthesize the main results of these proceedings, while also presenting a brief discussion of the Middle and Upper Paleolithic archaeological and fossil records, and possible explanations for the differences between the two, focusing on the role of differences in the ecology of Neandertals and early European modern humans.