Christopher B Ramsey
Biographic Data
| ID | 454 |
|---|---|
| NAME | Christopher B Ramsey |
| GIVEN NAMES | Christopher B |
| FAMILY NAME | Ramsey |
| SIGNATURE | RAMSEY C B |
| AFFILIATIONS | University of Oxford |
| ORCID | 0000-0002-8641-9309 |
| VERIFIED | Yes |
| TOTAL WORKS | 204 |
| TOTAL CITATIONS | 10388 |
| AUTHOR COUNT | 204 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1993 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 32 |
A compound-specific radiocarbon dating protocol for archaeological pottery at the Orau
Radiocarbon dating is essential for establishing robust chronologies in archaeological and paleoenvironmental contexts spanning the last 55,000 years. Pottery, pervasive in the archaeological record, offers a crucial framework for dating human activity during the Holocene. Traditionally, radiocarbon dating of pottery has relied on targeting carbonaceous inclusions such as organic temper or measuring stratigraphically associated materials like bon…
Ring‐Width Dendrochronology, Isotopic Dendrochronology and Radiocarbon Dating of Timbers From the Spire Scaffold of Salisbury Cathedral, Wiltshire, England
Ten timbers from the spire scaffold of Salisbury Cathedral were dated using a combination of ring‐width dendrochronology, stable oxygen isotopic dendrochronology and radiocarbon dating. Seven timbers were coeval and assigned a combined empirical felling date range of 1352–1378, which was further refined to 1351–1359 (OxCal 95.4%). These results would indicate that the scaffold was not a 1320s construction but instead built later in the 14th centu…
Establishing a Chronology for Roman and Post-Roman Stanwick, Northamptonshire
The programme of radiocarbon dating undertaken at Stanwick, Northamptonshire, demonstrates the value of scientific dating of Romano-British sites, including those with good pottery sequences and large numbers of datable coins and other finds. It has refined and clarified the chronology and phasing of the site, particularly in its final phase of occupation. It confirmed some of our original dating of the human burials, and showed other dates were …
Medieval Settlement Chronologies
A 350 14 C yr discrepancy between bone and tooth dates from the same grave at the Early Neolithic cemetery of Shamanka II, Lake Baikal, southern Siberia
A 350 14 C yr discrepancy was found between dates on postcranial remains and mandibular teeth on what was thought to be the same individual from the Early Neolithic cemetery of Shamanka II, Lake Baikal. Stable nitrogen isotope results suggested a major shift in diet between childhood (when the teeth formed) and adulthood (represented by the postcrania), which could have resulted in different 14 C ages through a freshwater reservoir effect. Subseq…
Localised land-use and maize agriculture by the pre-Columbian Casarabe Culture in Lowland Bolivia
Multiple pre-Columbian (pre-1492 CE) archaeological sites now challenge the traditional portrayal of Amazonia as a ‘pristine wilderness’. This is especially true within the forest-savanna mosaic landscapes of lowland Bolivia, where the pre-Columbian Casarabe Culture constructed hundreds of settlement mounds, integrated with a dense causeway-canal network – one of the most complex, stratified societies yet discovered in Amazonia. Excavations at pr…
Redefining SW Amazonian chronologies and pottery use at the Teotônio site
Radiocarbon Calibration
Temporal and spatial variation in radiocarbon ( 14 C) in the atmosphere has been the subject of investigation from the first pioneering work of Libby and Arnold. However, as the precision of measurements has improved, now by almost two orders of magnitude, what constitutes a significant variation has also changed. Furthermore, it has become possible to test degrees of variation over much longer timescales and with ever wider geographic coverage. …
Development of the Intcal Database
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 database. This has ensured transparency in terms of the data used in the construction of the ratified c…
Erfkroon, South Africa
Neolithic and Early Bronze Age of Cis-Baikal
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 the region by defining better the boundaries between the chronological (archaeological periods) and c…
Neolithic and Early Bronze Age of Cis-Baikal
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 Late Mesolithic to Early Bronze Age (~8600–3500 cal BP) in the Cis-Baikal region of Eastern Siberia. Th…
Feeding Anglo-Saxon England
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 further research
Referee statement
Referee statement in McKerracher, M. et al. 2023 Feeding Anglo-Saxon England: a bioarchaeological dataset for the study of early medieval agriculture (Data paper)
