Search Results (25)

This paper presents the compositional characterisation of obsidian artefacts from the archaeological site of Maddalena di Muccia (Marche, Central Italy). The assemblage, spanning the Early Neolithic to the Copper Age, was chemically and petrographically investigated using two non-destructive X-ray analytical instruments: a wavelength-dispersive X-ray spectrometer and a scanning electron microscope equipped with an energy-dispersive X-ray spectrometer. Geochemical data allow secure attribution of the artefacts to their geological sources, confirming the predominant use of Palmarola obsidian during the Early Neolithic and documenting the continued circulation of obsidian also from other sources (Lipari and Monte Arci) into the Copper Age. Significantly, the Muccia assemblage provides the first evidence in the Adriatic area for the contemporaneous presence of multiple Monte Arci obsidian sub-sources (S.A. and S.C.). This compositional pattern suggests sustained long-term exchange networks involving obsidian, and highlights the role of central Adriatic sites within broader prehistoric interaction systems of the central Mediterranean. Full article

Obsidian was a key toolstone for the development of maritime lifeways in the western archipelago of southernmost South America. This area is a fragmented landscape where the major north–south movement of people along the Pacific was only possible by navigation because it is constrained by major biogeographic barriers. Two obsidian sources have been recorded, each one located on the extremes of the archipelago, and each has played a key role in the canoe-adapted societies that used them. As indicated by repeated inductively coupled plasma mass spectrometry analyses, obsidian from Chaitén Volcano to the north was distributed between 38°26′ S and 45°20′ S, and obsidian from Seno Otway to the south was distributed between 50° and 55° S, although it mainly occurred in sites close to the Strait of Magellan and within constrained time periods. This study explores the distribution of these two types of obsidians, their chronology, their frequencies in the archaeological record, the main artifact classes that are represented, and the technological processes in which they were involved. This examination indicates common aspects in the selection of high-quality toolstones for highly mobile maritime groups and discusses the different historical trajectories of two obsidians that appear decoupled across the Holocene. Full article

The Sierra de las Navajas is a Late Pliocene volcanic complex with a rhyolitic composition and peralkaline affinity. It is located on the northeastern edge of the Trans-Mexican Volcanic Belt in the state of Hidalgo. Within this rocky massif lies Cerro de las Navajas, the site of the most intensively exploited archaeological obsidian deposit in Mesoamerica. Obsidian extraction in this area has been carried out through open-pit mining and unique underground mining. The geological identity of the deposit encompasses the origin, distribution, and petrological characteristics of the obsidian from Cerro de las Navajas, determined through detailed geological mapping, petrographic study, and geochemical analysis. The results reveal the obsidian deposit’s style as well as its temporal and spatial position within the eruptive evolution of the region. The deposit originated from a local explosive eruptive mechanism associated with the partial collapse of a lava dome, forming a Block and Ash Flow Deposit (BAFD). The obsidian blocks, exploited by different cultures, correspond to the pyroclastic blocks within this deposit, which can reach up to 1 m in diameter and are embedded in a weakly consolidated ash matrix. The BAFD was later buried by (a) subsequent volcanic events, (b) structural adjustments of the volcanic edifice, and (c) soils derived from the erosion of other volcanic units. This obsidian deposit was mined underground from the Early Formative period to the Colonial era by the cultures of the Central Highlands and colonized societies. Interest in the vitreous quality and exotic nature of obsidian lithics from the BAFD led to the development of a complex exploitation system, which was generationally refined by the Teotihuacan, Toltec, and Aztec states. Full article

