Provenance Determination Research Articles

Mineralization, geochemical signatures, and provenance of stream sediments on the Jos Plateau, Northcentral Nigeria

This study aimed at determination of mineralization, geochemical signatures and provenance of stream sediments on the Jos Plateau, northcentral Nigeria. Ten (10) stream sediments samples collected were air-dried and subjected to X-Ray Fluorescence analysis. The SiO2 value of 49.79 to 77.03 wt%, Fe2O3 value of 1.30 to 28.84 wt%, Al2O3 value of 5.27 to 18.25 wt%, CaO value of 0.22 to 1.88 wt%, MgO value of 0.12 to 0.92 wt%, K2O value of 0.44 to 2.00 wt% and Na2O value of 0.02 to 0.65 wt%. The low values of CaO (0.22-1.88 wt %) and Na2O (0.02-0.65 wt %) could be associated with the destruction of plagioclase feldspar while low K2O composition (0.44-2.00 wt%) could be associated with the destruction of K-feldspar during weathering. The concentration of MnO (0.06-0.12 wt%) indicates manganite enrichment, the high TiO2 value (0.63-4.25 wt%) shows rutile enrichment while ZrO2 value (0.48-18.48 wt%) indicates zircon mineralization from the underlying lithologies. The high values of pathfinder elements (Y, Zn and Nb) could be attributed to the presence of Older and Younger Granites at the upstream of the study area. Samples 4, 5, 8 and 9 have Thorium (Th) concentrations >15 ppm threshold which point to areas favorable for Th mineralization. Enrichment Factor (EF) ranges from 3.03 to 42.42 indicating moderate, significant, very high enrichment and extremely high enrichment. The Contamination Factor (CF) of 1.27 to 201.03 indicates moderate and very high contamination possibly from geogenic sources. The provenance of stream sediments is associated with felsic and mafic sources

Geochemical Split Among the Suspended and Mud Sediments in the Nethravati River: Insights to Compositional Similarity of Peninsular Gneiss and the Deccan Basalt Derived Sediments, and Its Implications on Tracing the Provenance in the Indian Ocean

AbstractMajor, trace, and rare earth element (REE) geochemistry of sediments from a tropical mountain river is investigated to understand the behavior of chemical elements during weathering and transportation in a Peninsular Gneissic terrain. The results from this study are compared with the Deccan Basalt‐derived River sediments and the eastern Arabian Sea sediments with an intent to highlight the challenges associated with the provenance determination of sediments along the continental margin of India. The geochemistry of suspended particulate matter (SPM) and mud sediments (<63 μm) of the Nethravati River indicate that sediments are derived from a relatively homogenous lithology, characterized by intermediate rocks of tonalitic (low‐Al TTGs) composition. The tectonic origin of the source rocks discriminated using sediment geochemistry suggests an ocean island arc origin. The sediments experience intense chemical weathering in the source region. The elemental composition and their inter‐element relationships suggest differential chemical weathering of mineral phases fractionate mafic components and their secondary mineral products in SPM, and mixed sources dominated by felsic components and their secondary mineral products in mud sediments. Intense chemical weathering induces significant geochemical splits among the suspended and mud sediments. The transport of mafic‐biased sediments from Peninsular India to Oceans, and the geochemical similarity with Deccan Basalt‐derived sediments makes it challenging to track the Peninsular Gneiss‐derived sediment provenance along the continental margin of India using conventional elemental geochemistry. The inferences from this study have important implications for determining the sediment provenance along the continental margin of India.