Assessing the 14 C Marine Reservoir Effect in Archaeological Contexts
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. Therefore, it is paramount to address these sites from both archaeological and environmental perspe…
Marine Radiocarbon Calibration in Polar Regions
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 calibration curve (Marine20 or any earlier product) using an estimate of ${\rm{\Delta R}}$ , the regiona…
A Response to Community Questions on the Marine20 Radiocarbon Age Calibration Curve
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 created to address these dual aims by providing a global-scale surface ocean record of radiocarbon from…
A history of the LBK in the central Polish lowlands
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 loess areas in the south of Poland. Settlement steadily intensified throughout the 52 nd century cal …
Turning eastward
Middle Holocene hunter–gatherers of Cis-Baikal, Eastern Siberia
Spatio-temporal patterns of cemetery use among Middle Holocene hunter-gatherers of Cis-Baikal, Eastern Siberia
Freshwater reservoir effects in Cis-Baikal
Oxygen isotope dating of oak and elm timbers from the portcullis windlass, Byward Tower, Tower of London
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 AD 1656/7 for the oak timbers used to construct the gear wheel and a date of after AD 1648 (terminu…
Are there enormous age-trends in stable carbon isotope ratios of oak tree rings
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 with slightly elevated values, the number of series that show rising and falling trends is almost e…
Longhouse times
In the central part of the main area of the Alsónyék complex investigated an LBK settlement was discovered. The features belonging to the LBK occupation were uncovered in subsites 10B, 11 and 5603. The location of houses could be determined by the long pits flanking presumed timber-framed constructions; postholes are very poorly preserved. Fifty house plans could be identified, most of them based on the long pits. Most Neolithic archaeologists ag…
Bayesian Analysis of Radiocarbon Dates
If radiocarbon measurements are to be used at all for chronological purposes, we have to use statistical methods for calibration. The most widely used method of calibration can be seen as a simple application of Bayesian statistics, which uses both the information from the new measurement and information from the 14 C calibration curve. In most dating applications, however, we have larger numbers of 14 C measurements and we wish to relate those t…
IntCal09 and Marine09 Radiocarbon Age Calibration Curves, 0-50,000 Years cal BP
The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14 C and calendar timescales as established in 2002. No change was made to the curves…
Intcal04 Terrestrial Radiocarbon Age Calibration, 0–26 Cal Kyr BP
A new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace IntCal98, which extended from 0–24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0–26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than IntCal98. Dendrochronologically-dated tree-ring samples cover the period f…
The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0–55 cal kBP)
Radiocarbon ( 14 C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14 C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth syste…
Radiocarbon Calibration and Analysis of Stratigraphy
People usually study the chronologies of archaeological sites and geological sequences using many different kinds of evidence, taking into account calibrated radiocarbon dates, other dating methods and stratigraphic information. Many individual case studies demonstrate the value of using statistical methods to combine these different types of information. I have developed a computer program, OxCal, running under Windows 3.1 (for IBM PCs), that wi…
Development of the Radiocarbon Calibration Program
This paper highlights some of the main developments to the radiocarbon calibration program, OxCal. In addition to many cosmetic changes, the latest version of OxCal uses some different algorithms for the treatment of multiple phases. The theoretical framework behind these is discussed and some model calculations demonstrated. Significant changes have also been made to the sampling algorithms used which improve the convergence of the Bayesian anal…
Dealing with Outliers and Offsets in Radiocarbon Dating