Minerals have played a fundamental part in prebiotic chemistry on Earth, catalyzing the synthesis of inorganic and even organic molecules, including macromolecules such as RNA or DNA. Minerals based on silica are some of the first inorganics to be found in very ancient mineral fossils. These minerals or even volcanic glasses rich in silica, such as obsidians (a naturally volcanic glass, which is in fact an igneous rock), play an important role as supporting materials for obtaining the silico-carbonates of alkaline earth metals (usually called biomorphs). This is because, in most radiolarians, diatoms, and foraminifera, their external shells are made up of silica (SiO₂). However, it has yet to be evaluated whether the silica contained in the minerals present in the prebiotic era of the Earth interacted with the chemical elements that were also present during that era. To evaluate whether obsidian participated in the formation of the first inorganic structures of pioneering organisms, this study aimed to synthesize calcium and barium biomorphs on igneous rock and to show that dissolved organic and inorganic molecules might have interacted with the molecules of obsidian, producing a plethora of shapes that mimicked the cherts of the Precambrian. Full article

The present work describes the first results of the project “Lipari Obsidian and Neolithic Human Communities in the Aeolian Islands”, which aims to study the connection between obsidian sources on the island of Lipari and Neolithic populations on the Aeolian archipelago in Italy. Obsidian is a natural volcanic glass used to produce chipped tools; in the Neolithic period it was the sharpest known material and its trade played an important role in the Mediterranean area. It is thus of particular interest for tracing prehistoric trading patterns. Indeed, Lipari obsidian has a wide distribution and has been found even in southern France, Dalmatia, Sicily and mainland Italy. To reach the project goal, we considered both raw materials from different obsidian geological samples and artefacts from Neolithic settlements on the Aeolian islands, and performed fission-track dating (FT), a radiometric technique that can be used for uranium-bearing minerals and glasses. The preliminary results facilitated the age determination of geological samples, which we could relate to the different eruption phases. Archaeological samples were also dated; their link with the studied volcanic deposits and lava flows made it possible to shed some new light on raw material procurement and on the ability of the Neolithic populations to move from their locations, with particular attention to the consequences of environmental features on the first human settlements on the Aeolian islands. Full article

The main objective of the present study was to develop a real-time mineral classification system designed for multiple detection, which integrates classical computer vision techniques with advanced deep learning algorithms. The system employs three CNN architectures—VGG-16, Xception, and MobileNet V2—designed to identify multiple minerals within a single frame and output probabilities for various mineral types, including Pyrite, Aragonite, Quartz, Obsidian, Gypsum, Azurite, and Hematite. Among these, MobileNet V2 demonstrated exceptional performance, achieving the highest accuracy (98.98%) and the lowest loss (0.0202), while Xception and VGG-16 also performed competitively, excelling in feature extraction and detailed analyses, respectively. Gradient-weighted Class Activation Mapping visualizations illustrated the models’ ability to capture distinctive mineral features, enhancing interpretability. Furthermore, a stacking ensemble approach achieved an impressive accuracy of 99.71%, effectively leveraging the complementary strengths of individual models. Despite its robust performance, the ensemble method poses computational challenges, particularly for real-time applications on resource-constrained devices. The application of this methodology in Mineral Quest, an educational Python-based game, underscores its practical potential in geology education, mining, and geological surveys, offering an engaging and accurate tool for real-time mineral classification. Full article

The efficiency of the vapor phase crystallization (VPC) process in zeolite formation using mixtures of a natural source (obsidian) and common waste materials (red mud and fly ash) was analyzed. The aim was to demonstrate that water molecules available during this treatment control mainly the synthesis of sodalite, regardless of the raw material used, as long as it is rich in amorphous silica and alumina pre-fused with NaOH. The data indicate that increasing the temperature to generate steam from distilled water during the VPC process results in the continuous transformation of amorphous material into sodalite and, subordinately, cancrinite. The formation of the newly formed phases was monitored by powder XRD and SEM. Full article

