Geochemical and Magnetic Provenancing of Roman Granite Columns from Andalucía and Extremadura, Spain

One hundred and fifty two granite columns were examined in eight towns and archaeological sites in Andalucía and Extremadura, Spain, in order to determine the geological provenance of the columns. Three non-destructive methods of characterization were used: mineralogical features, magnetic susceptibility, and concentrations of radioelements (K, U, Th) determined by portable gamma ray spectrometry. Columns were compared with potential sources within Spain and in the Mediterranean area using analogous data previously published and also new data obtained for this work. The majority of the columns are made of Spanish granites, some of which were probably quarried near Mérida. Different chemical types of Spanish granites were used in the northern part of the area studied (Extremadura) and in the southern part (Andalucía). Twenty five columns are not of Spanish granites, but were imported from other sources, namely the Troad and Kozak Dağ areas of western Turkey, the Italian islands of Elba and/or Giglio, and Sardinia (confirming a column previously identified in the literature). The imported columns are found in Itálica, Hispalis (Seville) and Astigi (Écija), and were probably carried along the River Guadalquivir and its tributaries.     

Black limestones used in antiquity: the petrographic,isotopic and EPR database for provenance determination

We compiled a database of some of the most important black limestone quarries used in Roman times to be able to determine the provenance of ancient artifacts. For this purpose, we adopted a multimethod approach using the techniques commonly applied to study the provenance of white marbles: petrographic observations, carbon and oxygen isotope composition, electron paramagnetic resonance (EPR) spectra characteristics. Few black limestones were quarried and traded in ancient times; indeed, the importance of most of these quarries was restricted to the areas in which they were located. In this work, we selected a limited number of quarries that produced material believed to have been exported and used throughout the Mediterranean area; most of the quarries selected are found in northern Tunisia, i.e. the Roman proconsular Africa: Djebel Oust, Djebel Azeiz, Ain al Ksir and (presumably) Thala. The “Nero Chiota” limestone quarried on the Aegean island of Chios (Greece) was also included in the database.     

THE JUDICIOUS SELECTION AND PRESERVATION OF TUFF AND TRAVERTINE BUILDING STONE IN ANCIENT ROME*

The Republican and early Imperial monuments of Rome are, for the most part, built of tuffs quarried from at least seven pyroclastic deposits erupted from nearby Monti Sabatini and Alban Hills volcanoes. Remarks by Vitruvius (2.7.1–5), field observations of the monuments, and petrographic and rock testing studies of samples from Roman quarries demonstrate that Roman builders developed a good knowledge of the diverse material properties of the tuffs over centuries of use and exposure. Measurements of compressive strength, specific gravity, water absorption and adsorption of water vapour confirm that the petrographic characteristics of each tuff lithology strongly influence its strength and durability. Early construction utilized weakly durable, soft or vitric tuffs such as Tufo del Palatino or Tufo Giallo della Via Tiberina that are susceptible to decay, as at Temple C (290 bc ) of the Largo Argentina Sacred Area. Late Republican structures, such as the Temple of Portunus (80–90 bc ), employed somewhat durable, vitric–lithic Tufo Lionato reinforced with travertine, a durable limestone quarried near Tivoli. Roman builders selected the material properties of the tuffs to advantage for specific structural elements within large public monuments of the first century bc and the first century ad , as at the tabernae of the Forum of Caesar (46 bc ), where an upper storey of lightweight Tufo Lionato is supported by robust, lithic–crystal Lapis Gabinus pillars and flat arches reinforced with travertine. The tuffs are not very durable building stones; Romans preserved them with protective stucco, and travertine and marble cladding. Their high water intake, coupled with direct exposure to rain, daily fluctuations in relative humidity and urban weathering at present makes them especially vulnerable to decay.     

