COMPOSITIONAL CHARACTERIZATION OF FRENCH LIMESTONE: A NEW TOOL FOR ART HISTORIANS*

Limestone from quarries known to medieval craftsmen and from the monuments they built and embellished, as well as from carvings now in museum collections, has been characterized by neutron activation analysis. Specimens from 38 quarries in the Lutetian and Jurassic limestone formations of France and from sculptures in American and French museums have been tested, and the results have been compiled in a data base to which art historians may refer when attempting to determine provenance for sculptures. Multivariate statistical analysis of concentration data shows stone from a particular quarry in the Paris basin to be compositionally homogeneous and distinguishable from other quarries in the same formation. The same approach to data related to quarries near the Burgundian abbey of Cluny finds general agreement between classifications based on compositional and on petrographic data, but the number of samples available for analysis at the time of writing was insufficient to achieve the finer distinctions reported for the Paris basin.     

A PILOT STUDY IN NON-CONTACT LASER PHOTOTHERMAL ARCHAEOMETRY OF ANCIENT STATUARY PEDESTAL STONES FROM CYPRUS

Several samples of geological stones from statuary pedestals found in various archaeological sites in Cyprus have been characterized using non-contact laser infrared photothermal radiometry. Thermal diffusivities and effective optical absorption coefficients were calculated using a one-dimensional thermal-wave model. The mean values and standard deviations were tabulated and comparisons were made with lithographic and petrographic studies of the samples. Good correlations were found, thus demonstrating that laser photothermal archaeometry is a promising methodology for the accurate, potentially non-destructive and convenient characterization of the origins of ancient stones in Cyprus and other geological and archaeological sites.     

A GEOARCHAEOLOGICAL STUDY OF THE ANCIENT QUARRIES OF SIDI GHEDAMSY ISLAND (MONASTIR,TUNISIA)

Amongst a large number of ancient quarries scattered along the North African coast, those at Sidi Ghedamsy (Monastir, Tunisia) have supplied building stones of Pliocene age. Two lithofacies have been distinguished in the quarry faces: (i) fine sandy limestone, which has been used in the construction of Roman and Arabic monuments; and (ii) porous and coarse limy sandstone, which is of bad quality for construction. Laboratory analysis results confirm that the exploitation of stone in antiquity was well focused on the levels containing the first type. This is confirmed by geotechnical tests, which show that the fine sandy limestone is harder and less porous than the coarse limy sandstone. Extraction of these stones began in the Roman period. The Romans exploited the quarries using steel tools that permitted the extraction of blocks from several levels. In the eighth century, Arabic quarry workers continued the stone extraction using the same technique, but they produced blocks of small and medium size. Statistical measurements have been done on the quarry faces and on the walls of the Ribat in order to understand the degree of conformity between the dimensions of the extracted blocks and those used for building, and ultimately to attempt to date the quarries and the construction of the Ribat.     

CHARACTERIZATION AND PROVENANCE OF LIME PLASTERS FROM THE TEMPLO MAYOR OF TENOCHTITLAN (MEXICO CITY)

In this work, we present the results of the analyses of 20 lime plaster samples taken from the Templo Mayor (Great Temple), the main pyramid of Tenochtitlan (Mexico), the ancient capital of the Mexicas. The samples were analysed to recover information on the mixtures used in the fabrication of the plasters and for the provenance of the raw materials (in particular, limestone) used to make the plasters. The characterization of the samples was done by OM, SEM/EDS, XRF and LA–ICP–MS analyses, while the identification of the provenance of raw materials was done by studying the lumps present in the samples with LA–ICP–MS. The objective of the study was to establish if there was a relationship between changes in the construction techniques employed in the pyramid over time and if there were changes in the provenance of the raw materials. Six different construction phases of this pyramid are analysed, showing the similarities and differences among them, mainly based on differences in the sieving of the aggregates and in the raw materials employed. The provenance studies of the limestone used to make the plasters demonstrated that all the limestone comes from the Tula region.     

