102 research outputs found
Calibration of the Radiocarbon Time Scale for the Southern Hemisphere: AD 1850-950
No full textWe have conducted a series of radiocarbon measurements on decadal samples of dendrochronologically dated wood from both hemispheres, spanning 1000 years (McCormac et al. 1998; Hogg et al. this issue). Using the data presented in Hogg et al., we show that during the period AD 950-1850 the 14C offset between the hemispheres is not constant, but varies periodically (~130 yr periodicity) with amplitudes varying between 1 and 10‰ (i.e. 8-80 yr), with a consequent effect on the 14C calibration of material from the Southern Hemisphere. A large increase in the offset occurs between AD 1245 and 1355. In this paper, we present a Southern Hemisphere high-precision calibration data set (SHCal02) that comprises measurements from New Zealand, Chile, and South Africa. This data, and a new value of 41 ± 14 yr for correction of the IntCal98 data for the period outside the range given here, is proposed for use in calibrating Southern Hemisphere 14C dates
Extended Radiocarbon Calibration in the Anglo-Saxon Period, AD395-485 and AD735-805
No full textRadiocarbon dating has been used infrequently as a chronological tool for research in Anglo-Saxon archaeology. Primarily, this is because the uncertainty of calibrated dates provides little advantage over traditional archaeological dating in this period. Recent advances in Bayesian methodology in conjunction with high-precision 14C dating have, however, created the possibility of both testing and refining the established Anglo-Saxon chronologies based on typology of artifacts. The calibration process within such a confined age range, however, relies heavily on the structural accuracy of the calibration curve. We have previously reported decadal measurements on a section of the Irish oak chronology for the period AD 495–725 (McCormac et al. 2004). In this paper, we present decadal measurements for the periods AD 395–485 and AD 735–805,which extends the original calibration set
'Insularity is not the way forward': three university vice-chancellors on Brexit
No full textFirst paragraph: Universities and their leaders are contemplating the spectre of a British exit from the European Union with considerable alarm. Over the last few decades, the institutional architecture of Britain’s universities has become ever more European. The threat of Brexit jeopardises a range of collaborations and research projects including the European Union’s Horizon 2020 programme and the ERASMUS student exchange scheme. Universities, unsurprisingly, are worried. Access article on The Conversation website: https://theconversation.com/insularity-is-not-the-way-forward-three-university-vice-chancellors-on-brexit-6066
High-precision radiocarbon measurements of contemporaneous tree-ring wood from the British Isles and New Zealand: AD 1850-950.
No full textThe University of Waikato, Hamilton, New Zealand and The Queen's University of Belfast, Northern Ireland radiocarbon dating laboratories have undertaken a series of high-precision measurements on decadal samples of dendrochronologically dated oak (Quercus petraea) from Great Britain and cedar (Libocedrus bidwillii) and silver pine (Lagarostrobos colensoi) from New Zealand. The results show an average hemispheric offset over the 900 yr of measurement of 40±13 yr. This value is not constant but varies with a periodicity of about 130 yr. The Northern Hemisphere measurements confirm the validity of the Pearson et al. (1986) calibration dataset
ShCal04 Southern Hemisphere Calibration, 0–11.0 Cal Kyr BP
No full textRecent measurements on dendrochronologically-dated wood from the Southern Hemisphere have shown that there are differences between the structural form of the radiocarbon calibration curves from each hemisphere. Thus, it is desirable, when possible, to use calibration data obtained from secure dendrochronologically-dated wood from the corresponding hemisphere. In this paper, we outline the recent work and point the reader to the internationally recommended data set that should be used for future calibration of Southern Hemisphere 14C dates
An illustrated guide to measuring radiocarbon from archaeological samples
No full textRadiocarbon dating has been central to the construction of archaeological chronologies for over 50 years. The archaeological, scientific and (increasingly) statistical methods for interpreting radiocarbon measurements to produce these chronologies have become ever more sophisticated. The accurate measurement of the radiocarbon content of an archaeological sample is, and always has been, fundamental to any interpretation. This article provides an overview of the different approaches adopted for measuring radiocarbon from archaeological samples by laboratories at the start of the 21st century.
New Scientific Dating of the Later Bronze Age Wells at Swalecliffe, Kent
No full textThe Swalecliffe later Bronze Age well complex was reported in detail in volume 83 of the Antiquaries Journal. The site comprised seventeen wells cut into the base of a previously reduced hollow. Groundwater could thus have been more readily accessed within the subsequently cut well pits. The depth of the base of the wells, at up to 2.5m below ground level, and their consequent waterlogged nature, allowed exceptional preservation of wooden linings and plank steps. Application of dendrochronological and radiocarbon dating suggested that the individual wells were used in sequence over a period of around 500 years, from an origin probably in the late thirteenth century BC to abandonment probably within the seventh century BC. The earlier phases (1–4) were dated mainly by dendrochronology, a 348-year sequence known as SWALECLF 1, whilst the later phases (5–7) were dated by a series of five radiocarbon dates.</jats:p
Preventing and Responding to Bullying: An Elementary School's 4-Year Journey
No full text Bullying continues to be a pervasive problem in schools and requires a schoolwide approach. This article describes the action research process used to examine the impact of a 4-year, K-5 school bullying prevention and intervention. The school counselors collaborated with students, staff, and parents to implement the program, and collected and analyzed data to improve the program. Results indicated that the program reduced bullying and increased students’ perception that adults listen to bullying reports. The author offers suggestions for improving bullying interventions. </jats:p
Marine radiocarbon reservoir corrections for the Mediterranean and Aegean Sea.
No full textRadiocarbon measurements of nine known age shells from the Mediterranean and the Aegean Seas combined with previous measurements provide an updated value for Delta-R, the local variation in the reservior correction for marine samples. Comparison of pre-1950s samples from the Algerian coast, with one collected in 1954, indicates early incorporations of nuclear weapons testing 14C into the shallow surface waters of the Mediterranean. Comparisons between different basins indicate the surface waters of the Mediterranean are relatively homogenous. The recommended Delta-R for calibration of the Mediterranean marine samples with the 1998 marine calibration dataset is 58 +/85 14C yr, but variations in the resevoir age beyond 6000 cal BP should be considered.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202
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