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Phoenician colonisation of the Iberian Peninsula in the 1st millennium BCE introduced many novel and luxurious goods to the local populations of the Western Mediterranean. Among them, black-appearing glass beads are characteristic of indigenous female burials in Southern Portugal during the 6th century BCE. This study presents the results of the first comprehensive archaeometric investigation of black-appearing glass from Vinha das Caliças 4 (Portugal), and of black-appearing glass from the Iberian Peninsula in general. A multi-analytical approach employing Stereomicroscopic observation of manufacture and use traces, VP-SEM-EDS, μ-XRD, and LA-ICP-MS was used to cover a wide range of questions regarding technology and provenance. All analysed samples are natron glass. All samples of black and white beads are characterized by high Zr and low Sr values typically ascribed to the use of Egyptian sands. A comparison of the results of previous studies from the same site clearly demonstrates at least two geochemical provenances for Phoenician-traded glass beads, located in the Levantine region and Egypt, respectively. Furthermore, different colours of glass in individual polychrome beads exhibit similar trace element patterns, which might suggest these beads could have been produced close to glassmaking sites/regions. [ABSTRACT FROM AUTHOR]

A comprehensive investigation into the application of machine learning algorithms for accurately classifying mineral deposit types is presented. The study specifically focuses on iron deposits in the Portuguese Ossa-Morena Zone, employing a limited dataset of trace element geochemistry from magnetites. The research aims to derive meaningful methodological and metallogenic conclusions from the obtained results. The findings demonstrate that the combination of a restricted dataset of trace element geochemistry from magnetites with diverse machine learning models serves as a reliable tool for achieving precise classifications of mineral deposit types. Among the machine learning methods evaluated, random forest, naïve Bayes, and multinomial logistic regression emerge as the most accurate classifiers, whereas the support vector machine, the k-nearest neighbour, and artificial neural networks exhibit lower performance scores. By integrating all literature-proposed classifications, and applying them to selected iron deposits, confident classifications were obtained. Alvito and Azenhas are reliably classified as skarns, whereas Monges, Serrinha, and Vale da Arca are classified as either porphyry or a Banded Iron Formation (BIF). Notably, the classification of Orada proves cryptic, encompassing both BIF and volcanogenic massive sulphide (VMS) deposit types. Moreover, the application of machine learning models to pertinent case studies offers valuable insights not only for classifying mineral deposit types but also for discerning mixed or complex origins. This approach provides meaningful results that can aid in the interpretation of mineral deposit types and may facilitate the identification of new mineral exploration targets. The research highlights the robustness of machine learning algorithms in interpreting magnetite data and underscores their potential significance in exploration projects. [ABSTRACT FROM AUTHOR]

Recent archaeological excavations carried out in the western suburbs of Cordoba (Spain) brought to light numerous fragments of archaeological glass from the caliphal period (929–1031 CE). The typological and compositional analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of 66 fragments enabled the identification of different types of base glass and glass working techniques, identifying local productions, imports and decorative imitations of eastern models. The studied fragments include Mesopotamian, Levantine, Egyptian and possibly Sicilian soda-rich plant ash glass categories, and various glass-decorating techniques such as mould-blowing, pressing, cutting, staining or gilding. The systematic comparison of the trace element patterns of several relief-cut objects identified both imported ware and a locally manufactured sample, whereas all mould-blown pieces were made from locally sourced raw materials. Iberian glassworkers seem to have preferred mould-blowing, probably because of the distinct working properties of locally available high lead glass. The results thus confirm the continuous long-distance exchange of vitreous material, as well as the existence of multiple glassmaking centres in the Iberian Peninsula, illustrating a link between secondary glass working techniques and chemical composition. Furthermore, the identification of several fragments belonging to the same object based on chemical composition allowed us to reconstruct entire vessels and thereby expand the repertoire of known typologies circulating in Umayyad Spain. [ABSTRACT FROM AUTHOR]

