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The Santa Vitória Chalcolithic site (southern Portugal) prompts several questions related to the provenance and production technology of artefacts. Archaeological ceramics from two sections of Ditch 1 of the Santa Vitória site were studied by neutron activation analysis and X-ray diffraction for the first time, with the main goal of contributing to the contextualization of the artefacts and better understanding their production processes/technologies and the provenance of raw materials. The results point to a local production of ceramics, since their mineral phases reflect the geological contexts around the archaeological site. The mineralogical assemblage indicates a firing temperature below 850 °C. Iron is the better discriminator of ceramics from both sections, which could be related to the addition of different proportions of temper grains during the ceramics' production. Although trace elements do not serve as discriminating geochemical indicators for the analyzed samples, they do imply a slightly higher heterogeneity in the composition of the ceramic paste from section 2. The negative Eu anomaly found in two samples is in accordance with the lower contents of Na2O, related to plagioclase weathering. Detailed studies on ceramics and potential raw materials are foreseen to assist in discussing the role of this Chalcolithic archaeological site at a regional level. [ABSTRACT FROM AUTHOR]

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New insights about the geochemical behavior of actinides and lanthanides in an old uranium mine are provided for the first time in this work. Fifteen samples (water, soil, and sediments) were collected inside and outside the Quinta do Bispo old mine (Portugal) in order to better understand the lanthanide and actinide behavior in the soil–water system. The chemical and mineralogical composition was obtained via ICP-MS, INAA, and XRD. The water sample from the open pit exhibits a higher U and REE dissolved concentration when compared to the other water samples. A positive Eu anomaly is found in this sample. The soil samples collected inside the mine area, including mine waste rocks and the minesoils surrounding the open pit, show uranium mineral phases, higher U contents, an enrichment of LREE relative to HREE, and a lower Th/U. This heterogeneity may be due to the open pit extraction and ore processes, as well as the percolation and water infiltration through the waste rock piles. Soils from outside the mine area have a similar mineralogical and chemical composition, despite their different geological context, which could be related to the influence of the granitic geological unit during the alluvial unit deposition. The sediments have similar REE patterns, negative Eu anomaly, and a high (La/Yb)N. [ABSTRACT FROM AUTHOR]

Topsoils developed in different geological formations/ages, and the top layer of the lava flow from the most recent eruption (2014/2015) of Fogo Island (Cape Verde archipelago), were studied. The specific objectives of this work are: i) to estimate the REE contents and patterns in the whole sample of topsoils developed on different geological formations/ages and their correlation with the iron speciation; and ii) to study the top layer of a lava flow from the most recent eruption after two years of exposure. REE contents are in general higher in the topsoils of the pre-caldera than in those developed on the post-caldera formation, particularly the light REE probably due to their incorporation into hematite. Positive Eu anomalies found in recent topsoils suggest the existence of hydrothermal processes with intrusion of hot fluids with higher concentration of Eu2+. In the top layer of the lava flow of the most recent eruption, Fe is incorporated in pyroxenes and iron oxides (magnetite and/or maghemite). This study can be a benchmark for further knowledge of the chemical evolution and weathering rate in semi-arid climate of Fogo Island.

REE have unique properties that are mostly used to manufacture high tech devices. Most REE have geochemical properties that cause them to be typically dispersed and not often found in concentrated and economically exploitable forms, and difficult to separate. The ENVIREE project aims to develop environmentally friendly and efficient methods for their extraction from secondary sources. REE contents of tailings from four legacy mining sites have been obtained by INAA and analysed by 57Fe Mössbauer spectroscopy. REE concentrations in the tailings of Covas and Cumieira are more dependent on the REE contents of the primary ores and the treatment to extract the target metals than on the nano-sized oxides present. The tailings’ size, REE contents and Mössbauer results support the selection of the Covas tailing as the one to be submitted for further steps of REE extraction on the framework of the project.

A lacustrine carbonate facies has been investigated in Middle Miocene successions of the western side of the Moura-Marmelar basin, Southern Portugal in order to evaluate paleoenvironments in which carbonates formed, by using geochemistry and mineralogy. The studied formation corresponds to a recent unearthed section of a calcrete with an homogeneous carbonate facies comprising fine, whitish, and powdery material, and the only detected difference is a slightly hardness decrease towards the top, as well as an increase of weathered rock fragments (schist). The calcrete is calcium rich, even some magnesium enrichment was observed at the middle level, which is differentiated by a general depletion of all chemical elements, particularly REE, in both the bulk and clay-size fraction. Regarding the mineralogy, calcite prevails, and dolomite is only present in the middle level of the calcrete, together with a smectite enrichment, suggesting changes to more alkaline and low drainage, lacustrine and arid to semi-arid conditions.

