Prof Christopher Ramsey

Abstract:

The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available and updated data sets from 14C measurements on tree rings, plant macrofossils, speleothems, corals, and foraminifera. The calibration curves were derived from the data using the random walk model (RWM) used to generate IntCal09 and Marine09, which has been revised to account for additional uncertainties and error structures. The new curves were ratified at the 21st International Radiocarbon conference in July 2012 and are available as Supplemental Material at www.radiocarbon.org. The database can be accessed at http://intcal.qub.ac.uk/intcal13/. © 2013 by the Arizona Board of Regents on behalf of the University of Arizona.

Abstract:

The varved sediment profile of Lake Suigetsu, central Japan, offers an ideal opportunity from which to derive a terrestrial record of atmospheric radiocarbon across the entire range of the 14C dating method. Previous work by Kitagawa and van der Plicht (1998a,b, 2000) provided such a data set; however, problems with the varve-based age scale of their SG93 sediment core precluded the use of this data set for 14C calibration purposes. Lake Suigetsu was re-cored in summer 2006, with the retrieval of overlapping sediment cores from 4 parallel boreholes enabling complete recovery of the sediment profile for the present "Suigetsu Varves 2006" project (Nakagawa et al. 2012). Over 550 14C determinations have been obtained from terrestrial plant macrofossils picked from the latter SG06 composite sediment core, which, coupled with the core's independent varve chronology, provides the only non-reservoir-corrected 14C calibration data set across the 14C dating range. Here, physical matching of archive U-channel sediment from SG93 to the continuous SG06 sediment profile is presented. We show the excellent agreement between the respective projects' 14C data sets, allowing the integration of 243 14C determinations from the original SG93 project into a composite Lake Suigetsu 14C calibration data set comprising 808 individual 14C determinations, spanning the last 52,800 cal yr. © 2013 by the Arizona Board of Regents on behalf of the University of Arizona.

Abstract:

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 agree that the western part of the Carpathian basin served as the cradle of the LBK. The Balaton area and the region south of the lake had an important role in the development of the culture and in the spread of the Neolithic to central Europe. Southern Transdanubia, however, has previously been a veritable terra incognita for settlement research of the culture, despite the evidence for LBK sites from the region. Dating of the LBK occupation was funded by the OTKA project, Alsónyék from the beginning of food production to the end of the Neolithic and has been undertaken in a cooperation with the ERC-funded project, The Times of Their Lives. The aim has been to provide formally modelled date estimates of the timing and duration of the LBK occupation at Alsónyék, to gain insight into intra-site development and dynamics, and further the absolute chronology of the LBK on a regional scale. This paper presents 23 radiocarbon dates from 21 samples, interpreted within a formal chronological framework, for the LBK settlement at Alsónyék. The Bayesian model presented estimates that LBK activity probably began in 5335-5280 cal BC (68% probability), probably lasted for 290-410 years (68% probability), and probably ended in 5010-4915 cal BC (68% probability).

Abstract:

To the east of the main excavated area at Alsónyék, a small investigation took place which revealed a Sopot culture occupation, represented by pits, four ditches and 18 graves with the remains of 20 individuals. Some time-depth to the occupation is seen in the ditches cutting the pits, and some of the graves cutting the third ditch. The enclosed area was about five hectares, based on geomagnetic survey, but it is not possible to estimate the entire size of the occupation. The Sopot culture is normally regarded as a horizon with a questionable chronological position on the boundary between the Middle and Late Neolithic in western Hungary. Its role in the formation of the large-scale Lengyel complex remains controversial. Scholars can agree that it was brought to the region from the south, but there have been different views concerning the timing of its spread in the western Carpathian basin. Some have seen it as an entirely pre-Lengyel development, and others as at least partly contemporaneous with the early Lengyel culture. Dating within the ERC-funded project, The Times of Their Lives, aimed to provide formally modelled estimates of the timing and duration of the Sopot occupation at Alsónyék, and in so doing also to contribute to better understanding of the context and development of the Sopot culture in Hungary. The paper presents 17 dates on human and animal bone (including five existing dates from burials), which are modelled in a Bayesian statistical framework. The model concentrates on the samples available from the burials, and its main element regards the burials as representing a continuous period of activity in this area of the Alsónyék complex. The model estimates that the Sopot burials probably began in 5095-5020 cal BC (68% probability), probably lasted for 220-340 years (68% probability), and probably ended in 4825-4750 cal BC (68% probability). The model also estimates a terminus ante quem for the digging of Ditch 211 of probably 4930-4870 cal BC (68% probability). These estimates help to inform debate about the relative sequence of cultural developments in the region, and the relationship of Sopot communities to those of the LBK and the Lengyel cultures. As Alsónyék is the largest currently known Sopot burial ground in Hungary in eastern Transdanubia, this chronology is particularly valuable for modelling cultural interactions along the Danube between the northern Balkans and the Carpathian basin. The Sopot component also contributes significantly to the construction of a robust chronology for the long sequence of occupations at Alsónyék.

Abstract:

Imprecise chronology has entailed a fuzzy kind of prehistory. Prehistorians should no longer be content with timeframes that employ successive units of 200 years or more duration, or with slow change over the long term as their dominant chronological and interpretative perspective. The means to get away from very generalised accounts of the past is formal chronological modelling in a Bayesian framework. The Bayesian approach in general is outlined, with emphasis on its interpretive and iterative nature. The approach combines calibrated radiocarbon dates with knowledge of the archaeological contexts from which they are derived to produce a series of formal, probabilistic date estimates. Stringent demands are made of both the radiocarbon dates and our archaeological understanding of stratigraphy, associations, sample taphonomy and context in general. The Bayesian process at Alsónyék involved assessment of existing dates, careful definition of aims and objectives, the construction of a rigorous sampling strategy, with an explicit hierarchy of suitable samples, precise understanding of the contexts from which samples are derived, and simulation to achieve cost-effective use of resources. The principal material dated at Alsónyék was human and animal bone. Potential age offsets from non-vegetarian diets are carefully considered; 'perfect pairs' of human and animal bone samples from the same contexts indicate that human bone samples are not subject to wide-scale freshwater reservoir effects. Dietary inputs are estimated formally using a series of Bayesian mixing models. The sequence of iterative sampling submissions between 2012 and 2015 is described, and the procedures of the five laboratories involved are detailed. Procedures for model construction, validation and comparison are discussed. Finally, we consider how we can use precise timings to reveal the web of connections and successions that made up past lives, adding plot and context to a more precise chronicle to create narratives for peopling the past.