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The multidisciplinary analysis (dating, texture, total mineralogy) of two deep cores collected in the Donana National Park (SW Spain) allows to distinguish the main features of three tsunami deposits found in three different paleoenvironmental scenarios (TSU-1: inner area of an open lagoon; TSU-2: inner area of a restricted lagoon; TSU- 3: outer area of a restricted lagoon). The main textural feature of the inner lagoonal tsunami deposits is the increase in bioclastic sands, while the outer TSU-3 is composed almost entirely of medium and fine sands without bioclasts. The mineralogical analysis of TSU-1 and TSU-2 reveals a decrease in phyllosilicates in the basal layers of these tsunami deposits and a parallel increase of quartz, feldspars, dolomite and sometimes calcite. Silica is the main component of TSU-3, whose mineralogical composition changes progressively due to the action of tidal currents in the inlet lagoon on which it is deposited. This rich- SiO2 outer tsunami deposit is derived from the erosion of the adjacent aeolian systems, while the inner TSU-1 and TSU-2 were generated by the transport of bioclastic sands from the outermost parts through the lagoon (TSU-1), or through a nearby tidal channel (TSU-2).

A multidisciplinar analysis of sediments collected in diferent environments of the Doñana National Park (Guadalquivir estuary, SW Spain) provides an overview of the textural, mineralogical and physico-chemical parameters that control the distribution of benthic foraminiferal tests in this Biosphere Reserve. These microorganisms are absent in the fne quartzitic sands that constitute the substrate of temporary ponds with brief hydroperiods located in the dune systems and spits, as well as in other ponds with low conductivities or hypersaline conditions located in the inner marshlands or near the Guadalquivir river banks. Dead benthic foraminifera are mainly found on phyllosilicate-rich, silty-clayey substrates. The taphonomic analysis of the main species (Ammonia tepida, Haynesina germanica, Trochammina infata, Entzia macrescens) points to its deposit in situ. Cluster analysis permits to delimitate six foraminiferal assemblages. Cluster II (A. tepida+H. germanica) is the dominant assemblage in the central ponds and the margins of the main channels, while cluster IV (T. infata+E. macrescens) is restricted to some ponds located on the high marsh and cluster VI (Ammonia beccarii+Quinqueloculina spp.) is abundant on external beaches. Tidal fuxes cause the transport of these last marine benthic species and some plaktonic forms both to the inner areas of the estuary and to these beaches. info:eu-repo/semantics/publishedVersion

An interdisciplinary approach comprising archaeological, chemical, mineralogical, and luminescence data was applied to a better understanding of the fill dynamic and chronologies of a calcite-rich negative archaeological feature from Southern Portugal. This work aims to contribute to the assessment of the human involvement in the backfilling actions of a negative archaeological feature from a Chalcolithic site, thus better defining the moments of its destruction and/or abandonment. There are well-known limitations of luminescence dating of calcite-rich materials, particularly in the dose rate determination. In this work, a proposal of two innovative protocols to determine the dose rate of calcite-rich contexts is discussed. A clear improvement of the dose rate estimation was obtained by using the "radionuclide weighed" protocol. The comprehensive used methodologies enabled to define the infill phases and the sources of the infill materials. The luminescence profiling studies were also useful to describe the infill processes, highlighting their discontinuity and pointing to different deposition rates. The luminescence ages obtained, when using the "radionuclide weighed" protocol proposed in this work, are closer to the archaeological evidence of a Chalcolithic occupation. FCT (Portuguese Science and Technology Foundation)Portuguese Foundation for Science and Technology [UID/Multi/04349/2013, BL 36/2016_IST-ID, UID/GEO/04035/2013, PTDC-CS/ANT/104333/2008] FCTPortuguese Foundation for Science and Technology [SFRH/BD/62396/2009, SFRH/BPD/114986/2016] info:eu-repo/semantics/publishedVersion