Roman military camps are temporary defensive enclosures, usually rectangular-like with rounded corners and defended by an external ditch and earthen embankment or stonewall. The use of remote sensing techniques has contributed to the identification of several new Roman military sites in northern Portugal and Galicia [1]. In the present work, two of those enclosures located in Northwest Iberia are considered: Lomba do Mouro (Castro Laboreiro, Melgaço and Verea, Ourense) and Alto da Raia (Tourém, Montalegre and Calvos de Randín, Ourense). Despite the increase in archaeological data concerning this type of enclosures, aspects related to the definition of the dynamics of construction, occupation and post-abandonment remain to be clarified. The Roman camps, being of temporary use, have a very limited associated material culture. Added to this constraint are signs of abrasion (acidic soils) and post-depositional taphonomic processes that make it difficult to establish the dynamics and chronology of the enclosures, constituting a challenging case study. In this sense, a multidisciplinary approach has been applied combining archaeological data, luminescence dating, and chemical and mineralogical compositional studies of the accumulated materials. The results of luminescence dating of the materials sealed by the stonewalls at Lomba do Mouro point to a Roman Late-Republican chronology. Concerning the materials accumulated in ditches and earthen embankment at Alto da Raia, the mineralogical composition points to the anthropogenic intention/selection of materials. Both studies, dosimetry by luminescence and compositional ones, are in accordance with an inversion of the stratigraphy related to the earthen embankment construction and with the hypothesis of reusing the nearby pre-existing prehistorical materials to infill the ditch. [ABSTRACT FROM AUTHOR]

The Mediterranean basin constitutes one of the best areas to analyse Neanderthal populations and lifestyles in South-Western Europe. In this context, new excavations conducted in the Middle Palaeolithic site of Cova del Puntal del Gat expand the information available regarding this rich region. In this study, new results are reported, including detailed studies on stratigraphy, lithic technology, anthracology, carpology, and zooarchaeology and taphonomy of macro and micromammals, with the final objective of characterizing the Neanderthals’ subsistence strategies and occupational patterns. These results are framed within a broader regional study perspective that includes MIS 5 and 4 sites. Chronostratigraphic review has enabled us to reorganize many sites that were originally included in MIS 3, towards older stages belonging to the end of MIS 4 and throughout MIS 5. [ABSTRACT FROM AUTHOR]

Abstract Old mine tailings from Northern and Central Portugal were studied in order to perform a radiological and chemical characterization. The evaluation of massic activity of natural radionuclides and concentrations in tailings of polymetallic and Ra/U mines was performed by gamma spectrometry and neutron activation analysis. Iron speciation was carried out by Mössbauer spectroscopy. In polymetallic tailings with physical ore processing (Cumieira and Verdes - exploited for Sn, Nb-Ta) higher contents of Th, 228Ra and 226Ra in the coarser materials occur, probably due to their presence in host rock and ore fragments. In finer tailings, washing may explain the lower 226Ra and 210Pb massic activity. In tailings with physical/chemical ore processing (Covas - exploited for W and Sn) high U contents and a tendency for higher 226Ra and 210Pb massic activity in the fine materials is observed, probably due to their incorporation in nano-sized particles of iron oxides. A high variation of the 210Pb/226Ra ratio occurs in polymetallic tailings; a deficit of 210Pb can be observed particularly in deposits of settling tanks drained from dumps of chemically treated ore. In Ervideira-Mestras tailings (Ra/U exploitation) where no ore process in situ was performed, a near equilibrium between 210Pb and 226Ra occurs. Dose risk assessment was carried out by calculating external outdoor Annual Effective Dose Rate; the dose rates in air due to terrestrial gamma radiation are low for the polymetallic tailings (<47 nGy/h), and higher for tailings of Ra/U (up to 4130 nGy/h), in the worst scenario. Graphical abstract Image 1 Highlights • Th and 228Ra are more concentrated in the coarser tailings of polymetallic mines. • Chemical treatments, drainage and deposition may originate high 226Ra and 210Pb. • 222Rn loss and 226Ra mobility explain low 210Pb/226Ra values in layered deposits. • 210Pb/226Ra≈1 and high external outdoor dose rate in surficial Ra, U mine tailings. • Nano-sized iron oxides may incorporate significant amounts of U and 226Ra. [ABSTRACT FROM AUTHOR]