NON‐DESTRUCTIVE PORTABLE GAMMA RAY SPECTROMETRY USED IN PROVENANCING ROMAN GRANITOID COLUMNS FROM LEPTIS MAGNA,NORTH AFRICA*

Portable gamma ray spectrometry (PGRS) provides a non destructive means to analyst quantitatively large artefacts, such as building stones, for the radioelements K. U and Th. Nine Raman granitoid columns at the Leptis Magna Ruins in Windsor Great Park, London, were measured in situ by PGRS. Corrections for the environmental background contribution to the gamma ray flux measured, and for the shape and size of the columns, are described Comparison of the PGRS data with a radioelement data base for Roman granite sources indicates that most of the columns originated in the Troad area of Turkey. Two columns could not be unambiguously provenanced using PGRS alone because there is insufficient difference between radioelement concentrations in certain sources. However, non‐destructive measurements of magnetic susceptibility, used in conjunction with PGRS data, suggest that these two columns originated in the Kozak Daǧ, also in Turkey.     

SOURCES OF THE QUARTZITE OF SOME ANCIENT EGYPTIAN SCULPTURES

This article reports the results of analysis of samples collected from some Egyptian quartzite artifacts. such as statuary, dating from the New Kingdom. Most of the artifacts are located in Upper Egypt, but the results of analysis suggest that, until the middle of the fourteenth century B.C., the quartzite came from a more distant quarry near Cairo rather than from the quartzite quarries located near Aswan in Upper Egypt.     

MINERO‐PETROGRAPHIC AND GEOCHEMICAL CHARACTERIZATION OF ‘GRECO SCRITTO’ MARBLE FROM CAP DE GARDE,NEAR HIPPO REGIUS (ANNABA,ALGERIA)*

This work presents the results of the first mineralogical, petrographical and geochemical characterization of the marble quarried from the Cap de Garde headland, not far from Annaba (Algeria). This site is traditionally held by archaeologists to be the main source of supply of the so‐called ‘greco scritto’ marble, which was much used by the Romans for architectural and decorative–ornamental purposes, locally from the first century bc , and in Rome and central and southern Italy from the late Flavian period until the fourth century ad . The databank relating to the quarried material, created here for the first time, is used to establish the origin of ‘greco scritto’ found in six important Roman cities of North Africa: Hippo Regius and Cuicul (Djemila), in Algeria; Volubilis, in Morocco; Cyrene, in Libya; and Carthage and Utica in Tunisia. The results of this archaeometric study support the hypothesis (already put forward by authors) that the ‘greco scritto’used in the Roman Mediterranean originated from different sites, and suggest the existence of a number of North African quarries, also in the vicinity of Annaba.     

Facing two seas: Mediterranean and Atlantic contacts in the north-west of Iberia in the first millennium BC

Summary.  Despite the marginality of the region, the Later Bronze Age and Iron Age communities of the north-west of the Iberian Peninsula were engaged in active relationships with both Atlantic and Mediterranean peoples. Unlike other Atlantic regions, the area maintained direct contacts both with Mediterranean sailors and with the communities of the British Isles and north-western France simultaneously. The social relevance of these interactions and the range of imported goods transported varied throughout the first millennium BC. New evidence shows an intense involvement in Mediterranean trade from the fifth century BC onwards, while Atlantic contacts increased from the late second century BC, to reach a climax under Roman rule (first–second centuries AD).     

THE PORT OF THOLOS IN EASTERN CRETE AND THE ROLE OF A ROMAN HORREUM ALONG THE EGYPTIAN 'CORN ROUTE'

Summary. Roman provincial warehouses and rural horrea in the Aegean and eastern Mediterranean remain largely undocumented and their functions are poorly understood. A recent intensive archaeological survey at the bay of Tholos in the Kavousi area of northeastern Crete has investigated one such horreum and has explored the regional archaeological context of the building and its hinterland. The present study discusses the architectural form and archaeological context of this warehouse and assesses its function within the broader political and economic sphere of eastern Mediterranean trade routes in the second century A.D. Patterns of coastal urbanization, settlement development, and land use in eastern Crete in the Classical and Hellenistic periods, are examined as background for discussion of Roman rule, and as factors that are crucial in understanding the economics of settlement and the role of Cretan cities and the port of Tholos in the first and second centuries A.D.     