New Strategies in Archaeometric Provenance Analyses of Volcanic Rock Grinding Stones: Examples from Iulia Libica (Spain) and Sidi Zahruni (Tunisia)

Archaeometry can help archaeologists in many ways, and one of the most common archaeometric objectives is provenance analysis. Volcanic rocks are often found in archaeological sites as materials used to make grinding tools such as millstones and mortars or as building materials. Petrographic characterization is commonly applied to identify their main mineralogical components. However, the provenance study of volcanic stones is usually undertaken by comparing geochemical data from reference outcrops using common descriptive statistical tools such as biplots of chemical elements, and occasionally, unsupervised multivariate data analysis like principal component analysis (PCA) is also used. Recently, the use of supervised classification methods has shown a superior performance in assigning provenance to archaeological samples. However, these methods require the use of reference databases for all the possible provenance classes in order to train the classification models. The existence of comprehensive collections of published geochemical analyses of igneous rocks enables the use of the supervised approach for the provenance determination of volcanic stones. In this paper, the provenance of volcanic grinding tools from two archaeological sites (Iulia Libica, Spain, and Sidi Zahruni, Tunisia) is attempted using data from the GEOROC database through unsupervised and supervised approaches. The materials from Sidi Zahruni have been identified as basalts from Pantelleria (Italy), and the agreement between the different supervised classification models tested is particularly conclusive. In contrast, the provenance of the materials from Iulia Libica remained undetermined. The results illustrate the advantages and limitations of all the examined methods.

Submarine volcanic microbiota record three volcano-induced tsunamis

The precise determination of sediment provenance not only yields insights into past tsunami events but also offers a window into understanding the genesis of tsunamis in distinct environments, such as volcanic regions. Through meticulous analysis of core samples from a lagoon in east of Korea Peninsula, we unveil three previously undocumented tsunamis and identify specific bacterial taxa associated with submarine volcanism during distinct periods. Specific bacterial species (Sulfurimonas_f and Alicyclobacillus ferrooxydans) and the presence of the silicoflagellate Dictyocha byronalis indicate deep-sea volcanic origins for certain sediment layers. The presence of microfossils, typically found in high-salinity pelagic environments during Event I, strongly supports the occurrence of a tsunami. These findings align with heightened volcanic activity on Ulleung Island during Event I and provide valuable chronological insights into submarine volcanic processes near Ulleung Island for Events II and III. Our study highlights these biological markers as crucial indicator for understanding past tsunamis arising from volcanic activity.

Tales unraveled through threads: Exploring the influence of natural dyes on the carbon and nitrogen isotope ratios of wool fibers from historical rugs

EA-IRMS has been used to find isotope ratio patterns as a way of ascertaining the provenance of materials in several fields of science. In this work, EA-IRMS analysis of δ13C and δ15N was used to study historical rugs’ raw materials. The influence of chromophores in the isotope ratio of wool was studied by dyeing contemporary wool with traditional dyestuff and analyzing it by EA-IRMS. Additionally, aiming towards provenance determination, historical rugs’ samples were analyzed. In general, δ13C and δ15N of contemporary dyed wool showed no significant difference between samples (P > 0.05) which rebutted the hypothesis that chromophore isotope ratios influence those of wool. Furthermore, δ13C and δ15N of both contemporary and historical wool samples were indicative of sheep diets comprised exclusively of C3 unfertilized plants. Exception was made for one rug whose δ15N values were compatible with organically fertilized plants. Particularly, δ13C and δ15N ratios of historical samples showed significant inter-rugs differences (P < 0.05) which could evidence meteorological changes over the years. Intra-rug differences detected in only one of the three rugs studied could be linked to changes in sheep diet and pastures management practices due to drought conditions. In sum, this work's results showed that is possible to use EA-IRMS analysis of δ13C and δ15N to study dyed wool without chromophore interference.

Oil Identification of harp seal and other select marine mammals

Because of the rich omega-3 fatty acids content, harp seal (Pagophilus groenlandicus) oil is a popular supplement that is packaged as pills in Canada and sold for medicinal purposes, although this practice is banned in the United States. Due to US regulations, it is important to be able to distinguish between fish oil and seal oil, but the taxonomic determination of oils provenance has been a difficult problem to solve. In this study, Direct Analysis in Real Time time-of-flight mass spectrometry (DART TOFMS) was used to analyze the chemotypes of blubber samples collected from seven species of marine mammals, including seals, sea lions, and a porpoise. Results indicated that the chemotype profiles found in negative-ion mode could be used to separate all of the species using Discriminant Analysis of Principal Components (DAPC). Consequently, this study suggests that it may be possible to identify the taxonomic source of marine mammal oils based on chemical chemotypes.