THE HISTORY OF THE BROOKHAVEN NATIONAL LABORATORY PROJECT IN ARCHAEOLOGICAL CHEMISTRY,AND APPLYING NUCLEAR METHODS TO THE FINE ARTS

This paper traces the events leading up to the formation of a project in 1954, in the Chemistry Department at Brookhaven National Laboratory, dedicated to the application of those new developments that were rapidly transforming postwar nuclear science to the parallel humanistic disciplines of archaeology and the fine arts. The further evolution of this effort involved the enlightened support of the Department of Energy (then AEC and ERDA) coupled with the lively interests of the archaeological, fine‐arts and art‐historical communities, their professional academics and the many graduate and undergraduate students who participated in the Brookhaven project. But more than new scientific methodologies, concepts and instrumentation were deployed. What developed was a large‐scale, truly interdisciplinary effort, where scholars of the humanities and sciences worked side by side in a remarkable way, each led by the other, to the mutual benefit and increase of their knowledge and understanding. A paradigm of co‐operation between arts and sciences was initiated: this paper presents a record of the process and its outcome, a novel blending of science and humanism that is very much taken for granted by research workers today.     

AN ANALYTICAL STUDY OF IBERIAN IRON AGE STONE SCULPTURES AND THEIR SURFACE MARKS

The Archaeological Museum of Jaén's sizeable collection of Iron Age sculptures, dating from the fifth century bce , were all found at Cerrillo Blanco de Porcuna, a site in the Spanish province of Jaén. The collection comprises over 40 statues and hundreds of fragments. Incisions recently identified on some of these sculptures have been interpreted as sculptors' marks. The present archaeometric study, conducted with a 3D roughness meter, showed that the marks on several of the sculptures analysed were made with the same type of tool and the same engraving technique. While the graphological differences denote different authorship, they would appear to have been made in the same workshop. The morphological differences observed in the lines analysed on other sculptures are interpreted to indicate the use of other types of tools and engraving techniques.     

MAGNETIZATION DATING AT A MEDIEVAL MONASTERY (TUPHOLME,LINCOLNSHIRE)*

Tupholme Abbey, founded by c. 1166, was constructed of limestone masonry, some of which was reoriented at several times through its history. The limestone progressively acquired a ‘soft’, time-dependent magnetization in the earth's magnetic field—viscous remanent mag-netization (VRM)—that acts like a clock. Although VRM is normally disregarded by geologists because of its ephemeral nature, this remanence is acquired and persists over time-scales that are useful to archaeologists. Successive VRMs were initiated, at different ages of stabilization of the masonry, thus yielding a chronometric curve that allows us to determine, at least relatively, when masonry was installed.     

MICROCHEMICAL CHARACTERIZATION OF BUILDING STONE FROM SEVILLE CATHEDRAL,SPAIN

Enrichment diagrams for trace elements have been proposed as a useful and straightforward procedure to identify ores and stones. The identification of the diverse stone of the exterior of the Cathedral of Seville has been achieved by this means. Fourteen trace elements have been analysed, from both quarry and building material samples, using atomic absorption and flame emission spectrometry in order to apply enrichment diagrams for identification purposes.     

ANCIENT EGYPTIAN LIMESTONE QUARRIES: A PETROLOGICAL SURVEY*

Ancient Egyptian limestone quarries in the Nile Valley occur in six geological formations of Palaeogene age. Samples were collected from 23 of the 48 known quarries, and analysed by thin-section petrography and X-ray fluorescence spectrometry. Results of the analyses show that the geological formations can be identified from rock texture and allochem types, and a plot of SiO₂/Al₂O₃ versus CaO/[CaO + MgO]. The application of these petrographic and geochemical parameters make it possible to determine the geographic provenance of limestone used in ancient Egyptian sculptures and monuments.     

A MULTIDISCIPLINARY APPROACH TO THE CHARACTERIZATION OF ROMAN GRAVESTONES FROM AQUILEIA (UDINE,ITALY)*

The results of an archaeometric study on gravestone production in Aquileia (northeastern Italy) during Roman Republican times are reported here. The artefacts are made of limestone, quarried from the sedimentary sequence of the Trieste Karst (Carnican Alps, northeastern Italy), as testified by historical sources which refer to the ‘Roman Quarry’ at Aurisina. The rock types used for the gravestones are petrographically, geochemically and geochronologically homogeneous, and display similar faunal assemblages. In addition, their age is restricted to the Santonian – Lower Campanian. Comparisons between archaeological finds and rock specimens from various active and inactive quarries in this area suggest that quarrying during Roman Republican times was limited to a specific stratigraphic horizon of the sedimentary sequence, corresponding to the higher part of the ‘Roman Quarry’.