This study presents the first comprehensive analysis of glass compositions from Visigothic Spain using high resolution laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Major, minor and trace element patterns of 169 well-dated samples from three rural Iberian sites (Congosto, Gózquez and El Pelícano) have brought to light major chronological developments in the production, circulation and use of glass between the fifth and the eighth century CE. The data identify four distinct compositional groups of Egyptian and Levantine origin. Egyptian Foy 2.1, Foy 2.1 high Fe and so-called Magby alongside Apollonia-type Levantine I were the main glass types of the Visigothic period. Due to the tight dating of the majority of the samples, we were able to reveal fundamental changes in the geographical scope of glass supplies to the Iberian Peninsula, and to refine the chronological range of the known primary production groups. The glass group commonly known as série 2.1 or Foy 2.1 started being produced already during the second half of the fifth century. The appearance of Foy 2.1 high Fe can likewise be moved forward to the first half of the sixth century. A plant-ash group referred to as Magby was introduced around the middle of the sixth century. Egypt was undeniably the main supplier of raw glasses to the Iberian Peninsula up to the mid-sixth century CE, after which the Levantine I group became the prime glass type among the analysed assemblages. In the final stages of the Visigothic Kingdom and the early years of Islamic dominion, there is a noticeable drop in the absolute quantity of glass available, together with an increase in recycling. The implications of these transformations in the supply of glass for the organisation of Mediterranean trade are discussed. • LA-ICP-MS analysis of Visigothic glass assemblages from the Iberian Peninsula. • Identification of four main primary glass groups from the eastern Mediterranean. • Temporal shift in the supply of Egyptian compositional types towards Levantine glass. • Revised chronological ranges for Foy 2.1 and Foy 2.1 high Fe production groups. [ABSTRACT FROM AUTHOR]

The Ossa-Morena Zone (OMZ, SW of the Iberian Peninsula) is a geotectonic domain that comprises a set of diversified ore deposits formed from Cambrian to Carboniferous-Permian ages. The Montemor-o-Novo – Ficalho Fe-Zn-(Pb) belt was a productive mining sector until the first half of the 20th century with potential for future mineral exploration, although the mechanisms responsible for ore deposition are, in some cases, poorly constrained. In this study the trace element composition of a large set of orebodies belonging to three iron deposits is examined, and the first δ18O analysis of magnetite from the Portuguese sector of OMZ is reported. Outcrop and drill core magnetite samples were collected from the Montemor-o-Novo Iron Complex (MIC), and from the Alvito and Azenhas-Orada deposits. New magnetite LA-ICP-MS data from the carbonate-hosted MIC deposits, classified as SEDEX-VMS, and from the Alvito and Azenhas-Orada skarn deposits are complemented by previously published data. This approach contributes to the classification of these deposits and provides new discriminatory proxies for skarn deposits worldwide. Close to 1000 LA-ICP-MS and EPMA magnetite spot analyses is explored, complemented by EPMA analysis of representative mineral phases from the host rocks. Three deposits from the MIC (Monges, Vale da Arca, and Serrinha) were studied, in which magnetite reveals a wide range of textures and trace element compositions. Using the Al + Mn vs Ti + V diagram the magnetite from the MIC is hardly discriminated from the magnetite data from the skarn deposits. Hence other discriminant factors have been used. Magnetite from the MIC is characterized by low contents of Co, Zn, and HFSE (e.g. Ta, Nb), and shows a close relation with low-temperature hydrothermal magnetite as revealed by the multivariate diagrams of trace elements. Skarn magnetite display high concentrations of temperature-dependent elements such as Ti, V, Al, Ga, Sn, Cr, and HSFE. Additionally, high contents of Co and Zn are ubiquitous for first generation magnetite from the skarn deposits, which might indicate that the ore source was enriched in such elements. Primary magnetite from the MIC deposits revealed δ18O signatures in the range 4.3 ‰ to 9.0 ‰ which, combined with magnetite trace element composition, suggests extensive overprinting of the primary signatures by late metamorphic events. Primary magnetite from the Azenhas-Orada deposits revealed δ18O signatures (4.0 ‰ – 5.6 ‰) suggesting a magmatic derived source for the mineralization, corroborating the hypothesis proposed in recent works. The δ18O signatures of magnetite from the Alvito skarn deposit indicate that extensive interactions between a magmatic fluid, with lighter 18O signatures, and the dolomite-calcite host rock, with heavier 18O signatures, have occurred. The results outline the potential of allying powerful multielement analysis of magnetite with stable isotope analysis and contribute to the refinement of geological models in the Ossa-Morena Zone that can be used in future mineral exploration. • Oxygen isotopes and trace element analysis of magnetite from SW Iberia Fe deposits • Constraints on the formation of skarn and volcanogenic-exhalative deposits • Proposition of the Co vs. Zn biplot as a valid metallogenic discriminatory method • δ18O signature of skarn magnetite indicates a magmatic contribution to ore genesis. • Results suggest extensive post-deposition overprinting of ores in the MIC deposits. [ABSTRACT FROM AUTHOR]