X-ray computed microtomography: A non-invasive and time-efficient method for identifying and screening Roman copper-based coins

This study utilises X-ray Computed Micro-Tomography (μXCT) as a non-destructive and non-invasive method to recover the original surface features and reveal the characteristics of encrusted, illegible Roman copper-based coins before any physical cleaning process is performed. The coins were retrieved from the topsoil during an archaeological survey in the countryside of the ancient city of Aquileia, Italy, and were severely degraded, covered with accumulated matter and pronounced encrustations developed over centuries of aging buried in soil. Despite their condition, most of the coins were identified from a numismatic standpoint using tomographic data alone, with the aid of reference images. They were subsequently cleaned using traditional manual methods and the results compared with μXCT. X-ray Fluorescence (XRF) analysis of the coins after the physical cleaning confirmed their numismatic attribution and revealed information regarding the influence of different alloy compositions on the applicability of the μXCT method, as well as on the corrosion process of the coins.This study showcases how the application of μXCT on fragile corroded metal artifacts prior to any intrusive manual procedures can expedite the identification process, mitigating the risk of information loss caused by physical handling and cleaning. This approach proves particularly valuable when dealing with large numbers of coins that would typically require restoration for identification purposes. It also emphasises the numerous advantages of using μXCT for coin identification, provenance determination, dating, virtual restoration, digitisation, and long-term preservation.

Composition of Rare Earth Elements in Fluvial Sediments of the Lesser Zab River Basin, Northeastern Iraq: Implications for Tectonic Setting and Provenance

During the past few decades, rare earth elements (REEs) have gained enormous attention in geochemical studies worldwide as a result of their important role in the manufacturing of high-tech equipment. REEs in river sediment have been widely used for provenance determination and in geochemical studies of continental crust, rock and sediment environments, and anthropogenic pollution. This study aims to elucidate the origin and tectonic setting of Little Zab River Basin (LZRB) sediments by examining 23 fluvial sediment samples of rare earth elements (REEs) collected from both the primary river and the inter-sub-basin regions during the rainy or high-flow season. The ICP-MS method was employed to analyze all samples to identify and assess the compositions of REEs. A fraction of the river sediments, smaller than 2 mm, which is more representative and more homogeneous, was used to carry out geochemical analysis. REE concentrations in the Little Zab River (LZR) and the upper parts of the LZRB were generally higher than those in the lower parts. The concentration of REEs in nearly all samples was lower than that of the North American Shale Composite (NASC), and the Upper Continental Crust (UCC), except for the sub-basin sediment Sbs2, which was higher than these references; also, the sediment sample Zrs4 was slightly higher than NASC. Light rare earth elements (LREEs) display enrichment relative to heavy rare earth elements (HREEs) with a range between 7.15 μg/g and 12.37 μg/g for LZR samples and between 5.95 μg/g and 13.03 μg/g for the sub-basin samples. The REE discrimination diagrams, along with the chondrodite-normalized pattern of the studied sediments, confirm that the sediment is predominantly sourced from the alkaline basaltic unit of the late Cretaceous Walsh group of an arc tectonic affinity.

Diagenesis in freshwater mussel shell and its implications for provenance determination – Evidence from the Kinlock Site, 22SU526 (Yazoo Basin, Mississippi, U.S.A.)