First Finding of Early Medieval Iron Slags in Sardinia (Italy): A Geochemical–Mineralogical Approach to Insights into Ore Provenance and Work Activity

At Santa Filitica, a Roman settlement in north‐western Sardinia occupied until the ninth century ad , archaeological excavations have found the remnants of a furnace consisting of a semi‐circular base made of stony slabs and tiles bound with clay. The furnace is attached to a wall of Roman age. Layers of the sixth century ad , bearing several variously oxidized slags, were found close to the furnace. These findings first testify to an ironworks in Sardinia, within a well‐defined context. XRPD and SEM–EDS mineralogical and textural analyses suggest that the slags derive from a bloomery and smithing work that was the first evidence of this type documented in Sardinia during the Early Middle Ages. Chemical analyses (performed with ICP and INAA) of rare earth elements and trace elements in two slags and in two Sardinian iron deposits allow some conclusions to be drawn on the local provenance of the ore. Our comparison of the Sardinian findings and some slags representative of archaeological smelting sites at the front of Elba island—the largest and longest lived iron‐working sites in the Mediterranean—also improves the methodology with which iron slags derived from different ores are compared.     

MAGNETIC SUSCEPTIBILITY VARIATIONS AT MONS CLAUDIANUS AND IN ROMAN COLUMNS: A METHOD OF PROVENANCING TO WITHIN A SINGLE QUARRY

Mons Claudianus in the Eastern Desert of Egypt was an important source of granodiorite for Roman columns. Computer contouring of 1119 magnetic susceptibility measurements at the quarry shows systematic variations, with low readings in the west of the quarry area and higher readings in the east. One hundred and seventy measurements on 62 columns of Mons Claudianus type in Rome and its environs were compared with the quarry readings, using a t-test based procedure. Some columns with distinctively low or high magnetic susceptibility could be provenanced very precisely to areas of about 700 × 700m within the 9km² of Mons Claudianus. Columns with susceptibility in the middle of the Mons Claudianus range could not be provenanced precisely. Results indicate early (first century AD) use of both west and east parts of Mons Claudianus, and contemporaneous use of several parts of the quarry, rather than systematic or sequential opening of the area. Columns found in third-century AD monuments, provenanced to the same parts of Mons Claudianus as earlier material, may indicate reuse of columns in some monuments. Magnetic susceptibility constitutes a portable and non-destructive method capable of provenancing not only to a quarry, but to specific areas within a single quarry.     

GREEN THESSALIAN STONE: THE BYZANTINE QUARRIES AND THE USE OF A UNIQUE ARCHITECTURAL MATERIAL FROM THE LARISA AREA,GREECE. PETROGRAPHIC AND GEOCHEMICAL CHARACTERIZATION

The quarries of ‘green Thessalian stone’ provide important information about the use of materials and the application of technology in late antiquity. This stone was used for decorative purposes in Imperial Rome and especially in Byzantium. Sarcophagi, column shafts, facing slabs, tubs, ambones, iconostaseis and baptismal fonts are still found in places stretching from Syria to Britain and from Tunisia to Germany, as well as Rome, Constantinople and Thessaloniki. There are two important areas of quarrying at the Chasanbali Hill in the Larisa area of central Greece. At the southern site, quarrying operations took place mainly in late Roman times, whereas the northern quarrying zone provided mostly raw materials for making pillars and other architectural pieces during the Byzantine period. Green Thessalian stone is composed of an ophicalcite, a mosaic of green serpentinite and white marble fragments. Mineralogically, the Larisa ophicalcite consists largely of serpentine, calcite, magnetite, haematite and chromite. Chemical analyses reveal a high quantity of CaO (26.39 to 31.00 wt%), while Cr varies between 940 and 1430 ppm. C and O isotopic compositions of the marble inclusions show δ¹³C values ranging from +3.12 to +3.31 ‰ and δ¹⁸O values from ?12.98 to ?13.11 ‰.     