In the present work, more than one hundred and thirty lithic artefacts rediscovered in several archaeological sites dating from the Upper Palaeolithic to the Middle Ages from Calabria (Southern Italy) were petroarchaeometrically characterised through minimally invasive techniques. In more detail, 110 specimens were found in the Grotta della Monaca site (Sant’Agata di Esaro), and the other 23 belong to a collection kept in the Museo Nazionale Preistorico ed Etnografico “Luigi Pigorini” (Roma), coming from several localities (Longobucco, Spezzano della Sila, Cicala, Gimigliano, Roccaforte del Greco, and Bova). For preservation needs, 2 small axes in polished stone and 2 obsidians collected from Grotta della Monaca were analysed by absolutely non-destructive techniques. Optical and electron microscopic investigations, sometimes integrated with wavelength-dispersive X-ray fluorescence spectroscopy and X-ray diffraction spectrometry, allowed us to ascertain that the source area of all the lithic tools was in Calabria, except for obsidians, which come from the island of Lipari (Messina, Southern Italy). For a small number of particularly favourable cases, it was possible to define with great precision the outcrop area of the used rocks given their textural and mineralogical features. The specific source area contained a pickaxe originating from Cetraro–Fuscaldo metabasalt (lawsonite–albite facies) outcrops and two small axes in polished stone, one derived from migmatitic metapelites from Palmi and the other from meta-ultramafic rocks from Curinga. The choice of the used lithologies, harder or softer, had to be linked to the use that humans had to make of the lithic artefacts. Full article

With the recent introduction of handheld instruments for field use, laser-induced breakdown spectroscopy (LIBS) is emerging as a practical technology for real-time in situ geochemical analysis in the field. LIBS is a form of optical emission spectroscopy that is simultaneously sensitive to all elements with a single laser shot so that a broadband LIBS spectrum can be considered a diagnostic geochemical fingerprint. Sets of LIBS spectra were collected for seven obsidian centers across north-central California, with data processed using multivariate statistical analysis and pattern recognition techniques. Although all obsidians exhibit similar bulk compositions, different regional obsidian sources were effectively discriminated via partial least squares discriminant analysis. Obsidian artifacts from seven archaeological sites were matched to their putative sources with a high degree of confidence. Full article

Portable X-ray fluorescence (pXRF) is a useful geochemical technique employed to explore toolstone procurement strategies in the lithic record, commonly utilized in sourcing obsidians. Non-obsidian volcanic toolstones (e.g., dacites, rhyolites, basalts, and andesites) are abundant in interior Alaskan assemblages yet understudied compared to obsidian. Geochemical analyses of these non-obsidian materials offer the potential to gain new insights into ancient toolstone provisioning behaviors. This paper presents a synthesis of geochemical (pXRF) analyses of rhyolite artifacts, systematic regional raw material surveys, and lithic technological analyses collected from nineteen late Pleistocene and Holocene assemblages from the Nenana valley, interior Alaska. Previous research studies on archaeological rhyolites from the region are replicated, new rhyolite artifact groups are identified, and one new rhyolite source is reported and described here. Ultimately, this paper contributes to a growing body of geochemical research seeking to provide a more nuanced look at the complex late Pleistocene and Holocene record of eastern Beringia. Full article

Forty-two obsidian artifacts excavated at the site of Valdesi in western Sicily were analyzed to determine their geological sources and to reconstruct trade patterns. Non-destructive analysis was performed using a portable, non-destructive X-ray fluorescence spectrometer, with the calibrated element’s composition values compared directly with a dataset of geological samples from the Mediterranean and European sources that were analyzed with the same instrument. The results, based on straightforward X-Y graphs using the trace elements Rb, Sr, Y, Zr, and Nb, showed the presence of obsidian from two subsources on Lipari (Gabellotto Gorge, Canneto Dentro), two on Pantelleria (Balata dei Turchi, Lago di Venere), and one on Sardinia. The majority coming from Lipari coincided with the location of Valdesi, and nearly 20% came from Pantelleria, both consistent with the overall distribution patterns for Sicily, while the one from Sardinia is a unique discovery. These results are discussed in terms of the time period and context for Valdesi, as well as the open-water and land-based routes that must have been taken. Full article

