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A Sample Analysis of British Middle and Late Bronze Age Material, using Optical Spectrometry

Published online by Cambridge University Press:  27 May 2014

M. A. Brown
Affiliation:
Research Laboratory for Archaeology and the History of Art, Oxford
A. E. Blin-Stoyle
Affiliation:
Research Laboratory for Archaeology and the History of Art, Oxford

Extract

Metallurgical analysis of prehistoric material has hitherto been concentrated on examination of early artifacts, presumably made from newly-won metal, which may therefore contain trace elements to indicate the sources and trade-routes of contemporary metal supply. The present study was undertaken to discover whether bronze artifacts from the British Middle and Late Bronze Age, when an important component of the bronzes produced must have been re-used metal, show nonetheless perceptible variations in metal composition, which might correlate with changes of bronze types, or with the successive industries of the archaeological sequence.

Analyses were made at the Research Laboratory for Archaeology in the University of Oxford, using an optical emission spectrometer. Samples of the bronzes studied were examined for the elements copper (Cu), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), nickel (Ni), bismuth (Bi), iron (Fe), zinc (Zn), silver (Ag), gold (Au) and magnesium (Mg), the only elements found in the bronzes in appreciable quantities.

Type
Research Article
Copyright
Copyright © The Prehistoric Society 1959

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References

page 188 note 1 The spectrometric analyses of the 438 bronzes can be found published in full in a special supplement of Archaeometry, vol. 2 (the Bulletin of the Archaeological Research Laboratory, OxfordGoogle Scholar).

page 189 note 1 It is noteworthy that palstaves from a French hoard (Bernay, near Abbeville), closely similar to the low-flanged South British type, also fell within the limits of this group (nos. 57–9, 63–9), as did also a rapier from R. Seine (9).

page 189 note 2 The preliminary work in setting up the apparatus and refining the method as well as much of the laborious calculation involved in making the analyses was done by R. V. Jolowicz with the assistance of C. C. Humphreys under the personal supervision of the Director of the Laboratory, Dr E. T. Hall.

page 189 note 3 The Hilger spectrograph was presented to the Laboratory by Major H. W. Hall.

page 190 note 1 Gold was rarely detected in the sample, while zinc frequently was either absent, or fell below the detectable limits (0.04%), as did magnesium (0.005%).

page 190 note 2 Thus, in the simplified presentation on fig. 1a, 5% of the sample contained 6.2% or less of tin, 10% had 7% or less, 50%, 11% or less, and 90%, 17% or less.

page 193 note 1 See Metallurgy by Gregory, E. (Blackie, 1932), p. 232Google Scholar and Metals by Carpenter, H. and Robertson, J. M. (1939), p. 1320Google Scholar.

page 196 note 1 See the preceding paper in the present volume, pp. 144–187 above. M.B.A. hoards sampled are: Leopold Street, Burgesses' Meadow, Barton Bendish, Ilminster, Maentwrog, Hollingbury, Stibbard, Burnham-on-Crouch, East Dean, Blandford, Billinghurst, Grunty Fen, Downham Fen, Werrar, Monkswood, Edington Burtle, Sherford, Taunton Workhouse. From among them only three bronzes contained > 1% lead: a ribbed bracelet (342), socketed hammer (17), and a unique bevelled ring (471), which moreover contains 7·5% of zinc—a phenomenon at present unexplained.

page 196 note 2 See PPS, VII, pp. 128131Google Scholar.

page 196 note 3 Use of lead is likewise absent from forms among late Middle Bronze material arriving or copied from abroad, notably the North-west German early square-mouthed and narrow socketed axes (schlichtes Vierecktüllenbeil—13, 83, 166) and the Ilmenau decorated and ribbed bracelets from Ramsgate (466–67) omitted from the sample as probable imports.

page 197 note 1 In the Late Bronze Nettleham hoard the spearhead (206), perforated at the base of the wings to simulate a Middle Bronze Age basal-looped spearhead, is the sole bronze containing < 1% lead.

page 197 note 2 SirEvans's, JohnAncient Bronze Implements mentions comparable analyses (p. 423)Google Scholar.

page 198 note 1 IIa—112–24, 148–49, 222–3, 253, 257–80; IIb—34–6, 44, 130, 135, 139, 143, 152–3, 194, 282, 290, 336, 361–2, 385, 391, 398.

page 199 note 1 See p. 184 of preceding paper.

page 199 note 2 A wing-decorated socketed axe from Leigh-on-Sea (380) also contains more than 0·9% arsenic.