Topsoils developed on different lithologies of all the geological units of the volcanic Brava Island (Cape Verde archipelago) were studied by neutron activation analysis and Mossbauer spectroscopy. Sampling was performed according to the recommendations of the IGCP 259 (“International Geochemical Mapping”). Significant chemical contents variations were found even within the same volcano-stratigraphic unit, inherited from the parent rock composition under the semi-arid climate of the island. The chemical heterogeneity of topsoils within the same geological unit, particularly in the Upper Unit, was evidenced by a multivariate statistical analysis. Some differences found can be related with the geographical location/underlying basement. High contents of Mn, Co, Ga, Ba, La, Ce, Nd, Sm, Eu, Tb, Ta, W, Th and U were observed in soils related to carbonatites and phonolites. REE and W can be used to trace outcrops of extrusive carbonatites. In general iron is strongly oxidized occurring in the silicates structure as well as in hematite, oxidized magnetite and maghemite. The global iron oxidation degree, the fraction of Fe 3+ in silicates and the fraction of nanosized oxides, which are higher in topsoils of the older units, may be an indicator of weathering degree. As, Br and Sb contents were also found to increase with weathering. Topsoils developed on extrusive carbonatites are clearly distinguished due to the absence of Fe 2+ in the silicate phases and the remarkable predominance of low oxidized magnetite.

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.

Barks from Prosopis juliflora (acacia) were collected in 12 sites of different geological contexts over the volcanic Fogo Island (Cape Verde). Elemental contents of Ba, Br, Co, Cr, Fe, K, Na, Zn and some rare earth elements (REE)-La, Ce, Sm, Eu, Tb, Yb, and Lu, were obtained for biological samples and topsoils by using k 0-standardized and comparative method of instrumental neutron activation analysis (INAA), aiming the evaluation of chemical elements uptake by acacia bark. This first biomonitoring study of Fogo Island showed that, in general, significant accumulations of trace elements present in high amounts in these soils occur. This can be partially explained by the semi-arid climate with a consequent bioavailability of chemical elements when rain drops fall in this non-polluted environment. REE enrichment factors (EFs) increase with the decrease of ionic radius. Heavy REE (HREE) are significantly enriched in bark, which agrees with their release after the primary minerals breakdown and the formation of more soluble compounds than the other REE, and uptake by plants. Among the potential harmful chemical elements, Cr appears to be partially retained in nanoparticles of iron oxides. The high EFs found in tree barks of Fogo Island are certainly of geogenic origin rather than anthropogenic input since industry and the use of fertilizers is scarce.

© 2015, Springer Science+Business Media New York. The “Great View of Lisbon” is one of the most remarkable blue-and-white Portuguese tile panels, which depicts the city before the tragic earthquake of 1755. This panel presents visible colored alteration in the glaze of tiles both from the exhibition and the depository of the Museu Nacional do Azulejo (Portugal). This work is a contribution to identify the origin of green stains in the glaze by using microbiological techniques, scanning electron microscopy with back-scattered electron imaging (SEM-BSE), Raman spectroscopy, and proton-induced X-ray emission (PIXE). The microbiological assays showed that the filamentous fungi were detected only at a frequency, JW and CA are thankful for the support by Grant CGL2010-16004 from the Spanish Ministry of Science and Innovation.

A uranium-rich aplite dyke with spheroidal alteration sited in the Beira uraniferous province, in Fornos de Algodres area (Northern Central Portugal) was studied, focusing on trace element distributions, especially U, in the aplite. A vertical profile, different size fractions, and various concentrically weathered layers of rock, were examined. The main goal of the work is to better understand the geochemical behavior and distribution of natural radionuclides in fine-grained granitic rocks, and changes that occur during weathering. The rock samples obtained from this site were examined using chemical and mineralogical methods: instrumental neutron activation analysis (INAA) and the X-ray diffraction (XRD). Field gamma spectrometry (FGS) and high resolution gamma spectrometry (HRGS) in the laboratory were also performed in order to determine concentrations of the natural radionuclides (K, Th and U) responsible for terrestrial gamma radiation, and for comparison of results with INAA measurements, enabling some information concerning radon losses. The U concentration in the studied samples vary between 4.5 and 83 ppm (always higher than upper continental crust value), with the higher values detected in the clay and sand fractions of weathered aplite (residual clay) and in the rounded boulders of aplite with spheroidal weathering, especially in the core. Strong variations in natural radionuclide contents, especially observed between residual clay and soil, relate to differences in source material. The large difference between pre-Rn and post-Rn values obtained by HRGS suggests high loss of radon (40% minimum), which is in accordance with field measurements. Due to generally high concentration of U, the aplite is a potentially strong source of emission of radon to the atmosphere with consequent radiological hazards.

