Radiocarbon Dates 1981-1988
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RADIOCARBON DATES RADIOCARBON DATES RADIOCARBON DATES This volume holds a datelist of 1285 radiocarbon determinations carried out between RADIOCARBON DATES 1981 and 1988 on behalf of the Ancient Monuments Laboratory of English Heritage. It contains supporting information about the samples and the sites producing them, a comprehensive bibliography, and two indexes for reference and analysis. An introduction provides discussion of the character and taphonomy of the dated samples from samples funded by English Heritage and information about the methods used for the analyses reported and their calibration. between 1981 and 1988 The datelist has been collated from information provided by the submitters of the samples and the dating laboratories. Many of the sites and projects from which dates have been obtained are published, although, when many of these measurements were produced, high-precision calibration was not possible. At this time, there was also only a limited range of statistical techniques available for the analysis of radiocarbon dates. Methodological developments since these measurements were made may allow revised archaeological interpretations to be constructed on the basis of these dates, and so the purpose of this volume is to provide easy access to the raw scientific and contextual data which may be used in further research. Alex Bayliss, Robert Hedges, Robert Otlet, Roy Switsur, and Jill Walker andJill Switsur, Roy Robert Robert Otlet, Hedges, Alex Bayliss, Front cover: Excavations at Avebury Henge, 1908 (© English Heritage. NMR) Back cover: Curly Humphries. Benzene synthesis from carbon dioxide at AERE Harwell (© NDA, reproduced with permission from the NDA) Product Code: 51762 ISBN: 978-1-84802-130-3 Alex Bayliss, Robert Hedges, Robert Otlet, Roy Switsur, and Jill Walker RADIOCARBON DATES from samples funded by English Heritage between 1981 and 1988 RADIOCARBON DATES from samples funded by English Heritage between 1981 and 1988 Alex Bayliss, Robert Hedges, Robert Otlet, Roy Switsur, and Jill Walker Published by English Heritage, The Engine House, Fire Fly Avenue, Swindon SN2 2EH www.english-heritage.org.uk English Heritage is the Government’s statutory adviser on all aspects of the historic environment. © English Heritage 2012 All images, unless otherwise specified, are either © English Heritage or © Crown copyright.NMR. The negative numbers for English Heritage and NMR images are noted in square brackets in the captions where possible. First published 2012 10 9 8 7 6 5 4 3 2 1 ISBN 978-1-84802-130-3 Product Code 51762 British Library Cataloguing in Publication Data A CIP catalogue record for this book is available from the British Library. All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage or retrieval system, without permission in writing from the publisher. Application for the reproduction of images should be made to the National Monuments Record. Every effort has been made to trace the copyright holders and we apologise in advance for any unintentional omissions, which we would be pleased to correct in any subsequent edition of this book. The National Monuments Record is the public archive of English Heritage. For more information, contact NMR Enquiry and Research Services, National Monuments Record, The Engine House, Fire Fly Avenue, Swindon SN2 2EH; telephone (01793) 414600. Edited and brought to publication by David M Jones, Publishing, English Heritage, The Engine House, Fire Fly Avenue, Swindon SN2 2EH. Cover design and page layout by www.farrbott.com Indexed by Alan Rutter Printed by 4Edge Ltd, Hockley. www.4edge.co.uk Contents Radiocarbon Dates funded by English Heritage between 1981 and 1988 by Alex Bayliss . vii Introduction . vii History of this volume. viii Sample selection and characterisation . xi Laboratory methods . xiv Fractionation and radiocarbon ages . xvi Calibration . xvii Quality assurance. xix Statistical modelling. xxii Using the datelist . xxiv Acknowledgements . xxiv Charcoal and wood identification of samples dated before 1981 by Rowena Gale . xxvi Datelist . 1 Bibliography . 325 Index of laboratory codes . 344 General index. 363 v vi Radiocarbon Dates funded by English Heritage between 1981 and 1988 Introduction Only samples from sites in which English Heritage had a formal interest were eligible for dating through the Ancient This volume presents a detailed catalogue of the radiocarbon Monuments Laboratory. Often samples came from dates funded by English Heritage between April 1981 and archaeological excavations funded, wholly or in part, by March 1988. A few results from samples submitted before April English Heritage. Some samples were from sites excavated by 1981, which were not published by Jordan et al (1994), are also the in-house archaeological team or on sites in guardianship, included. In total details of 1285 determinations are provided. but most were from excavations undertaken by others in advance of development. This volume covers a period 14 Number of C determinations before the wide-scale availability of archaeological funding 0 50 100 150 200 250 from developers, which followed the adoption of new planning guidance in the early 1990s (PPG16 1990). 