Christopher Bronk Ramsey

University of Oxford | OX · School of Archaeology

Tree-ring analysis of sixteen samples from oak timbers excavated at Alverstone Marshes, Isle of Wight in 2005 clustered ten of these samples into three groups, which consisted of two, five and three timbers respectively. These sample, and the six unmatched timbers, however, are all currently undated by dendrochronology. Radiocarbon dating of Cluste...

In 1996, a rescue excavation was carried out by Tees Archaeology after the discovery of human bones during building work. The excavated Early Bronze Age cemetery is unusual for the range of mortuary treatment in evidence and for the quantity and variety of the grave goods in one particular grave, Burial 5. Here the body of a young to middle-aged wo...

Anthropogenically-driven climate warming and land use change are the main causes of an ongoing decrease in global biodiversity. It is unclear how ecosystems, particularly freshwater habitats, will respond to such continuous and potentially intensifying disruptions. Here we analyse how different components of terrestrial and aquatic ecosystems respo...

The Must Farm pile-dwelling site is an extraordinarily well-preserved Late Bronze Age settlement in Cambridgeshire built over a freshwater palaeochannel that was destroyed by a catastrophic fire shortly after its construction. Predating the settlement was a double-alignment of massive oak piles. This technical archive report on the tree-ring and ra...

Understanding the temporal and spatial environmental response to past climate change during the Last Glacial-Interglacial Transition (LGIT, 16-8 ka) across Europe relies on precise chronologies for palaeoenvironmental records. Tephra layers (volcanic ash) are a powerful chronological tool to synchronise disparate records across the continent. Yet,...

This document is a technical archive report on the radiocarbon dating of carbonised plant macrofossils in support of research undertaken by the Historic England Environmental Studies branch. It includes full details of 32 radiocarbon measurements obtained from Woodcutts, Iwerne, Rotherley, Durrington Walls, Cuckoo Stone, Coneybury Henge, Lockington...

Erfkroon (28.868° S, 25.594° E) is a large open-air archaeological and paleontological site with Later Stone Age (LSA) and Middle Stone Age (MSA) artifacts eroding out of four terraces formed in the Modder River valley ~60km northwest of Bloemfontein, South Africa. The oldest terrace, the Wolwespruit Terrace has not been dated and lacks artifacts a...

The Marine20 radiocarbon ( ¹⁴ C) age calibration curve, and all earlier marine ¹⁴ C calibration curves from the IntCal group, must be used extremely cautiously for the calibration of marine ¹⁴ C samples from polar regions (outside ∼ 40ºS–40ºN) during glacial periods. Calibrating polar ¹⁴ C marine samples from glacial periods against any Marine cali...

The IntCal family of radiocarbon ( ¹⁴ C) calibration curves is based on research spanning more than three decades. The IntCal group have collated the ¹⁴ C and calendar age data (mostly derived from primary publications with other types of data and meta-data) and, since 2010, made them available for other sorts of analysis through an open-access dat...

The FeedSax project combined bioarchaeological data with evidence from settlement archaeology to investigate how, when and why the expansion of arable farming occurred between the 8th-13th centuries in England. It has generated and released a vast, multi-faceted archaeological dataset both to underpin its own published findings and to support furth...

Analyses of radiocarbon dates (all corrected for the freshwater reservoir effect) and associated stable isotope values obtained from the skeletal remains of ~560 individuals provide many new insights about Middle Holocene hunter-gatherers (HG) of the Cis-Baikal region, Eastern Siberia. The new radiocarbon evidence clarifies the culture history of t...

Hunter-gatherer archaeology typically focusses on the details of subsistence strategies and material culture and, in the case of cemeteries, on various aspects of mortuary practices, beliefs, and social differentiation. This paper aims to look rather at patterns of change over time and space in how past hunter-gatherer cemeteries were used from Lat...

Prehistoric shell mounds can be useful for the quantification of the radiocarbon marine reservoir effect (MRE) and, at the same time, knowledge about the MRE allows for the establishment of robust chronologies for these sites. This creates a loop in which the archaeological setting has a dual role: it is part of both the method and the application....

Radiocarbon ( ¹⁴ C) concentrations in the oceans are different from those in the atmosphere. Understanding these ocean-atmospheric ¹⁴ C differences is important both to estimate the calendar ages of samples which obtained their ¹⁴ C in the marine environment, and to investigate the carbon cycle. The Marine20 radiocarbon age calibration curve is cre...

Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present...