A detailed survey of the most clay-rich rock units of the Meso-Cenozoic geological section exposed in the Algarve Basin (South Portugal) was performed and data were analysed for the grain-size distribution and mineralogy (whole rock and clay fraction), aimed at a compositional study of the clay-rich sediments and their depositional environment. Granulometry was obtained using wet sieving and laser diffraction by attenuation of X-rays, and the mineralogical study was carried out by X-ray diffraction.Most clay-rich rock units of the Algarve are classified as silty clays and clayey silts, and only a minority is coarser. The mineralogical study enabled us to define two main types of clays: (1) noncalcareous clays, consisting largely of quartz and clay minerals, with goethite as the typical Fe-rich phase (sediments of Carboniferous, Neogene and Quaternary age and Cretaceous siliciclastic clays); and (2) calcareous clays, which can be calcite-rich clays (Middle and Upper Jurassic) or dolomiterich clays (Triassic and Lower Jurassic), the latter typically containing hematite as an accessory phase. Plagioclase, K-feldspar, and Ti-oxides are often accessory phases, whereas ankerite, anhydrite, gypsum and opal are rare.In the clay fraction illite generally predominates, resulting probably from weathering of preexisting rocks, as well as the less frequent Fe-chlorite, pointing to incipient chemical alteration under semi-arid climatic conditions. Kaolinite occurs in diverse proportions, being especially abundant in Cretaceous and Cenozoic units; it is mainly related to chemical weathering in continental environments under humid conditions. As the Atlantic Ocean opened during Triassic and the continental environment evolved to a shallow-marine environment with evaporitic conditions, smectite became more expressive, being sometimes accompanied by other Mg-rich phases (chlorite, sepiolite, corrensite and palygorskite). Especially during the Cenozoic the proportion of different phases in the clay mineral association of the sediments reflects the control of tectonic movements and fluctuations in sea level during their deposition.

Artistic and historical examination of high-quality glazed terracotta sculptures displayed in various Portuguese museums point to their production in della Robbia workshop of Florence (Italy). A multitechnique analytical approach is applied for the first time to these sculptures, aiming to confirm their origin. Materials were analyzed using Instrumental Neutron Activation Analysis, Prompt Gamma Activation Analysis and X-ray Diffraction. The compositional results are similar to other della Robbia sculptures, suggesting a common origin for the raw material that was identified as carbonate rich marine origin marly clay. The applied firing temperatures was proved to be around 900 °C. The differences found within each sculpture are explained by the production technique of assembling separate parts to produce these huge sculptures, and the clay pit heterogeneity.

Neutron tomography (NT) has been applied to visualize the inner structure of ancient Portuguese glazed tiles undergoing conservation treatments. Neutrons have the advantage of interacting strongly with hydrogen, so NT is able to map hydrogenous compounds with high sensitivity. The present study explores its potential for assessing the distribution of the consolidant Paraloid B-72 inside tiles, to evaluate the efficiency of two different methods of treatment: brushing and immersion in solution. Using a prototype NT setup at the Reactor Portugues de Investigacao (Sacavem, Portugal), each two-dimensional image is obtained from a 90 s exposure, at a thermal neutron flux of 2 × 10 5 n cm −2 s −1 at the irradiation site. The neutron beam has a diameter of 5 cm, so fragments with outer dimensions up to 4.8 cm can be inspected. Samples are automatically rotated by an angle of 0.9° between successive images. Images were obtained before and after the application of the consolidant. The results obtained show that: (i) NT is a useful tool for visualization of the inner structure of ancient glazed tiles, and to assess penetration depth of consolidant and its distribution inside the tile; and (ii) brushing with 10% Paraloid ® B-72 in acetone solution appears to be more efficient than immersion. Neutron tomography showed a greater and more uniform retention of resin inside the tile if the brush is used to apply the consolidant, to increase the cohesion of the object.