1961 Other samples were submitted from archaeological research 1962 programmes undertaken by the staff of the Ancient Monuments Laboratory and their university-based 1963 contractors. For example, a number of dates were funded to 1964 aid the development of oak master chronologies for dendrochronology in England, often in connection with early 1965 attempts to provide tree-ring dates for timberwork in buildings under repair. 1966 The 1970s and 1980s saw the expansion of ‘rescue’ 1967 archaeology undertaken in advance of construction projects (Rahtz 1974). This expansion is mirrored in the number of 1968 samples submitted for dating by English Heritage and its 1969 predecessors1 (Fig 1). The establishment of the radiocarbon dating laboratory at AERE Harwell in the early 1970s 1970 allowed larger numbers of samples to be processed using liquid Year of measurement Year 1971 scintillation counting, but, despite stringent vetting arrangements, samples appropriate for dating always exceeded capacity. 1972 The major limitation of conventional radiocarbon dating 1973 is the sample size that is necessary to provide a statistically viable number of decay counts for age calculation. Typically 1974 300g of bone, 200g of peat, or 15g of charcoal was required. 1975 This had an inevitable effect on the number and nature of the samples that could be selected for dating (see below). 1976 It also meant that when the Harwell laboratory constructed 1977 a miniature gas-proportional counter, which could date 1978 OxA-OA 1979 1980 Q- 1981 1982 1983 1984 1985 1986 HAR-HAAR- 1987 1988 Fig 2. Proportion of radiocarbon measurements included in this Fig 1. Radiocarbon measurements from English sites funded by volume processed by each collaborating facility (HAR-, AERE English Heritage, the Department of the Environment, the Ministry Harwell; Q-, The Godwin Laboratory, University of Cambridge; of Public Buildings & Works, and the Ministry of Works (1961–88). OxA-, Oxford Radiocarbon Accelerator Unit). vii Introduction LSCLSSC History of this volume (high-precision)(h h ) AMS The compilation of this volume began in 1994. From April 1985, the Harwell Laboratory produced a GPGPCPC series of datelists in the journal Radiocarbon detailing measurements made under its contract with English Heritage (Walker and Otlet 1988; Walker et al 1988; 1990; 1991a–b; Hardiman et al 1992). The great majority of samples dated during this period appear in these datelists, although samples dated between April 1981 and March 1985 were only published in this way erratically. Although this initiative was highly laudable, especially in LSC the promptness of publication, it was limited in a number of ways. First, the space restrictions imposed by journal publication meant that only very brief details of sample character and provenance could be provided, even though much fuller information had often been provided by Fig 3. Techniques of radiocarbon dating used for the archaeologists on the submission of the sample. Second, the measurements reported in this volume (LSC, liquid scintillation published radiocarbon ages were not calibrated. Third, most counting; GPC, gas-proportional counting; AMS, accelerator mass of the projects from which results were reported were still on- spectrometry). going at the time of publication, and so archaeological interpretation of the dates could not be provided with the benefit of post-excavation analysis. much smaller samples (typically 10g of bone, 6g of peat, For these reasons, in 1994 it was decided to include fuller or 1g of charcoal), it was in great demand. This facility was details of radiocarbon dates that had already appeared in initially established in 1981, but development took rather summary form in the Harwell datelists in Radiocarbon in longer than expected and, by the time the small-sample future volumes of Radiocarbon Dates. counter became fully operational, there was a long queue This decision was reinforced in 1995 when the Ancient of samples. Monuments Laboratory retrieved both the paper archive and In 1983 this need to date a wider range of smaller samples the remaining physical samples from Harwell on the was further met by the dating by the Oxford Radiocarbon demolition