Jose Mirao - Academia.edu (original) (raw)

Papers by Jose Mirao

Applied Sciences

The potential for mineral carbonation of CO2 in plutonic mafic rocks is addressed through a set o... more The potential for mineral carbonation of CO2 in plutonic mafic rocks is addressed through a set of laboratory experiments on cumulate gabbro and gabbro-diorite specimens from the Sines Massif (Portugal). The experiments were conducted in an autoclave, for a maximum of 64 days, using a CO2 supersaturated brine under pressure and temperature conditions similar to those expected around an injection well during early-phase CO2 injection. Multiple techniques for mineralogical and geochemical characterization were applied ante- and post-carbonation experiments. New mineralogical phases (smectite, halite and gypsum), roughness increase and material loss were observed after exposure to the CO2 supersaturated brine. The chemical analysis shows consistent changes in the brine and rock specimens: (i) increases in iron (Fe) and magnesium (Mg) in the aqueous phase and decreases in Fe2O3 and MgO in the specimens; (ii) a decrease in aqueous calcium (Ca) and an increase in CaO in the cumulate gabbr...

Journal of Raman Spectroscopy

Minerals

Four pure hydrogenetic, mixed hydrogenetic-diagenetic and hydrogenetic-hydrothermal Fe-Mn Crusts ... more Four pure hydrogenetic, mixed hydrogenetic-diagenetic and hydrogenetic-hydrothermal Fe-Mn Crusts from the Canary Islands Seamount Province have been studied by Micro X-Ray Diffraction, Raman and Fourier-transform infrared spectroscopy together with high resolution Electron Probe Micro Analyzer and Laser Ablation Inductively Coupled Plasma Mass Spectrometry in order to find the correlation of mineralogy and geochemistry with the three genetic processes and their influence in the metal recovery rate using an hydrometallurgical method. The main mineralogy and geochemistry affect the contents of the different critical metals, diagenetic influenced crusts show high Ni and Cu (up to 6 and 2 wt. %, respectively) (and less Co and REY) enriched in very bright laminae. Hydrogenetic crusts on the contrary show High Co and REY (up to 1 and 0.5 wt. %) with also high contents of Ni, Mo and V (average 2500, 600 and 1300 μg/g). Finally, the hydrothermal microlayers from crust 107-11H show their enr...

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, Jun 5, 2018

This work explores the combination of µ-Raman spectroscopy and scanning electron microscopy with ... more This work explores the combination of µ-Raman spectroscopy and scanning electron microscopy with X-ray energy dispersive spectrometry (SEM-EDS) for the study of the glazes in 15th-16th century Hispano-Moresque architectural tiles. These are high lead glazes that can be tin-opacified or transparent, and present five colors: tin-white, cobalt-blue, copper-green, iron-amber, and manganese-brown. They are generally homogenous and mineral inclusions are mostly concentrated in the glaze-ceramic interface. Through SEM-EDS, these inclusions were observed and chemically analyzed, whereas µ-Raman allowed their identification on a molecular level. K-feldspars, wollastonite and diopside were the most common compounds, as well as cassiterite agglomerates that render the glaze opaque. Malayaite was identified in green glazes, and andradite and magnesioferrite in amber glazes. Co-Ni-ferrites were identified in blue glazes, as well as Ni-Fe-olivines. Manganese-brown is the color where most compound...

Archaeometry

For the first time, Hispano-Moresque glazed tiles from Portuguese and Spanish collections were st... more For the first time, Hispano-Moresque glazed tiles from Portuguese and Spanish collections were studied together and compared. This work is included in a wider study tackling the technology of Hispano-Moresque tile production from several collections in the Iberian Peninsula. While showing many similarities, differences were identified between collections, regarding both chemical and morphological characteristics. The collection from Mosteiro de Santa Clara-a-† in memoriam of our co-author and dear friend V.S.F. Muralha Velha (Coimbra) stands out from the other collections, with higher SnO2 content (up to 14 %wt.), the highest Fe2O3 contents in amber glazes, and a Ca-rich interface layer (mostly comprised of wollastonite, CaSiO3). Samples from Palácio Nacional de Sintra (near Lisbon) and Sevilleattributed samples (from Instituto Valencia de Don Juan) are chemically similar, except that most Sintra's samples display a K-rich glaze-ceramic interface, whereas the ones from Seville exhibit both K-rich and Ca-rich inclusions. The samples attributed to Toledo show glazes with many inclusions, contrasting with the homogeneous glazes in most Hispano-Moresque tiles. From these results we identify differences that can be used as markers in future studies on Hispano-Moresque tiles.