The Marine20 radiocarbon (14C) age calibration curve, and all earlier marine radiocarbon calibration curves from the IntCal group, must be used extremely cautiously for the calibration of marine 14C samples from polar regions (outside ~ 40ºS – 40ºN) during glacial periods. Calibrating polar 14C marine samples from glacial periods against any Marine...

A new chronological study of the LBK in the central Polish lowlands shows that it emerged later, lasted for a shorter period, and ended sooner than has been supposed up till now. LBK communities emerged, probably in the middle of the 53 rd century cal BC, to form an enclave in the central Polish lowlands, probably as a result of colonisation from l...

The North Atlantic region experienced abrupt high-amplitude cooling at the onset of the Younger Dryas stadial. However, due to chronological uncertainties in the available terrestrial records it is unclear whether terrestrial ecosystem response to this event was instantaneous and spatially synchronous, or whether regional or time-transgressive lags...

Geomagnetic excursions represent the dynamic nature of the geodynamo. Accumulated palaeomagnetic records indicate that such excursions are dominated by dipolar-fields, but exhibit different structures. Here we report a palaeomagnetic record from the varved sediments of Lake Suigetsu, central Japan, which reveals fine structures in the Laschamp Excu...

This paper summarises research on freshwater reservoir effects (FRE) in the Baikal region and their impact on the radiocarbon dating of human remains. Varying relationships are seen between human δ¹³C and δ¹⁵N values and ¹⁴C offsets in paired human-terrestrial mammal radiocarbon dates from the same graves in the different microregions of Cis-Baikal...

Yuzhniy Oleniy Ostrov in Karelia, northwest Russia, is one of the largest Early Holocene cemeteries in northern Eurasia, with 177 burials recovered in excavations in the 1930s; originally, more than 400 graves may have been present. A new radiocarbon dating programme, taking into account a correction for freshwater reservoir effects, suggests that...

Our paper about the impacts of the Laschamps Geomagnetic Excursion 42,000 years ago has provoked considerable scientific and public interest, particularly in the so-called Adams Event associated with the initial transition of the magnetic poles. Although we welcome the opportunity to discuss our new ideas, Hawks’ assertions of misrepresentation are...

Our study on the exact timing and the potential climatic, environmental, and evolutionary consequences of the Laschamps Geomagnetic Excursion has generated the hypothesis that geomagnetism represents an unrecognized driver in environmental and evolutionary change. It is important for this hypothesis to be tested with new data, and encouragingly, no...

Using carbon-14 Carbon-14 or radiocarbon, a radioactive isotope produced in the upper atmosphere by cosmic rays, is rapidly incorporated into the terrestrial carbon cycle and provides a way to calculate the age of carbon-bearing materials as old as 55,000 years. Heaton et al . review recent progress that has allowed the construction of better radio...

A considerable amount of bioarchaeological research – including AMS 14C dating and stable carbon and nitrogen isotope analyses (δ13C and δ15N) – has been undertaken on the hunter-gatherers from the area west of Lake Baikal, known as Cis-Baikal. No such work has previously been reported for the east side of the lake, Trans-Baikal. Here, we present n...

Sea-level change is thought to influence the frequencies of volcanic eruptions on glacial to interglacial timescales. However, the underlying physical processes and their importance relative to other influences (e.g. magma recharge rates), remain poorly understood. Here we compare a ~360 kyr long record of effusive and explosive eruptions from the...

Despite eastern Africa being a key location in the emergence of Homo sapiens and their subsequent dispersal out of Africa, there is a paucity of long, well-dated climate records in the region to contextualize this history. To address this issue, we dated a ∼293 m long composite sediment core from Chew Bahir, south Ethiopia, using three independent...

Stable oxygen isotope dendrochronology is an effective precision-dating method for fast grown, invariant (complacent) tree-rings and for trees growing in moist, temperate climatic regions where growth may not be strongly controlled by climate. The method works because trees preserve a strong common isotopic signal, from summer precipitation, and th...

Reconstructions of climatic and environmental conditions can contribute to current debates about the factors that influenced early human dispersal within and beyond Africa. Here we analyse a 200,000-year multi-proxy paleoclimate record from Chew Bahir, a tectonic lake basin in the southern Ethiopian rift. Our record reveals two modes of climate cha...

Leads, lags, or synchronies in climatic events among different regions are key to understanding mechanisms of climate change, as they provide insights into the causal linkages among components of the climate system. The well-studied transition from the Lateglacial to early Holocene (ca. 16–10 ka) contains several abrupt climatic shifts, making this...