Freshwater shells from archaeological contexts hold the potential to allow sourcing of shell-tempered ceramics on the basis of their chemical composition. This application, however, requires understanding chemical interaction of shell with the burial environment. Here, we use material recovered at Kinlock (22SU526), a Late Woodland - to Mississippian-period site located in the Yazoo Basin, Mississippi, U.S.A. as a case study to evaluate the presence and impact of diagenesis on Unionid shells. Twenty whole shells recovered from the plow zone and the sub-plow zone are analyzed using a combination of thin sections, Scanning Electron Microscopy, and Inductively Coupled Plasma-Mass Spectrometry. Results show that, contrary to what might be expected, shells from the sub-plow zone are more affected by diagenesis than samples from the plow zone. The chemistry of the shells from the sub-plow zone is affected by modern human contaminants (fertilizers) within a perched water table, and is no longer representative of the original composition of these samples, compromising their use in provenance research. Shells from within the plow zone are less affected by contamination, making them potentially more useful to generate background data for provenance studies.

Nuclear forensic signatures of UO2 fuel pellets for differentiation and provenance determination illustrated using synthetic database

This paper presents a comprehensive nuclear forensics signatures analysis of UO2 fuel pellets, allowing their provenance to specific manufacturers. The study is based on a synthetic database designed for the 4th international Galaxy Serpent exercise circulation, which mimics real fuel pellet characteristics. The scenario of the exercise is completely fictional, including the data used and manufacturers' names, locations, etc. The signatures investigated include chemical form, pellet dimensions, equivalent boron content, Gd additive, impurities distribution, and isotopic composition. The consistency levels of the results, which determine the confidence in the provenance process, were divided into four levels due to the varying resolving power of the signatures. The paper emphasizes the importance of a graphical representation of the results to simplify interpreting multi-degree-of-freedom data, typical to nuclear forensics investigations, including the amalgamation of quantitative and qualitative information. The analysis connects 11 orphan pellets and a single UO2 powder to five manufacturers. The presented methodology offers a straightforward approach to data interpretation in nuclear forensic investigations and highlights the need for continued research and development in this field.

Botanical characterization and authentication of lavender essential oil using its volatile organic compounds and compound-specific carbon and hydrogen isotope ratio analysis

The determination of authenticity and provenance is one of the main issues in high-value natural products such as lavender (L. angustifolia) essential oil. Due to their high value, natural products are often totally or partially substituted with cheaper alternatives. Therefore, it is necessary to accurately characterize the composition of lavender essential oil and its related species, particularly lavandin (L. intermedia) essential oil, which is frequently used as an adulterant. In this study, we analyzed the most distinctive volatile organic compounds (VOCs) and their relative compound-specific stable carbon and hydrogen (δ13C and δ2H) isotope ratios in lavender, lavandin, and commercial lavender essential oil samples using fast GC-MS/MS and GC-IRMS methods and sparse Partial Least Square Discriminant Analysis (sPLS-DA) to classify and verify their botanical origin. For the first time, concentration ranges for 79 VOCs and the δ13C and δ2H values in 32 VOCs were used to characterize lavender essential oils. sPLS-DA models with either VOCs, δ13C and δ2H, or in combination successfully classify lavender and lavandin with 100% accuracy. VOCs such as camphor, borneol, eucalyptol, α-bisabolol, and α-pinene were found to be the most important variables for differentiating lavender oil from lavandin. Similarly, δ13C in camphor, eucalyptol, trans-β-ocimene and 3-octanone, and δ2H in α-terpineol and trans-β-ocimene and 3-octanone also differentiated lavender and lavandin oil. In addition, we demonstrated that compound-specific δ13C and δ2H detected the adulteration of natural lavender or lavandin oil if more than 15% of linalool, linalyl acetate, eucalyptol, and α-terpineol were of synthetic origin. These preliminary results with sPLS-DA models suggest that VOCs and compound-specific δ13C and δ2H can be a promising tool for the botanical classification of lavender essential oil and the detection of possible adulteration with synthetic compounds.