THE NORTHERN COLOSSUS OF MEMNON: NEW SLANTS

Chemical and petrographic studies of the two 720-ton ‘Colossi of Memnon’ located near Luxor, and of Egyptian quartzite quarries indicate that the rear pedestal blocks of the northern statue were quarried at Aswan, while the other, main components of the monuments were quarried near Cairo. Our studies suggest that the rear pedestal blocks of the northern statue were part of the reconstruction project undertaken by Roman emperor Septimius Severus. Our studies of the tilting of the statues further suggest that the rear part of the lower torso of the northern statue was moved when the statue was reconstructed. Part of the present-day tilting of the northern statue probably occurred prior to the reconstruction.     

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’.     

PETROGRAPHIC AND ISOTOPIC CHARACTERIZATION OF THE MARBLE OF THE ISLAND OF TINOS (GREECE)*

Most outcrops of good‐quality crystalline marble in Mediterranean countries were exploited in Greek and Roman times. Hence, a wide variety of marble is now found in archaeological excavations. The precise determination of the provenance of a marble object is of great archaeological importance, and is now mostly obtained by coupling the petrographic study of a thin section with the analysis of the C and O stable isotopes, or by stereomicroscopy and EPR. The existing databases are considerable but still insufficient, because our knowledge about and study of ancient Mediterranean quarries remain incomplete. The contribution of this research is to add new petrographic and isotopic data on small quarries on the Greek island of Tinos that were exploited in antiquity. This marble belongs to the same geological horizon; it is quite pure, sometimes dolomitic and characterized by a low‐T, high‐P metamorphism that produced a limited recrystallization (MGS varying from 0.64 to 2.50 mm) on marine limestone protoliths. The petrographic features are quite distinctive: the fabric is strongly lineated and often stressed; and the accessory minerals are ubiquitary quartz, ore minerals, graphite and muscovite. As far as the isotopic data are concerned, δ¹³C_PDB varies from 1.1 to 2.7, and δ¹⁸O_PDB from ?1.7 to ?11.4. Both the features and the data have been compared with those of similar marbles used in antiquity, showing that their combination mirrors the fingerprint of the Tinos marble.     

SCIENTIFIC CHARACTERIZATION OF THE POHORJE MARBLES,SLOVENIA

As a former part of the great Roman Empire, Slovenia has many archaeological sites featuring buildings and objects entirely or partly constructed from marble whose provenance is doubtful. In Slovenia, the most probable source of such marble is the Pohorje Mountains. For the purpose of supporting further provenance studies, these marbles are fully scientifically characterized. The techniques used are petrographic and geochemical analysis, stable isotope ratio analysis and EPR spectroscopy. The results show that the Pohorje marbles are highly heterogeneous in both their isotopic and geochemical parameters as well as grain sizes. The parameters of the different Pohorje marble outcrops are compared between themselves and with the parameters of known ancient quarries in the Mediterranean and Austria. The use of a multi‐technique approach with combined parameters allows the best possible discrimination.     