The Dating the Earliest Neolithic Ceramics of Wessex project was part of a training programme in the Bayesian chronological modelling of radiocarbon dates funded by Historic England. Its original scope was to target ceramic assemblages for dating in four areas: the Middle Thames, the Avebury area, the Stonehenge area of Salisbury Plain, and an area...

Analyses of radiocarbon dates (all corrected for the freshwater reservoir effect) and associated stable isotope values obtained from the skeletal remains of ~650 individuals provide many new insights about Middle Holocene hunter–gatherers (HGs) of the Cis-Baikal region, Eastern Siberia. The new radiocarbon evidence clarifies the culture history of...

Hunter-gatherer archaeology typically focusses on the details of subsistence strategies and material culture and, in the case of cemeteries, on various aspects of mortuary practices, beliefs, and social differentiation. This paper aims to look rather at patterns of change over time and space in how past hunter-gatherer cemeteries were used from Lat...

Reversing the field Do terrestrial geomagnetic field reversals have an effect on Earth's climate? Cooper et al. created a precisely dated radiocarbon record around the time of the Laschamps geomagnetic reversal about 41,000 years ago from the rings of New Zealand swamp kauri trees. This record reveals a substantial increase in the carbon-14 content...

Supplementary Material for 'A global environmental crisis 42,000 years ago' Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the...

The limestone islands of the Bahamian archipelago provide a challenging environment for human settlement, one that was not taken up until after AD 700. The analysis of human skeletal remains offers new insights into how this challenge was met. A substantial program of AMS ¹⁴C dating on pre-Columbian humans (n = 66) provides a robust chronological f...

The Glastonbury Lake Village in Somerset, UK, is made up of 90 mounds comprising 40 roundhouses. Excavations between 1892 and 1907 revealed Iron Age structural and material remains unparalleled in Western Europe. The settlement's exact chronology, however, has remained uncertain. Here, the authors present a programme of radiocarbon and dendro-chron...

Several scientific expeditions surveyed the ocean during the 19th century, gathering a wealth of interdisciplinary data as well as samples of different kinds. The latter are currently held by museums worldwide, and are the subject of study in different sciences, offering a unique opportunity to access information which is not readily available else...

This paper, presents formally modelled date estimates for the sequence of Lengyel funerary pottery in western Hungary, eastern Austria and south-west Slovakia. It is an extension of the dating and modelling already carried out by the project, The Times of Their Lives (ToTL), on the major Lengyel aggregation, including burials, at Alsónyék-Bátaszék...

Chronological modelling of radiocarbon dates from Stonehenge

Radiocarbon dating and Bayesian chronological modelling have provided precise new dating for the henge monument of Mount Pleasant in Dorset, excavated in 1970-1. A total of 59 radiocarbon dates are now available for the site and modelling of these has provided a revised sequence for the henge enclosure and its various constituent parts: the timber...

The new IntCal20 radiocarbon record continues decades of successful practice by employing one calibration curve as an approximation for different regions across the hemisphere. Here we investigate three radiocarbon time-series of archaeological and historical importance from the Mediterranean-Anatolian region, which indicate, or may include, offset...

To create a reliable radiocarbon calibration curve, one needs not only high-quality data but also a robust statistical methodology. The unique aspects of much of the calibration data provide considerable modeling challenges and require a made-to-measure approach to curve construction that accurately represents and adapts to these individualities, b...

The concentration of radiocarbon ( ¹⁴ C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their ¹⁴ C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the i...

Analysis was undertaken on samples from the roof and ceiling structures of the hall and cross-wing resulting in the construction of three site sequences: GRLNSQ01 contains 34 oak samples and spans the period AD 1268–1440; GRLNSQ02 contains 13 oak samples and spans the period AD 1412–1579; GRLNSQ03 contains six elm samples but remains undated. In th...

The future response of the Antarctic ice sheet to rising temperatures remains highly uncertain. A useful period for assessing the sensitivity of Antarctica to warming is the Last Interglacial (LIG) (129 to 116 ky), which experienced warmer polar temperatures and higher global mean sea level (GMSL) (+6 to 11 m) relative to present day. LIG sea level...

We test a recent prediction that stable carbon isotope ratios from UK oaks will display age-trends of more than 4‰ per century by measuring >5400 carbon isotope ratios from the late-wood alpha-cellulose of individual rings from 18 modern oak trees and 50 building timbers spanning the 9th–21st centuries. After a very short (c.5 years) juvenile phase...