A calcrete profile developed on the top of a calcareous consolidated dune located in a coastal area of NE Tunisia (semi-arid climate) was studied with the aim to investigate the behavior of the chemical elements (rare earth elements—REE—and other trace and major elements) during the processes associated with calcrete formation, particularly dissolution and precipitation of carbonates in the vadose zone. The profile shows a vertical sequence, with clear zonations from the surface downwards: a reddish soil at the land surface, a nodular horizon, a laminar-structured level, and the consolidated old dune. Chemical and mineralogical analyses of samples from all levels were performed by neutron activation analysis and X-ray diffraction (bulk samples and

The influence of carbonates in the temperature of Br volatilization during firing of clays and its implications in archaeometric studies are investigated. The main goal is to determine the circumstances in which Br content of fired products (“pottery”) can be considered inherited from raw material or added to ceramic pastes after production. Seven samples representing different types of clays (non-calcareous clays, calcite-rich clays and dolomite-rich clays) from Algarve region (South Portugal) were studied before and after firing at temperatures ranging from 300 °C to 1100 °C by steps of 100 °C. Original clays were characterized by major element geochemistry, obtained by X-ray fluorescence, and by mineralogy of bulk rock and

Mineralogical and chemical compositions of residual and sedimentary clays (bulk and A more successful result was the geochemical differentiation of clay types. The weathered schist presents greater enrichment in Cr, whereas the clay fraction of aplite-pegmatites shows enrichment in all the chemical elements studied. The sediments and weathered granites are not easy to differentiate; the best geochemical indicators are U (lower contents in clay-size fraction of sediments) and REE patterns in both bulk and clay-size fraction.

Altres ajuts: FCT (SFRH / BD /11020/2002) In cases where the provenance of raw materials used in the manufacture of local archeological ceramics is of interest, a detailed study of thermal transformations of minerals may be useful. The purpose of this study was to measure mineralogical transformations of different types of clays obtained during experimental firing runs, carried out at different temperatures, with the main goal of establishing Algarve reference groups based on the composition of raw material and high-temperature mineralogy, which may be compared with ceramics in studies of provenance. Eleven samples of clay-rich raw materials from the Algarve Basin (southern Portugal) were fired to temperatures ranging from 300 to 1100°C in increments of 100°C under oxidizing conditions. These were chosen to have variable chemical and mineralogical compositions, representing the main compositional range of the clay deposits from the region. Mineralogical and geochemical characterizations of the original clays were carried out by X-ray diffraction (XRD) and X-ray fluorescence (XRF), respectively. Mineral transformations on the fired products were also studied by XRD. Three groups of clays were distinguished according to the type of neoformed high-temperature minerals: (1) non-calcareous clays; (2) clays containing calcite as the only carbonate; and (3) clays with dolomite or dolomite + calcite. Firing of non-calcareous clays produced mullite at 1100-1200°C. Gehlenite and wollastonite formed by firing calcite-rich clays above 900°C, accompanied by anorthite or larnite in samples with small or large calcite contents, respectively. Firing of dolomite-rich clays at temperatures >900°C yielded a member of the gehlenite-åkermanite group and diopside. Anorthite, enstatite, periclase, forsterite, and monticellite may also form in the firing products.