Scientific Reports

An enigmatic chloride-rich iron (oxyhydr)oxide has been recently identified together with mercury... more An enigmatic chloride-rich iron (oxyhydr)oxide has been recently identified together with mercury anomalies in End-Cretaceous marine sediments coeval with the Deccan Traps eruptions. The mineral was observed in Bidart (France) and Gubbio (Italy), suggesting a widespread phenomenon. However, the exact nature and origin of this Cl-bearing mineral remained speculative. Here, we characterized the accurate composition and nanostructure of this chloride-rich phase by using micro-Raman spectroscopy, Transmission (TEM) and Scanning (SEM) Electron Microscopy on Focused Ion Beam foils. We also provide new evidence of its occurrence in Zumaia, a reference KPg section from Spain. Results confirm akaganéite (β-FeOOH) as the main phase, with chloride content of 3-5 atomic weight %. Akaganéite particles are constituted by the aggregation of nanorods of akaganéite. Internal structures contain empty spaces, suggesting formation in a low-density (atmospheric) environment. This new mineralogical evidence supports the hypothesis that the observed akaganéite was formed in the Deccan volcanic plume and was transported to the Atlantic and Tethysian realms through the stratosphere. Therefore, akaganéite provides a potential new sedimentary marker to identify the imprint of the Deccan eruptions in the stratigraphic record and is evidence of volcanic halogen degassing and its potential role for the Cretaceous-Tertiary mass extinction. Emission of sulphur and halogen species from continental flood basalt provinces are of particular interest due to their short-term impact on the environment and climate, and therefore their potential role in the triggering of Phanerozoic mass extinctions 1-3. Notably, sulfuric acid aerosol (H 2 SO 4), largely formed by the oxidation of magmatic sulfur dioxide (SO 2) in the atmosphere, is proposed to have resulted in widespread acid rains and surficial oceanic acidification leading to a major breakdown in the biological productivity and subsequent biotic crises 1. Another climatic forcing resulting from volcanogenic sulfur degassing is the formation of sulfate aerosols in the lower stratosphere, which would have induced tropospheric cooling due to the reduction of the solar energy flux reaching Earth's surface 4. Less attention has been given to halogen species, like hydrochloric acid (HCl), despite their potentially critical effect on ozone destruction and resulting climate change 5. This is partly because numerical models have suggested that halogen gases from explosive volcanoes are scavenged by aqueous phases before they reach the stratosphere, thus limiting their impact on the climate on a global/regional scale 6. Although measurements of halogens in the stratosphere after volcanic eruptions remain ambiguous, more recent modelling and in-situ/satellite HCl measurements of recent explosive volcanic eruptions, such as the Hekla and Soufrière Hills volcanoes, in 2000 and 2006, respectively, suggest that significant (at Hekla measurements suggest almost all HCl emitted reaches the stratosphere) amounts of HCl can penetrate into the stratosphere 7-10. In

Applied spectroscopy, 2017

This work is part of a broader research line that aims to develop and implement a nondestructive ... more This work is part of a broader research line that aims to develop and implement a nondestructive methodology for the chemical characterization of archaeological metals based on a protocol that combines energy dispersive X-ray fluorescence spectrometry (ED-XRF) with a Monte Carlo (MC) simulation algorithm. In this paper, the ED-XRF-MC protocol has been applied to estimate the chemical composition of a selected group of 26 copper-based artifacts and fragments recovered at Perdigões, one of the larger Chalcolithic sites of southwest Iberia. All the analyzed artifacts have a multilayered structure composed of the alloy substrate and of a superficial layer common in each metal buried for hundreds of years and consisting of the patina mixed with soil. Due to the difficulty in determining the quantitative composition of these alloys in the presence of this complex patina/encrustation layer, the spectrometric protocol applied in this paper allows to simulate and to determine the composition...

Journal of Raman Spectroscopy, 2017

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, Oct 13, 2016

A corrosion product rarely reported in the literature has been found on the copper support of thr... more A corrosion product rarely reported in the literature has been found on the copper support of three miniature paintings of the 17th and 18th centuries. This product, which has been identified as dicoppertrihydroxyformate (Cu2(OH)3HCOO), is an unusual basic copper formate found on copper artifacts. The identification and characterization of dicoppertrihydroxyformate was carried out directly over the corroded surface of the objects, using a nondestructive approach, which combines the integrated use of various microanalytical techniques. Using this approach, it was possible to obtain a set of new reference data about the natural form of Cu2(OH)3HCOO, that will enable its unambiguous identification in other similar objects. In this work, the probable causes that may have contributed to its formation are also discussed.