Genetic markers separate breeding populations of the endangered Antipodean Albatross and allow for determination of provenance of birds killed at-sea

ABSTRACT Advances in technology and software have provided higher resolution of genetic data. Re-analysis of genetic data from the endangered Antipodean Albatross using STRUCTURE shows that samples from the two main breeding populations on Antipodes and Adams Islands can be assigned correctly to each population using a set of nine microsatellite markers. The new analyses allow for assignment of bycatch birds killed off the east coast of New Zealand with high accuracy and show all of them originated from Antipodes Island. This highlights not only the importance of using genetic markers to inform conservation and management of endangered species but also the important advances in bioinformatics and the value of existing datasets.

Choosing the site, getting the stones, building the dolmens: local sourcing of andesites at the El Pozuelo megalithic complex (Huelva, Spain)

The geoarchaeological study focuses on the lithological characterization and provenance determination of the rocks of the El Pozuelo dolmens. The difficulty of identifying volcanic rocks in the intensely altered and deformed environment of the Iberian Pyrite Belt has required the implementation of a research methodology combining the archaeological and geological analysis of the megaliths and the area surrounding the Los Llanetes group. A total of 29 thin sections and 14 geochemical analyses (ICP-AES, ICP-MS and REE) have been carried out on samples from the dolmens and potential source areas, focusing on the chemical elements considered immobile during alteration processes. The petrological analyses confirm the identification of different andesite lithotypes and enable us to correlate the rocks used in the construction of the megaliths with source areas and quarries located within a 50–350 m radius. Several patterns are observed in the selection of the rocks, based on the material, visual and symbolic properties of the different lithologies. Foliated andesite is the most common stone used in the monuments, due to its excellent physical properties and technological suitability for extraction and transformation into megalithic supports. Other types of andesite (sheared, massive and amphibole-phyric), white quartz, ferruginous agglomerate and gabbro were also used for different architectural purposes. The results confirm the importance of locally available suitable rocks in determining site location, raw material procurement and monument construction during the Late Neolithic.

Utilizing Geochemical Analysis for Provenance Determination in Sedimentary Systems

Geochemical and isotopic analysis represents a potent approach for investigating sediment provenance, a crucial aspect for paleogeographic reconstructions, understanding the evolution of the Earth's crust and characterizing geology in areas that are no longer exposed at the surface. The sediment composition can be influenced by multiple processes including the weathering and erosion of the source rock, mixing with other sediment sources, grain size sorting and hydrodynamic processes such as water or wind transport. Additionally, climate and topography can impact the sediment composition by affecting the rate and nature of weathering and erosion as well as the transport and deposition of sediments. Moreover, post-depositional processes such as diagenesis and metamorphism have the potential to modify the original isotopic and geochemical composition of sediments. The objective of the present investigation is to conduct an overview of diverse geochemical proxies frequently employed in the evaluation of provenance as well as to assess their capabilities and limitations in estimating the origin of sediment. Additionally, statistical methodologies might be advantageous for sediment source determination, although it is crucial to acknowledge their restrictions and to merge them with traditional geochemical and isotopic techniques. A multidisciplinary strategy that encompasses several techniques and methodologies is probable to yield the most sturdy and dependable outcomes for identifying sediment provenance.

Multimethod approach to advance provenance determination of fish in stocked systems

Fish stocking occurs in aquatic systems for conservation purposes, to create or enhance recreational fisheries and to enhance wild-catch commercial fisheries. Identifying and quantifying the contribution of stocking efforts to wild populations is crucial to informing these management objectives. Provenance determination methods trade off accuracy, replicability, and cost-effectiveness at fishery-relevant scales. We present and assess multiple methods for provenance determination using a case study of barramundi ( Lates calcarifer) in the Dry Tropics region of northern Australia. A novel application of near-infrared spectroscopy (NIRS) is compared to two established methods for fish provenance, otolith microchemistry and genetic parentage analysis using microsatellites. The otolith microchemistry method was able to provide extremely high provenance resolution (&gt;99% accuracy). The microsatellite parentage analysis method had a slightly lower overall accuracy (95%), likely as a result of genetic introgression in this region. Provenance determination using otolith NIRS had the lowest overall accuracy (76%). Once limitations regarding spectral noise, image resolution, and sample size are addressed, NIRS may have potential for cost-effectively determining provenance in fish.