Lower Cretaceous and Triassic-Hettangian clays from the Algarve Basin (South Portugal) were deposited in distinct environments during basin subsidence due to Pangea break up. The mineralogy, geochemistry and granulometry of 45 samples of both clay groups were studied, using X-ray diffraction, instrumental neutron activation analysis, X-ray fluorescence and laser diffractometry by attenuation of X-rays. Multivariate statistical techniques (principal component analysis and K-means clustering), after scandium normalization of chemical contents, were used to study simultaneously all data, enabling to distinguish the different clay types by establishing the best discriminatory parameters: high contents (in decreased order) of kaolinite, quartz, Chemical Index of Alteration (CIA), Ti, goethite, Hf, Si, > 63 μm fraction and Zr, characterize the group of clays from Cretaceous; while high contents of hematite, Mg, mobile elements (K, Cs and P), illite, Ca, phyllosilicates in general, Mn and dolomite, are associated to Triassic-Hettangian clays. This approach revealed useful to facilitate the integration of all data, as was possible to confront the geochemistry with the mineralogy, enabling the best palaeoenvironmental interpretations. In fact, the clay mineral assemblage is significantly influenced by the domi- nant weathering process and provides information on changes in aridity/humidity patterns.

Mineralogical transformations during firing of two extremely calcareous clays, one calcite and other dolomite rich, and relatively poor in silica were studied. Original clays were mineralogical and chemically characterized with X-ray diffraction (XRD) and X-ray fluorescence (XRF). Firing of both clays was carried out in the temperature range 300–1100 °C under oxidizing conditions and the mineralogical transformations were investigated with XRD, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy associated with energy dispersive X-ray spectroscopy (SEM-EDS). Important compositional differences in the neoformed phases were observed between calcite and dolomite rich clays. In the Ca-rich clay the assemblage gehlenite + wollastonite + larnite was observed. In the Mg(Ca)-rich clay the reaction products included akermanite, diopside, monticellite, forsterite, periclase and spinel. XRD and SEM-EDS showed the presence, in both clays, of a potassium–calcium sulfate in samples fired between 900 and 1100 °C.

This work enhances the importance on determining regional geochemical background by normalizing chemical data of archaeological ceramics, using one element as grain-size and mineralogical proxy, prior to any further statistical approach. It is well established that more relevant information can be derived from the concentration of any element when it is compared with some reference element. The main question is which element should be chosen to normalize concentration. A discussion on this issue is presented here. A case study is presented, which includes the geochemical tracing of Roman kilns productions, differentiating between and within two sedimentary basins pottery assembly, belonging to several Roman ceramic production centres identified in the Tagus and Sado basins of Portugal. Due to the homogeneity of the used raw materials (estuarine sediments), the distinction and establishment of signatures for each production center become difficult. A multivariate statistical approach after normalization of the chemical contents to a conservative element (Sc) is presented, well differentiating the three production centers and allowing the establishment of provenance for amphorae.