The wide availability of precise radiocarbon dates has allowed researchers in a number of disciplines to address chronological questions at a resolution which was not possible 10 or 20 years ago. The use of Bayesian statistics for the analysis of groups of dates is becoming a common way to integrate all of the 14 C evidence together. However, the models most often used make a number of assumptions that may not always be appropriate. In particular…
Current Pretreatment Methods for AMS Radiocarbon Dating at the Oxford Radiocarbon Accelerator Unit (Orau)
In this paper, we summarize the main chemical pretreatment protocols currently used for AMS radiocarbon dating at the Oxford Radiocarbon Accelerator Unit, updating the protocols last described by Hedges et al. (1989)
Recent and Planned Developments of the Program OxCal
OxCal is a widely used software package for the calibration of radiocarbon dates and the statistical analysis of 14 C and other chronological information. The program aims to make statistical methods easily available to researchers and students working in a range of different disciplines. This paper will look at the recent and planned developments of the package. The recent additions to the statistical methods are primarily aimed at providing mor…
Methods for Summarizing Radiocarbon Datasets
Bayesian models have proved very powerful in analyzing large datasets of radiocarbon ( 14 C) measurements from specific sites and in regional cultural or political models. These models require the prior for the underlying processes that are being described to be defined, including the distribution of underlying events. Chronological information is also incorporated into Bayesian models used in DNA research, with the use of Skyline plots to show d…
SHCal20 Southern Hemisphere Calibration, 0–55,000 Years cal BP
Early researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We de…
Improvements to the Pretreatment of Bone at Oxford
Bone is one of the most widely used materials for dating archaeological activity. It is also relatively difficult to pretreat effectively and new methods are an area of active research. The purpose of the chemical pretreatment of bone is to remove contaminants present from burial and to do so in a way which does not add any additional laboratory contaminant. To some extent, these two aims must be balanced since, on the whole, the more complex the…
Τesting models for the beginnings of the Aurignacian and the advent of figurative art and music
Marine20—The Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP)
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 internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-aver…
AMS Radiocarbon Dating of Ancient Bone Using Ultrafiltration
The Oxford Radiocarbon Accelerator Unit (ORAU) has used an ultrafiltration protocol to further purify gelatin from archaeological bone since 2000. In this paper, the methodology is described, and it is shown that, in many instances, ultrafiltration successfully removes low molecular weight contaminants that less rigorous methods may not. These contaminants can sometimes be of a different radiocarbon age and, unless removed, may produce erroneous …
Wiggle Matching’ Radiocarbon Dates
This paper covers three different methods of matching radiocarbon dates to the ‘wiggles’ of the calibration curve in those situations where the age difference between the 14 C dates is known. These methods are most often applied to tree-ring sequences. The simplest approach is to use a classical Chi-squared fit of the 14 C data to the 14 C curve. This gives the calendar date where the data fit best and allows tests of how good the fit is. The onl…
Bradshaw and Bayes
The importance of chronology is reasserted as a means to achieving history and a sense of temporality. A range of current methods for estimating the dates and durations of archaeological processes and events are considered, including visual inspection of graphs and tables of calibrated dates and the summing of the probability distributions of calibrated dates. These approaches are found wanting. The Bayesian statistical framework is introduced, a…
Marine04 Marine Radiocarbon Age Calibration, 0–26 Cal Kyr Bp
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring…
Towards High-Precision AMS
Precision and accuracy in accelerator mass spectrometry (AMS) dating relies on the systematic reduction of errors at all stages of the dating process, from sampling to AMS measurement. With new AMS systems providing much better precision and accuracy for the final stage of the process, we need to review the process as a whole to test the accuracy of reported results. A new High Voltage Engineering Europa (HVEE) AMS system was accepted at Oxford i…
Precision dating of the Palaeolithic
Quality Assurance of Ultrafiltered Bone Dating