A novel measurement strategy and a dedicated sampling cell for the parallel characterization of organic and inorganic constituents in polymer samples by concurrent laser ablation ICP-OES and EI-MS

Polymeric composite materials are gaining importance due to their universal applicability and easy adaptability for their intended use. For the comprehensive characterization of these materials, the concurrent determination of the organic and the elemental constituents is necessary, which cannot be provided by classical analysis methods.In this work, we present a novel approach for advanced polymer analysis. The proposed approach is based on firing a focused laser beam onto a solid sample placed in an ablation cell. The generated gaseous and particular ablation products are measured online parallelly by EI-MS and ICP-OES. This bimodal approach allows direct characterization of the main organic and inorganic constituents of solid polymer samples.The LA-EI-MS data showed excellent agreement with the literature EI-MS data allowing not only the identification of pure polymers but also of copolymers, as demonstrated with acrylonitrile butadiene styrene (ABS) as the sample. The concurrent collection of ICP-OES elemental data is vital for classification, provenance determination, or authentication studies. The applicability of the proposed procedure has been demonstrated by analysis of various polymer samples from everyday use.

A novel use of a handheld elemental scanner for authenticating prawn provenance

Elemental profiling has emerged as a powerful end-to-end tool for authenticating origins of our food but its adoption by the industry is hindered by analytical delays and inaccessibility due to the laboratory-based nature of most instruments. To address these critiques, we evaluated a handheld x-ray fluorescence (XRF) scanner as a rapid in-situ approach for discerning provenance in a case study of black tiger prawns (Penaeus monodon) across Australia. To better understand the limitations and opportunities of the technology for seafood provenance, we evaluated provenance classes (site, jurisdiction, and production method), preparation method (cooked vs raw), and biological traits (carapace length, body weight, and sex) to disentangle the dominant influences on multivariate elemental fingerprints. Harvest site was found to be the dominant explanatory variable, indicating unique site properties eclipsed jurisdiction and production method (farmed vs wild) contributions. Raw samples were shown to be better suited for provenance determinations due to more pronounced variation in elemental fingerprints between classes. To simulate a real-world application, we constructed and tested machine learning classification models for identification of prawns back to harvest site, jurisdiction, or production method. The models employing raw prawn samples demonstrated high accuracies, with a classification accuracy of 87.5% to site; 98% accuracy to jurisdiction, and 100% accuracy to production method. Our results demonstrate the practicality of this first line of defence technology for provenance on the market floor or in supply chains. This innovative technique could facilitate the adoption of portable elemental profiling for provenance across supply chains, leading to a more sustainable and ethical seafood trade.