Connecting calendar ages to radiocarbon ( ¹⁴ C) ages, i.e. constructing a calibration curve, requires ¹⁴ C samples that represent, or are closely connected to, atmospheric ¹⁴ C values and that can also be independently dated. In addition to these data, there is information that can serve as independent tests of the calibration curve. For example, i...

The Lake Baikal region of southern Siberia has a rich mortuary record that has provided the most comprehensive isotopic database for palaeodietary studies of north-temperate hunter-gatherers in the world, permitting more detailed reconstructions and finer-grained research questions than are usually possible. Building on previous work, this study co...

Oxygen isotope ratios from oak tree rings are used to extend the May–August precipitation totals of the England and Wales precipitation series back to 1201 ce. The agreement between instrumental and reconstructed values is unusually strong, with more than half of the variance explained and standard verification tests passed. The stability of this r...

Tree-ring analysis was undertaken on samples taken from the coach house/stables range, the castle tower, and the castle annexe resulting in the construction of a single site sequence representing two tiebeams from the tower. This site sequence could not be conclusively dated through dendrochronology alone but tentative dating obtained has now been...

Tree-ring analysis of samples taken from 15 Flemingate, Beverley, resulted in the construction of two site sequences: BEVGSQ01, a site sequence of 92 rings containing four samples, and BEVGSQ02, a 177-ring site sequence from two samples. Neither of these nor any of the ungrouped individual series could be securely dated using tree-ring analysis. Tr...

Tree-ring analysis of samples taken from The Guildhall resulted in the construction of four site sequences: BEVJSQ01, a site sequence of 197 rings containing four samples, BEVJSQ02, an 82-ring site sequence also containing four samples, and BEVJSQ03 and BEVJSQ04, site sequences of 84 rings and 63 rings respectively each of which contained two sampl...

Forty samples from the nave, south aisle, and porch of this church were subject to tree-ring dating; three of these also underwent radiocarbon and wiggle-match analysis. Three nave timbers were dendrochronologically dated to AD 1581--1606 and two to c AD 1616. A further nine timbers from this roof have now been dated by radiocarbon wiggle-matching...

The curves recommended for calibrating radiocarbon ( ¹⁴ C) dates into absolute dates have been updated. For calibrating atmospheric samples from the Northern Hemisphere, the new curve is called IntCal20. This is accompanied by associated curves SHCal20 for the Southern Hemisphere, and Marine20 for marine samples. In this “companion article” we disc...

A new isotopic method for dating oak and non-oak (elm) timbers is applied to samples from the portcullis windlass mechanism in the Byward Tower, Tower of London. This structure was previously sampled for ring width dendrochronology but failed to date. Successful application of the stable oxygen isotope dating method returns a felling date of winter...

Terrestrial plant macrofossils from the sedimentary record of Lake Suigetsu, Japan, provide the only quasi-continuous direct atmospheric record of radiocarbon ( ¹⁴ C) covering the last 50 ka cal BP (Bronk Ramsey et al. 2012). Since then, new high precision data have become available on U-Th dated speleothems from Hulu Cave China, covering the same...

In much of Europe, the advent of low-input cereal farming regimes between c.ad 800 and 1200 enabled landowners—lords—to amass wealth by greatly expanding the amount of land under cultivation and exploiting the labour of others. Scientific analysis of plant remains and animal bones from archaeological contexts is generating the first direct evidence...

We thank Helama and Matskovsky (2019, https://doi.org/10.1177/0959683616652709) for their interest in our work. They argue that we should use Regional Curve Standardization (RCS) to identify trends in our oxygen isotope series and to detrend them prior to climate reconstruction. We disagree.

The future response of the Antarctic ice sheet to rising temperatures remains highly uncertain. A useful period for assessing the sensitivity of Antarctica to warming is the Last Interglacial (LIG) (129 to 116 ky), which experienced warmer polar temperatures and higher global mean sea level (GMSL) (+6 to 9 m) relative to present day. LIG sea level...

The recent development of an oxygen isotope (δ¹⁸O) master chronology for south central England (1200–2000 AD) has successfully demonstrated reliable cross-dating between the master chronology and undated samples from vernacular and high-status buildings. The method is well suited to complacent, wide-ringed samples, which are commonplace throughout...

Sixteen timbers from worked wood and a tree stump excavated from Glastonbury Lake Village were submitted for tree-ring dating, Five oak samples, that had originally be excavated by Bulleid and Grey in 1896-7 but been reburied, were deemed suitable for analysis. Two sets of two samples (GLV 206 and 214, and GLV 207 and 213) crossmatched against each...

Radiocarbon and chronological modelling for Barrow Clump