Ultrafiltration of bone collagen provides a method of purification that can be very effective in reducing environmental contamination from soil-derived amino acids as well as removing degraded collagen or other short-chain proteins. The Oxford Radiocarbon Accelerator Unit (ORAU) first implemented ultrafiltration in the pretreatment of bone material for accelerator mass spectrometry (AMS) radiocarbon dating in 2000. However, the filters themselves…
Pre-screening techniques for identification of samples suitable for radiocarbon dating of poorly preserved bones
An Independent Chronology for British Bronze Age Metalwork
The paper presents and analyses 46 new radiocarbon measurements undertaken at the Oxford Radiocarbon Accelerator Unit with the aim of critically evaluating the existing chronology for Bronze Age metalwork. Samples chosen, from both old museum collections and more recent finds, were all organics in immediate physical contact with various types of bronze object; indeed the great majority were in direct functional association. Contextual integrity w…
Radiocarbon Dating
Radiocarbon dating has undergone a number of ‘revolutions’ in the past 50 years. This is in part because it is a field in continuous development, but perhaps more because of its profound impact on archaeology and the nature of interdisciplinary research. In order to understand the use of radiocarbon as a dating tool, it is necessary to understand the life cycle of radiocarbon, from its production in the upper atmosphere, through its sequestration…
Reevaluating the Age of the Iberomaurusian in Morocco
Radiocarbon Dates From the Oxford Ams System
Radiocarbon Dates From the Oxford Ams System
Comment (R. M. J.): the Pleistocene fauna from Steetley Wood Cave differs from any so far reported from Creswell Crags, less than 5 km to the south-west, in its limited range of speciesbear, wolf, fox, reindeer and a bovine (seemingly bison). In this it resembles the much larger faunal sample from Windy Knoll near Castleton, Derbyshire. The infinite age obtained offers no contradiction to the hypothesis that these and other equivalent assemblages…
Radiocarbon Dates From the Oxford Ams System
Radiocarbon Calibration and Analysis of Stratigraphy
People usually study the chronologies of archaeological sites and geological sequences using many different kinds of evidence, taking into account calibrated radiocarbon dates, other dating methods and stratigraphic information. Many individual case studies demonstrate the value of using statistical methods to combine these different types of information. I have developed a computer program, OxCal, running under Windows 3.1 (for IBM PCs), that wi…
Radiocarbon Dates From the Oxford Ams System
Radiocarbon Dates From the Oxford Ams System
This twentieth list of accelerator dates consists mainly of material dated since the beginning of 1993.but includes a number of measurements made earlier in the dating programme.The dates have been achieved by the methods described in Law and Hedges (1989), Hedges et ul.(1989; 1992).Determinations with OxA numbers greater than 2095 were measured on the CO, gas ion-source (Bronk and Hedges 1989) rather than on the previous iron-graphite system.In …
Radiocarbon Dates From the Oxford Ams System
Radiocarbon Dates From the Oxford Ams System
An Independent Chronology for British Bronze Age Metalwork
The paper presents and analyses 46 new radiocarbon measurements undertaken at the Oxford Radiocarbon Accelerator Unit with the aim of critically evaluating the existing chronology for Bronze Age metalwork. Samples chosen, from both old museum collections and more recent finds, were all organics in immediate physical contact with various types of bronze object; indeed the great majority were in direct functional association. Contextual integrity w…
An Ion Source for the HVEE 14 C Isotope Ratio Mass Spectrometer for Biomedical Applications
During the past two decades, accelerator mass spectrometry (AMS) has allowed major developments in many areas of geosciences and archaeology. In the near future, AMS should realize a similar potential in the field of biomedical research, leading ultimately to clinical applications. For such applications, the required instrument differs significantly from that presently used in the field of 14 C dating. Whereas the needed accuracy and sensitivity …
An Experiment to Refute the Likelihood of Cellulose Carboxylation
To test the hypothesis that cellulose in linen can be carboxylated at high temperatures in the presence of CO 2 , water and silver, we heated two aliquots of cellulose extracted from old wood in glass ampoules, adding Ag powder to one to test its potential action as a catalyst for the carboxylation reaction. AMS measurement of the heated aliquots showed no statistically significant difference in 14 C content from the “uncarboxylated” cellulose. W…