[EN]Bulk samples of mortars from the Santa Eulalia de Bóveda temple (NW Spain) have been characterized from a chemical and mineralogical point of view, with the aims of contributing technological and provenance inferences, and evaluating possible correlations with the various identified stages along historical periods of construction. Mortar samples were analyzed by X-ray diffraction and neutron activation analysis. Mineralogical associations found are similar (quartz, alkali feldspars, calcite and mica) for all samples, only varying in their proportions, mainly calcite. Statistical and geochemical studies allowed the differentiation of two main groups, enhancing definition of the granite nature of the aggregate, and of a significant variation in calcite proportion (lime binder). Two outlying samples were identified: one with higher calcite proportion and other corresponded to a plaster with a different raw material source. A clear correlation between the chemical groups and the independently defined chronological stages could not be found in this work. However, mortar samples from the earlier stage were associated with a higher aggregate/binder proportion., [ES]La mayoría de las muestras tomadas del conjunto monumental de Santa Eulalia de Bóveda (Noroeste de España) se han caracterizado desde un punto de vista químico y mineralógica, con el objetivo de obtener algunas conclusiones sobre aspectos tecnológicos y de procedencia de los materiales, así como evaluar las correlaciones que pueden existir con las distintas etapas constructivas identificadas mediante otro tipo de estudios. Las muestras de mortero se analizaron por difracción de rayos X y por activación neutrónica. Las asociaciones mineralógicas encontradas (cuarzo, feldespatos alcalinos, calcita y mica) son similares para todas las muestras, sólo variando en sus proporciones, principalmente de calcita. Los estudios estadísticos y geoquímicos permitieron diferenciar dos grupos principales, uno en el que se aprecia una mejora de la definición de la naturaleza del granito del agregado, y otro con una variación significativa en la proporción de calcita (cal aglomerante). Se identificaron dos muestras periféricas: una con una mayor proporción de calcita y otras corresponden a un yeso con una fuente de materia prima diferente. No se ha determinado en este trabajo una correlación clara entre los grupos químicos y las etapas cronológicas definidas de forma independiente. Sin embargo, en las muestras de mortero pertenecientes a las etapas más tempranas se identificó un agregado / aglutinante en mayor proporción que en las muestras pertenecientes a etapas posteriores.

International audience; Soils of the semi-arid area of the El Melah coastal lagoon (NE Tunisia), with a closing evolution dynamic, were studied aiming: (1) the chemical and mineralogical characterization of surface and subsurface layers of soil profiles from locations previously submerged and of soils developed on dunes; (2) to evaluate the dependence on the environment conditions of the geochemical patterns of the soils; and (3) to determine chemical and mineralogical variations with the emersion of the sediments resulting from the decrease in the extent of the area permanently covered by water in the lagoon. The compositional results obtained showed significant differences depending on the environment (littoral plain, old dunes and sandy spit), but soils of the different environmental zones studied do not appear to be significantly polluted as far as trace elements are concerned. Among the elements studied, high element/Sc ratios and variations were found for As, Sb and Zn. Antimony is more concentrated in coarser samples suggesting its adsorption in Fe or Mn oxides coating quartz grain surfaces. Arsenic and zinc may be incorporated into the carbonates structure, as well as adsorbed on, or coprecipitated with, iron oxides. Zinc may also be significantly incorporated in clay minerals. Iron was found to be more oxidized in the cultivated soil from the old dune strand; and more reduced in the sandy spit where ankerite occurs suggesting the reduction of Fe3+ in oxide/hydroxides by microorganisms and incorporation of Fe2+ in carbonates. REE patterns, particularly the HREE/LREE are correlated with carbonates, indicating preferential incorporation of the HREE in carbonates, and of the LREE in clay minerals/ iron oxides. High Ga contents were found in soils and sediments rich in clay minerals/Al, suggesting its incorporation in clay minerals structure. Therefore, Ga may be used as an indicator of the clay minerals proportion in sediments and soils. Carbonates, sulphates, besides Fe and/or Mn oxides and clay minerals, appear to play an important role on the trace elements distribution.

Carbonate-rich archaeological artefacts are difficult to identify and correlate between them and with raw materials of such heterogeneous geological sources, especially when only non-invasive analysis is possible. A novel combination of X-ray and neutron-based non-invasive analysis is implemented and used for the first time to study prehistoric stone idols and vessels, contributing to culture identity, mobility and interaction in the recent Prehistory of Southern Iberia. Elemental composition was obtained by prompt gamma activation analysis (PGAA) and external beam particle-induced x-ray emission (PIXE); homogeneity of the stone artefacts and the presence/absence of internal fractures were obtained by neutron radiography (NR). These atomic and nuclear techniques, simultaneously used for complementary chemical information, have been demonstrated to be of great value as they provide non-destructive compositional information avoiding sample preparation, crucial in so singular and rare objects. The obtained results, especially of PGAA, are very promising and useful in general assessments of provenance. The stone artefacts show signs of both nearby and long-distance procurement, as well as of unknown attribution.