THE TUNGSTEN AND TIN SIGNATURE OF IRON ORES FROM ELBA ISLAND (ITALY): A TOOL FOR PROVENANCE STUDIES OF IRON PRODUCTION IN THE MEDITERRANEAN REGION

The mineralogy, petrography and major‐ and trace‐element composition of iron ores from Elba Island (Tuscany, Italy), one of the most important iron sources in the Mediterranean area since the first millennium bc , revealed that hematite‐rich ores display prominent enrichments in W and Sn (up to 4950 μg g^?1 and 8400 μg g^?1, respectively). These two elements are hosted by tiny grains of W–Sn mineral phases (ferberite, scheelite and cassiterite) that are disseminated throughout the hematite matrix. A comparison with iron ores from many Italian and European localities (most of which were exploited in ancient times) suggests the uniqueness of the geochemical pattern of Elba Island hematite‐rich ores (i.e., high W and Sn, low Mo and low Cu, Pb and Zn). We suggest that this geochemical signature may represent a new provenance marker not only for discarded ore at smelting/smithing sites, but, possibly, also for metallurgical slag and smelted metal produced in the chaîne opératoire of the iron process.     

PROVENANCE DETERMINATION OF LAVA FLAGSTONES FROM THE ROMAN ‘VIA CONSOLARE FLAMINIA’PAVEMENT (CENTRAL ITALY) USING PETROLOGICAL INVESTIGATIONS*

Trachyte lava flagstones from the northernmost stretch of the Roman ‘Via Consolare Flaminia’pavement and trachyte lavas from the most exploited quarries in Roman times were compared from a petrological point of view. ‘Via Consolare Flaminia’was the most important route used by the Romans to reach northern Italy and all the northern provinces of the Empire. A provenance for the flagstones as coming from the trachyte quarries of the Euganean Hills (Veneto region, northern Italy) is suggested by the similarity of both the fundamental mineral assemblage and the major trace element geochemistry. The location of the quarries of the Euganean Hills next to the harbours of the northern Adriatic Sea strongly supports the hypothesis that the Romans carried the flagstones by ship towards the coasts of the central Adriatic Sea.     

The composition of ‘naturally coloured’ late Roman vessel glass from Britain and the implications for models of glass production and supply

Naturally coloured, blue or green are the most common glass colours found in assemblages from the Roman world from the end of the 1st century BC onwards. In the 4th century two different compositions have come to dominate this group, ‘HIMT’ and ‘Levantine 1’ glasses, both of which are now thought to have been produced in the eastern Mediterranean. Using Romano-British glass assemblages from the 4th and 5th centuries, it is shown here that although the two naturally coloured glass types predominate, by far the most common composition in British assemblages is HIMT, although older, earlier blue-green compositions are still present. The earliest date HIMT could be identified in these assemblages is around AD 330, although two distinct compositions can be identified within this group which relate to changes in composition over time. A similar change over time is seen in the Levantine 1 glasses. The reasons for these patterns within the assemblages are explored within the archaeological evidence currently available for glass production and consumption in the Roman world.     

‘GRANITO DEL FORO’ AND ‘GRANITO DI NICOTERA’: PETROGRAPHIC FEATURES AND ARCHAEOMETRIC PROBLEMS OWING TO SIMILAR APPEARANCE

Granitoid rocks were among the stone materials most frequently used for columns and pillars during the Roman period. When employed in Rome and the Mediterranean provinces, they were mainly quarried in Egypt, in Asia Minor and in Italy. Some of these rocks show very similar macroscopic features, so it is often very difficult to tell them apart with the naked eye. This is the case with the ‘Granito del Foro’ (or Marmor Claudianum), from the Gebel Fatireh, in the Eastern Desert, and the ‘Granito di Nicotera’ (Calabria), both exploited from the first century ad onwards. Both feature medium grain size and a white‐greyish colour with black patches. In order to obtain a certain microscopic and geochemical discrimination of these rocks, and to provide the first known petrographic classification of the ‘Granito di Nicotera’, a comprehensive mineralogical, petrographic and geochemical investigation was performed on several samples from the quarry. The results were compared with the corresponding data known for Marmor Claudianum in the literature. Good discrimination between the granites is possible, mainly on the basis of modal mineralogy and geochemical characteristics. The ‘Granito del Foro’ contains hornblende, while the ‘Granito di Nicotera’ contains muscovite, and has a distinctive peraluminous index and trace element abundances.