Methodological Issues in the 14 C Dating of Rock Paintings
Chemical and isotopic analyses have been made of pigment samples from two separate rock art sites in Argentina. The purpose of the study has been to establish the feasibility of extracting carbonaceous material from the samples which will permit reliable radiocarbon dates for the time of painting. The two sites, Catamarca and Rio Negro, present quite different problems. Most of the paper is concerned with Catamarca, and here we have shown that th…
Radiocarbon Dates From the Oxford Ams System
This twenty-third list of accelerator dates consists mainly of material dated since the beginning of 1994.but includes a number of measurements made earlier in the dating programme.The dates have been achieved by the methods described in Law and Hedges (1989), Hedges et uI.(1989; 1992).Determinations with OxA numbers greater than 2095 were measured on the CO, gas ion-source (Bronk and Hedges 1989) rather than on the previous iron-graphite system.…
Radiocarbon Dates From the Oxford Ams System
This twenty-fourth list of accelerator dates consists mainly of material dated since the beginning of 1994, but includes a number of measurements made earlier in the dating programme. It also includes, for the first time, a list of samples measured incollaboration with the Centre de Datation par le Radiocarbone de Lyon: Lyon samples both pretreated and measured at Oxford have been assigned Oxford laboratory numbers in the usual way, in addition t…
Radiocarbon Dates From the Oxford Ams System
Shelter CaveThis human metacarpal was one of a collection of 34 human bones, all derived from a single adult skeleton, recovered in 1995 and 1996 from a stratified cave earth deposit in Shelter Cave-part of the Kitley Caves complex at Western Torrs Quarry, Yealmpton, Devon (NGR SX 57515123).The same stratigraphic layer produced undiagnostic flint flakes and a fragment of prehistoric pottery
Radiocarbon Dates From the Oxford Ams System
Radiocarbon Dates From the Oxford Ams System
Radiocarbon Dates From the Oxford Ams System
Refinement of graphite target production at Orau
Comment on ‘The Use of Bayesian Statistics for 14 C Dates of Chronologically Ordered Samples
The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.
Radiocarbon Dates From the Oxford Ams System
Presentation de la 29eme liste de dates au radiocarbone obtenues par spectrometrie de mass par le laboratoire d'Oxford. Le materiel date est constitue d'ossements humains et animaux ainsi que de coquilles et de charbons de bois mis au jour en Europe et au Perou
Radiocarbon Dates From the Oxford Ams System
Development of the Radiocarbon Calibration Program
This paper highlights some of the main developments to the radiocarbon calibration program, OxCal. In addition to many cosmetic changes, the latest version of OxCal uses some different algorithms for the treatment of multiple phases. The theoretical framework behind these is discussed and some model calculations demonstrated. Significant changes have also been made to the sampling algorithms used which improve the convergence of the Bayesian anal…
The Chemical and Enzymatic Hydrolysis of Archaeological Wood Cellulose and Monosaccharide Purification by High Ph Anion Exchange Chromatography for Compound-Specific Radiocarbon Dating
Preliminary experiments were carried out on archaeological wood to investigate methods of cellulose hydrolysis and carbohydrate monomer purification for the purpose of compound-specific radiocarbon dating. The Chelford log, a known 14 C dead source of wood cellulose, was selected for study in order to investigate the levels of contamination introduced during sample purification. Two methods of hydrolysis were examined, mineral acid hydrolysis and…
Wiggle Matching’ Radiocarbon Dates
This paper covers three different methods of matching radiocarbon dates to the ‘wiggles’ of the calibration curve in those situations where the age difference between the 14 C dates is known. These methods are most often applied to tree-ring sequences. The simplest approach is to use a classical Chi-squared fit of the 14 C data to the 14 C curve. This gives the calendar date where the data fit best and allows tests of how good the fit is. The onl…
Archaeology and ancient environmental studies (186 works) · Radiocarbon dating (161 works) · Archaeology (156 works) · Geography (133 works) · Geology (114 works) · Paleontology (80 works) · Pleistocene-Era Hominins and Archaeology (73 works) · History (69 works) · Geology and Paleoclimatology Research (57 works) · Chronology (48 works)