The provenance of Avalonia and its tectonic implications: a critical reappraisal

Abstract The late Neoproterozoic–Cambrian interval is characterized by global-scale orogenesis, rapid continental growth and profound changes in Earth systems. Orogenic activity involved continental collisions spanning more than 100 myr, culminating in Gondwana amalgamation. Avalonia is an example of arc magmatism and accretionary tectonics as subduction zones re-located to Gondwana's periphery in the aftermath of those collisions, and its evolution provides significant constraints for global reconstructions. Comprising late Neoproterozoic ( c. 650–570 Ma) arc-related magmatic and metasedimentary rocks, Avalonia is defined as a composite terrane by its latest Ediacaran–Ordovician overstep sequence: a distinctive, siliciclastic-dominated cover bearing ‘Acado-Baltic’ fauna. This definition implies that Neoproterozoic Avalonia may consist of several terranes, and so precise palaeomagnetic or provenance determination in one locality need not apply to all. On the basis of detrital zircon and Nd isotopic data, Avalonia and other lithotectonically related terranes, such as Cadomia, have long been thought to have resided along the Amazonian–West African margin of Gondwana between c. 650 and 500 Ma – Avalonia connected to Amazonia, and Cadomia to West Africa. These interpretations have constrained Paleozoic reconstructions, many of which imply that the departure of several peri-Gondwanan terranes led to the Early Paleozoic development of the Rheic Ocean whose subsequent demise in the Late Paleozoic led to Pangaea's amalgamation. Since these ideas were proposed, several new lines of evidence have challenged the Amazonian affinity of Avalonia. First, there is evidence that some Avalonian terranes may have been ‘peri-Baltican’ during the Neoproterozoic. Baltica was originally excluded as a potential source for Avalonia because, unlike Amazonia, arc-related Neoproterozoic rocks were not documented. However, subsequent recognition of Ediacaran arc-related sequences in the Timanides of northeastern Baltica invalidates this assumption. Second, detailed palaeontological and lithostratigraphic studies have been interpreted to reflect an insular Avalonia, well removed from either Gondwana or Baltica during the Ediacaran and early Cambrian. Third, recent palaeomagnetic data have raised the possibility of an ocean (Clymene Ocean) between Amazonia and West Africa in the late Neoproterozoic, thereby challenging conventional reconstructions that show the ‘peri-Gondwanan’ terranes as a contiguous belt straddling the suture zone between these cratons. In this contribution, we critically re-evaluate the provenance of the so-called ‘peri-Gondwanan’ terranes, the contiguity of the so-called ‘Avalonian–Cadomian’ belt and the validity of the various plate tectonic models based on the traditional interpretation of these terranes. In addition, we draw attention to critical uncertainties and the challenges that lie ahead.

Marble Architectural Elements and Liturgical Furniture of the Santa Giustina Basilica in Padova: New Archaeometric Data on the Importation of Proconnesian Marble in the Late Antique Adriatic

This paper examines eight marble samples from the architectural elements and liturgical furniture of the ecclesiastical complex of Santa Giustina in Padova (Italy), founded by the Rufus Venantius Opilio before AD 524. The provenance determination of the marbles was carried out by means of a multi-analytical approach combining mineralogical–petrographic investigations, performed by microscopic observations of thin sections, and the measurement of the ratios of stable carbon and oxygen isotopes. The results obtained were compared with up-to-date petrographic and isotopic databases (Antonelli and Lazzarini 2015), and they showed that the analyzed marbles come from the quarries of the island of Proconnesus in Asia Minor, modern Marmara Adası (Turkey). Archaeometric evidence, together with the stylistic and functional analysis of the pieces, suggests the direct importation of a complete set of sculptures, shipped at different stages of workmanship from the workshops of Constantinople and expressly ordered by a single patron, who can be identified as Opilio, founder of the basilica of Santa Giustina and praetorian prefect at the court of King Theodoric.

On the Use of White Marbles in Roman Forum Sempronii (Fossombrone, Marche, Italy): An Overview of the Archaeometric Data on Architectural Elements

This paper presents the results of the characterisation, identification, provenance determination, and quantification of the white, greco scritto-like and polychrome marbles used for architectural purposes at Forum Sempronii, a Roman town in the Marche region of Italy. Samples of five fragments of white marble and one fragment of a greco scritto-like marble have been studied using mineralogical and petrographic observations and stable isotope ratio analysis (SIRA) of carbon and oxygen. Polychrome marbles were macroscopically identified by comparison with reference samples and available image databases. Analytical results of the white and greco scritto-like marbles identified the material as coming from the quarries of Carrara (Luni, Italy) and Proconnesos (Marmara, Saraylar, Turkey) for white marble, and of Ephesos-Hasançavuslar for greco scritto-like marble. Further, at least eleven imported polychrome stone varieties were distinguished. The study clearly illustrates that Forum Sempronii had access to the main marble trade networks of the Roman Mediterranean. The early attestation of Proconnesian marble at the town’s augusteum (i.e., Augustan date) is unique for central Adriatic Italy.