Microchemical characterisation of natural gold and artefact gold as a tool for provenancing prehistoric gold artefacts: A case study in Ireland R.J. Chapman a, * , R.C. Leake a , R.A. Warner b , M.C. Cahill c , N.R. Moles d , C.A. Shell e , J.J. Taylor f a School of Earth Sciences, The University, Leeds LS2 9JT, United Kingdom b Department Archaeology and Ethnography, Ulster Museum, Botanical Gardens, Belfast BT9 5AB, United Kingdom c Irish Antiquities Division, National Museum of Ireland, Kildare St., Dublin 2, Ireland d School of the Environment, University of Brighton, Cockcroft Building, Lewes Road, Brighton BN2 4GJ, United Kingdom e Department Archaeology, University of Cambridge, Downing St., Cambridge CB2 3DZ, United Kingdom f Department Archaeology, Classics, and Egyptology, University of Liverpool, L69 3BX, United Kingdom Received 20 December 2004; accepted 27 January 2006 Editorial handling by R. Fuge Abstract The importance of Au to ancient societies has encouraged many archaeologists to search for the sources exploited in antiquity. These projects generally involve detailed studies of artefacts and comparison of their chemical characteristics with those reported for natural Au. However, descriptions of natural Au are frequently inadequate for provenancing stud- ies, and the compositional variability of the material is not widely recognised. The present study describes a new approach to gold provenancing using the technique of microchemical characterisation in which populations of gold grains are clas- sified according to the alloy compositions and the assemblages of microinclusions of other minerals. This technique, orig- inally developed to identify sources of alluvial gold during Au exploration, has proved applicable to provenancing studies in four main areas. Firstly, microchemical characterisation of artefacts grouped according to archaeological criteria can indicate the number of sources exploited in relation to time and artefact taxonomy. Secondly, knowledge of the total var- iation in chemical characteristics of natural Au from a particular region provides an excellent database for provenancing and reduces the need for exhaustive sampling. Thirdly, it is possible to predict how Au alloys were modified during fab- rication as a consequence of assimilation of mineral inclusions. Finally, identification of inclusion phases in artefact Au can provide information on metallurgical practices. These principles have been applied to the search for the source of Au used for the unique traditions of prehistoric Irish metalworking. Studies of 180 Irish Au artefacts belonging to four major metalworking traditions dating from the Early Bronze Age (2400 BC) to the Iron Age, (150 BC) show that each group exhibits distinctive Ag and Cu contents. Parallel stud- ies of 2267 natural Au grains from 58 alluvial localities and four bedrock localities throughout Ireland reveal a broad pattern of alloy compositions consistent with style of mineralisation and host geology. The ranges of Ag contents of Early Bronze Age and Middle Bronze Age artefacts suggests that the Au source lies within Lower Palaeozoic sedimentary rocks of the 0883-2927/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeochem.2006.01.007 * Corresponding author. Fax: +44 0113 343 5259. E-mail address: R.Chapman@earth.leeds.ac.uk (R.J. Chapman). Applied Geochemistry xxx (2006) xxx–xxx www.elsevier.com/locate/apgeochem Applied Geochemistry ARTICLE IN PRESS