The Inner Asian Mountain Corridor (IAMC) has been identified as a major pathway for the westward dispersal of millet from Northern China, where it was initially cultivated. Cross-disciplinary investigations are necessary to distinguish cultivated millet taxa from their wild relatives and to clarify the social context underlying millet adoption in novel environments. Despite the ambiguity in distinguishing Setaria italica from Panicum miliaceum or other Setaria species using conventional analysis of charred macro remains, recent attention has focused on the time gap between the introduction of S. italica to IAMC following P. miliaceum. Here, we employed a pottery impression casting method on materials from four Bronze Age sites in eastern/southeastern Kazakhstan to investigate the surface textures of grain impressions on the surface of pottery containers. We successfully identified both millets (Setaeria and Panicum) from three of the sites, Begash, Tasbas, and Dali in the IAMC. Based on our findings, two species of millet were introduced to the region within a much shorter range of time than previously estimated. In addition, the current evidence supports the premise that these cereals were likely utilized for human consumption. Full article

Obsidian is a natural volcanic glass formed after eruptions if very rapid cooling of lava occurs. In particular conditions, the lava silicate ions cannot reach the crystalline lattice ordered formation and assume a chaotic arrangement, giving origin to obsidian flows. Obsidian has been used since the Paleolithic period to make tools because of its durability; in the Neolithic period, its trade played an important role in the Mediterranean area, and currently, obsidian is of particular interest for tracing prehistoric trading patterns. In this work, we present a semi-quantitative approach, exploiting energy-dispersive X-ray fluorescence (ED-XRF) coupled with principal component analysis. We consider geological samples from the five main collection sites of archaeological interest in the Mediterranean Basin (i.e., Pantelleria, Lipari, Palmarola, and Sardinia islands in Italy and Milos Island in Greece) and obtain a reliable classification of the fragments’ provenance, also comparing chemical fingerprints with data from the literature. Reported results show that this non-invasive semi-quantitative protocol could ease the application to archaeological samples, such as blades and splinters, permitting the classification of artifacts found in the archeological sites of the Mediterranean area even when relatively few samples are considered. Full article

In the Pilauco site (40°34′11″ S, 73°06′17″ W; 13,570 ± 70–12,540 ± 90 14C year BP), a previous geochemical trace analysis suggested that the Puyehue-Cordón Caulle Volcanic Complex is the most likely source for obsidian and dacitic glass artifacts at Pilauco. It was hypothesized that the glassy rocks were probably collected from a pebble beach deposit, as deduced by the presence of crescentic percussion marks on the artefact cortexes. An experimental study was designed using pebble obsidian clasts. Bidirectional transport produced by the waves on a beach was imitated by an oscillating table, using time lapses equivalent to a transport of 0.7 to 20 km. One hundred clasts were randomly selected and marked. The morphological changes were registered, measured and photographed after seven sequential runs. At the end of the experiment at 20 km, the mass loss of rounded and fractured clasts was 5% and 11%, respectively. Crescent, circular, pseudo-circular and irregular percussion marks occurred in both types of clasts. In all cases, the crescent marks developed a pseudo-frosted surface appearance, giving a whiter tone that masks the black color of the obsidian, exactly as observed in the cortex of the artifacts knapped in dacitic glass at the Pilauco site. Thus, it is highly probable that the vitreous material was obtained from a beach sourced by the Puyehue-Cordón Caulle Volcanic Complex. Full article

Bioretention facilities with different inflow concentrations, growing media and plants were examined to determine whether the soil in these facilities was polluted with heavy metals and whether runoff had obvious toxic effects on plants. Using Beijing soil background value as the standard, the soils were evaluated by bioaccumulation index and single factor index. The results show that stormwater runoff containing Cu caused slight pollution in soils, and stormwater runoff containing Zn and Pb was not polluted. Nemerow comprehensive index evaluation revealed that the heavy metals content in the facilities containing vermiculite (a yellow or brown mineral found as an alteration product of mica and other minerals, used for insulation or as a moisture-retentive medium for growing plants) and perlite (a form of obsidian characterized by spherulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media) were higher than the standard. High influent concentration caused significantly higher heavy metals content in plants. While Pb accumulation in the two studied plants was the highest, Cu and Zn accumulation, which are essential for plant growth, was relatively low. The contents of the three heavy metals in the studied plants also exceeded their corresponding critical values. Full article