Abstract: LA-ICP-MS U–Pb ages of detrital zircons from eight siliciclastic samples from the Basal units of the Variscan allochthonous complexes of NW Iberia are used to establish the maximum depositional age and provenance of two tectonically-stacked metasedimentary sequences deposited on the outermost margin of Gondwana, and subsequently involved in the Rheic Ocean suture. The maximum depositional ages for the two sequences is latest Neoproterozoic and latest Cambrian, respectively. The age spectra are also used to discuss the paleoposition of the NW Iberian basement on the continental margin of Gondwana prior to the opening of the Rheic Ocean, which is tentatively placed in northern Africa, between the West African and Saharan cratons. Based on similarities and differences with age data from the NW Iberian autochthon and other allochthonous terranes involved in the Rheic suture, the relative proportions of Mesoproterozoic zircons in both assemblages are proposed as markers of proximity to the eastern part of the West African craton during late Neoproterozoic and late Cambrian. The geodynamic processes that took place along this part of Gondwana during the late Neoproterozoic, late Cambrian and Early Ordovician are discussed in the light of the LA-ICP-MS results, as well as the sedimentological record, magmatic evolution and plate tectonic setting of NW Iberia. These processes are linked to late Neoproterozoic and Cambro-Ordovician subduction events beneath the northern Gondwanan margin. [Copyright &y& Elsevier]

The fluorite deposits of Asturias (northern Iberian Peninsula) are hosted by rocks of Permo-Triassic and Palaeozoic age. Fluid inclusions in ore and gangue minerals show homogenization temperatures from 80 to 170°C and the presence of two types of fluids: an H2O–NaCl low-salinity fluid (<8 eq. wt% NaCl) and an H2O–NaCl–CaCl2 fluid (7–13 wt% NaCl and 11–14 wt% CaCl2). The low salinity and the Cl/Br and Na/Br ratios (Cl/Brmolar 100–700 and Na/Brmolar 20–700) are consistent with an evaporated sea water origin of this fluid. The other end-member of the mixture was highly saline brine with high Cl/Br and Na/Br ratios (Cl/Brmolar 700–13 000 and Na/Brmolar 700–11 000) generated after dissolution of Triassic age evaporites. LA-ICP-MS analyses of fluid inclusions in fluorite reveal higher Zn, Pb and Ba contents in the high-salinity fluids (160–500, 90–170, 320–480 p.p.m. respectively) than in the low-salinity fluid (75–230, 25–150 and 100–300 p.p.m. respectively). The metal content of the fluids appears to decrease from E to W, from Berbes to La Collada and to Villabona. The source of F is probably related to leaching of volcanic rocks of Permian age. Brines circulated along faults into the Palaeozoic basement. Evaporated sea water was present in permeable rocks and faults along or above the unconformity between the Permo-Triassic sediments and the Palaeozoic basement. Mineralization formed when the deep brines mixed with the surficial fluids in carbonates, breccias and fractures resulting in the formation of veins and stratabound bodies of fluorite, barite, calcite, dolomite and quartz and minor amounts of sulphides. Fluid movement and mineralization occurred between Late Triassic and Late Jurassic times, probably associated with rifting events related to the opening of the Atlantic Ocean. This model is also consistent with the geodynamic setting of other fluorite-rich districts in Europe. [ABSTRACT FROM AUTHOR]

