Peter Northover - Senior Research Fellow
Chris Salter - Research Fellow
Brian Gilmour - Academic Visitor
Meg Abraham - Research Student (DPhil)
Fay Horbury - Research Student (Part II)
Ann Colwin - Volunteer Assistant
Index
(1) Non-ferrous and precious metallurgy in the European Iron Age
Dr J.P. Northover, M. Schindler*, C. Zingerle**
The study of copper-based and precious metal alloys from excavations
and hoards of the pre-Roman Iron Age is leading for the first time to an
understanding how these metals were made and traded in a period when iron
had become the dominant utilitarian metal. Material is now available to
illustrate how production on individual sites was organized and what techniques
were used together. Attention is also focussed on cemeteries to look for
associations between gender and status of individuals and the technical
quality of artefacts buried with them. (*Abteilung Ur-und Frügeschichte,
Universität Zürich, Switzerland; **Institut für Ur-und Frühgeschichte,
Universität Wien, Austria)
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Dr J.P. Northover, Dr D.M. Metcalf*, Dr C.E. King*, Dr L. Treadwell*
The Cameca SEMPROBE is used to study the copper-, silver- and gold-based
alloys used for a variety of coinages. Current projects involve Roman base-silver
coinages of the later 3rd century AD, the silver and base-metal coinages
of medieval England, the coinage of the pre-Roman Iron Age, Indo-Greek
and Islamic coinages. Very large databases of analyses have been and are
being assembled in all these areas and attention is now directed to new
methods for interrogating these. (*Ashmolean Museum,
Oxford)
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Dr J.P. Northover, Dr K. Pragg*, Dr G. Philip**
Microanalysis and metallography have been used to characterize the metalwork
from a number of major excavations in the upper Euphrates basin. The sites
straddle political and economics boundaries of the 3rd millennium
B.C. during the period which bronze became the main utilitarian metal.
The results have given us a new understanding of the way in which bronze
became part of the metal economy and have also focussed our attention on
the great importance of recycling in these early cities. (*
University of Manchester, ** Department of Archaeology,
University of Durham)
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C. J. Salter; Dr. B. J. J. Gi1mour
A study of the changes in slag inclusion and metal compositions that
occur during the forge welding of iron. In particular
those changes seen in phosphoritic/non-phosphoritic composite
iron artefacts. (In collaboration with The Royal Armouries, Leeds)
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Dr J. P. Northover
The effects of high temperatures on copper alloys in oxidizing, neutral
and reducing atmospheres are being studied by optical metallography and
by experimental replication. The results are used to determine the placement
of grave goods in cremation pyres to assist in interpreting the burial
rites. (In collaboration with Wessex Archeology)
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Dr. J.P. Northover, J. Hirx*
The discontinuous precipitation of copper at grain boundaries from supersaturated
solution at room temperature in wrought and annealed silver alloys with
2-10% copper has been advanced as an indicator of age. This project will
make the first transmission electron microscopy studies of the morphology
and structure of the precipitates, determine the length, if any, of an
incubation period, and find the conditions under which precipitation changes
from discontinuous to continuous. The possibility of accelerating the discontinuous
precipitation by annealing at intermediate temperatures will be explored.
(*Conservation Section, Los Angelas County Museum of Art)
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Dr J.P. Northover, Dr G.W. Grime, M.H. Abraham
The requirements of museum collections have stimulated this project
in non-destructive and minimally destructive analysis of ancient Egyptian
bronze. The aim is to use a laser to mill sub-millimetre diameter windows
in the patina on selected bronzes and then use the SPM to analyse the metal
as it is exposed, with the X-ray mapping facility employed to make basic
metallographic observations. An experimental programme will develop the
best mode of operation and assess the quality of the analyses in comparison
with sample-based analysis.
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C.J.Salter, Dr. J. P. Northover., S. Jones*
Although there is extensive evidence of Bronze Age mining activity in
Britain, as yet no evidence of prehistoric copper smelting has been discovered
on the British mainland. A small quantity of slag-like from contexts dated
to cfrca 1580 BC are being studied to determine its nature and mode of
origin. This will include experimental reproduction.
(*Gwynedd Archaeological Trust)
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C.J.Salter, P. Crew*
A series of iron smelting an smithing experiments have been carried
out to reproduce the metal and other iron
working debris from these important Iron Age sites. Presently, this
material is being studied, an attempt to
fully understand the chemistry, microstructure
and mechanical properties of the different types of iron and
steel produced. (*Snowdonia National Park Study Centre, Meantwrog,
Gwynedd )
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Dr. J. P. Northover, N. Norman*, M. Sahlstedt**
A combination of optical and scanning electron microscopy, electron
microprobe analysis and PIXE/RBS spectrometry will be used
to compare the effects of different conservation methods of a group of
Bronze Age tools and weapons. Particular aftention will be paid to the
preservation of surface detail during a cleaning and treatment, and
to the distribution of inhibiting species in the corrosion and patina after
treatment.(*Department of Antiquities, Ashmolean Museum; **Conservation
Institute, Gothenburg University)
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C.J. Salter, G. Hey*, B.J.J. Gilmour, K. Penn***, T. Mallin**
A systematic survey of the ferrous artefacts from a number of East Anglian
and Midland sites is being carried out to determine range and distribution
of various Anglo-Saxon black-smithing skills and technologies. (*Oxford
Archaeological Unit;***Norfolk Archaeological Unit, **Cambridgeshire Archaeology)
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Dr. J. P. Northover, F. Horbury, D. Wrjght*
The collections of the National Railway Museum will be utilised to study
the development of materials for rails. The collection extends from cast
iron tramplates at the end of the 18th century through wrought iron to
early Bessemer steel to eutectoid and alloy steels. Metallography and microanalysis
will be used to characterise the irons and steels and the results will
be compared with the documentary history of the subject. The project is
designed in particular to examine the impact of steel and understand
the problems associated with its introduction in railway use. (*National
Railway Museum, York)
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A. Colwin, C.J. Salter, The Archaeology Committee of the Historical Metallurgy Society
A database of as many iron working sites dating to before 1600 is being built up. At present it contains over 1900 sites. It hoped that this database will prove useful for archaeologist studying the production, and use of iron and its alloys. It already has shown that the field data is very much biassed by the location of the field-workers.
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