The Azenhas and Alvito Fe-deposits are located at SW of the Iberian Variscan belt, in a wide Fe-Zn ore district (Montemor-Ficalho Belt), part of the Ossa-Morena Zone. Both deposits are dominantly composed of magnetite ores that display distinct ore formation processes and, at the Azenhas deposit, massive magnetite ores are mainly hosted in amphibolites (Middle Cambrian – Ordovician), with a genesis arguably associated with metamorphic-metasomatic reactions promoted by fluid circulation through several thrust faults that led to and expressive tectonic pilling. Contrastingly, the Alvito massive magnetite ores are formed by the emplacement of a gabbro-dioritic suite in contact with calcite-dolomite marbles, constituting a typical calcic exoskarn Fe-skarn deposit. Primary and secondary magnetite were identified and characterized, and further selected for in situ laser ablation coupled inductively mass spectroscopy (LA-ICP-MS) trace element analysis. Results show that primary magnetite (Mag I) from the Azenhas deposit is discriminated by higher concentrations of Mg, Cr, Mn, Zn, Co, and Sn, whereas secondary magnetite (Mag II) is depleted in most trace elements, although displaying relatively higher concentrations of V, Ga, Mo, and Pb. The application of T Mg-Mag geothermometer reinforced the discriminatory indexes, with Mag I displaying higher-temperature estimations (ca. 770 °C) when compared to Mag II (ca. 420 °C), thus suggesting that primary ores are associated to higher temperature processes than previously assumed. Characterization of the ores from Alvito deposit revealed primary magnetite characterized by abundant ilmenite and Al-spinel oxy-exsolutions which led to high measured Al concentrations in magnetite. The trace element content indicates high-temperature hydrothermal magnetite, underlining the contribution of hot hydrothermal fluids from the igneous body emplacement, also supported by the T Mg-Mag geothermometer (ca. 685 °C). The anomalous presence of Co (max. 156 ppm) and Ni (max. 100 ppm) concentrations in Mag I from Alvito, along with pentlandite-magnetite assemblages, suggest that prone conditions were sustained for the development of Ni-bearing ores and that magnetite composition could be an interesting geochemical proxy for the exploration of such mineralization. The Mn + Al versus Ti + V discriminant diagram shows that primary ores from both deposits plot in the skarn field. The combination of magnetite analyses with whole-rock geochemistry and field geology, allowed us to define criteria that can be applied in the discrimination of Fe-deposits and contribute to improve the geological models of the studied ore deposits, thus beneficiating future exploration in SW Iberia. [Display omitted] • Chemical and textural characterization of skarn magnetite ores is provided. • Primary ores with affinities to high-temperature hydrothermal magnetite • Co incorporation is temperature controlled and can be used as a discriminant element. • Primary magnetite from both deposits displays Zn contents up to 1085 ppm. • Magnetite geochemistry is used as a geochemical proxy for redefinition of geological models. [ABSTRACT FROM AUTHOR]

Monazite and rutile occurring in hydrothermally altered W mineralizations, in the Echassières district of the French Massif Central (FMC), were dated by U-Pb isotopic systematics using in-situ Laser ablation-inductively coupled plasma–quadrupole mass spectrometry (LA-ICP-MS). The resulting dates record superimposed evidence for multiple percolation of mineralizing fluids in the same area. Cross-referencing these ages with cross-cutting relationships and published geochronological data reveals a long history of more than 50 Ma of W mineralization in the district. These data, integrated in the context of the Variscan belt evolution and compared to other major W provinces in the world, point to an original geodynamic-metallogenic scenario. The formation, probably during the Devonian, of a quartz-vein stockwork (1st generation of wolframite, called wolframite "a"; >360 Ma) of porphyry magmatic arc affinity is analogous to the Sn-W belts of the Andes and the Nanling range in China. This stockwork was affected by Barrovian metamorphism, induced by tectonic accretion and crustal thickening, during the middle Carboniferous (360 to 350 Ma). Intrusion of a concealed post-collisional peraluminous Visean granite, at 333 Ma, was closely followed by precipitation of a second generation of wolframite (termed "b"), from greisen fluids in the stockwork and host schist. This W-fertile magmatic episode has been widely recorded in the Variscan belt of central Europe, e.g. in the Erzgebirge, but with a time lag of 10–15 Ma. During orogenic collapse, a third magmatic episode was characterized by the intrusion of numerous rare-metal granites (RMG), which crystallized at ~310 Ma in the FMC and in Iberia. One of these, the Beauvoir granite in the Echassières district, led to the formation of the wolframite "c" generation during greisen alteration. [ABSTRACT FROM AUTHOR]

• Paleolithic lithic tools from Montlleó open-air site (NE Iberia) have been studied. • Two geochemical techniques have been used: ED-XRF and LA-ICP-MS. • Results suggest that the Pyrenees were not a barrier during the Upper Paleolithic. Chert was one of the most used lithic raw materials by Palaeolithic groups to make their tools. Their characterisation is essential for determining their provenance and inferring mobility patterns and lithic procurement strategies. The Pyrenees -a mountain range traditionally viewed as a natural boundary between the Iberian Peninsula and the rest of the continental Europe- are the location of a number of Palaeolithic human occupations dating to the Late Glacial Maximum (LGM). One example is the open-air site of Montlleó (Prats i Sansor, Catalonia, Spain), located at more than 1000 m asl, whose excavation has demonstrated that the ice retreat in this area was earlier than believed and humans took advantage of this new environment as evidenced by the variety of raw materials in the community's lithic assemblage. Energy-dispersive X-ray fluorescence (ED-XRF) and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are applied to a representative sample of chert tools from Montlleó as well as six geological formations from different areas of the Pyrenean region. The aim was to identify potential raw material sources using major, minor and trace elements. Results suggest that the Pyrenees were not a barrier to human mobility at that time. [ABSTRACT FROM AUTHOR]