Conimbriga, 2015

Do conjunto de intervenções arqueológicas ocorridas na área urbana de Évora nos últimos trinta an... more Do conjunto de intervenções arqueológicas ocorridas na área urbana de Évora nos últimos trinta anos resultou um espólio cerâmico bastante significativo e heterogéneo de cronologia medieval-islâmica (entre os séculos VIII e XII). Neste espólio destaca-se uma tigela com uma técnica ornamental até agora nunca documentada na Península Ibérica. Ao expor e discutir os resultados do estudo estilístico e analítico efetuado sobre a peça, revelou-se a originalidade da técnica decorativa, caracterizada por uma cor de base castanho/castanho escuro sobre a qual está desenvolvida uma decoração em verde e branco. Este estudo pretende contribuir para um melhor conhecimento da cerâmica islâmica da Península Ibérica e, subsequentemente, do território português.

Materials Characterization, Jul 1, 2009

Evora Cathedral (one of the most emblematic monuments of Evora — Portugal) has suffered several c... more Evora Cathedral (one of the most emblematic monuments of Evora — Portugal) has suffered several conservation and restoration interventions through the ages, without, however, any type of previous knowledge about mortars and materials used. This work was carried out in order to identify the mortar&amp;amp;amp;amp;amp;amp;amp;amp;amp;#x27;s composition in different locations, which were attributed to different construction or conservation periods.The characterisation methodology

Apresentam-se os resultados de um estudo por espectroscopia de absorção de raios X (XANES) da des... more Apresentam-se os resultados de um estudo por espectroscopia de absorção de raios X (XANES) da descontinuidade K do enxofre em rochas vítreas (filões e escoadas) da ilha da Boavista (Cabo Verde). Esta técnica permite inferir os estados ou especiação do elemento, por comparação com espectros de compostos modelo. O vitrófiro de uma escoada apresenta o andamento característico do grupo sulfato, enquanto os espectros do material vítreo de filões indiciam a coexistência de diversos estados para o enxofre.

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Microchemical Journal, 2015

This study presents results on a developed methodology to characterize ground layers in Portugues... more This study presents results on a developed methodology to characterize ground layers in Portuguese workshops. In this work a set of altarpieces of the 15 th and 16 th centuries, assigned to Coimbra painting workshop was studied, overall the masters Vicente Gil (doc. Coimbra 1498-1525), Manuel Vicente (doc. Coimbra 1521-1530) and Bernardo Manuel (act. c. 1559-94), father, son and grandson, encompassing from late gothic to mannerist periods. The aim of the study is to compare ground layers, fillers and binders of Coimbra workshop, and to correlate their characteristics to understand the technical evolution of this family of painters, using complementary microscopic techniques. The cross-sections from the groups of paintings were examined by optical microscopy and the results were integrated through the analysis obtained by μ-X-ray diffraction, scanning electron microscopy with energy dispersive X-ray Spectrometry, μ-confocal Raman and occasionally with μ-Fourier transform infrared spectroscopy imaging. Ground layers are of calcium sulfate, present as gesso grosso (mainly anhydrite with small amounts of gypsum) in the first and last phases of the workshop and gesso mate (mainly gypsum with small amounts of anhydrite) in an intermediate period. Binders have protein and oleic characteristics.

Microchemical Journal, 2016

The micro-chemical/mineralogical composition of samples of grey-paste imitations of Italic Late R... more The micro-chemical/mineralogical composition of samples of grey-paste imitations of Italic Late Republican black gloss tableware displaying a particular kind of lozenge-shaped decoration ("Losanga pottery") from Portuguese and Spanish archaeological sites in SW Iberia has been analysed by BSEM + EDS, μXRD, Powder XRD, Portable XRF and μRaman spectroscopy. "Losanga" decorated ceramics have been found throughout the Western Mediterranean. Most of the sherds display a green-brown to greyish-black engobe at the surface resembling the gloss found in Attic pottery from Classical Greece. The overall chemical, mineralogical and fossiliferous homogeneities of the ceramic paste show common features (low K-feldspar/plagioclase ratio, high Ca content, abundance of well-preserved fragments of foraminifera microfossils) that indicate low firing conditions in the kiln ranging from 650 to 900°C. With respect to the ceramic body, analytical results confirm an enrichment in the surface gloss layer of iron, potassium and aluminium and a depletion in silicon and calcium; the very fine grain size of the surface coating suggests elutriation of iron oxide-rich clays as confirmed by the presence of magnetite, maghemite and goethite in μ-XRD scan. Chemical and mineralogical data also suggest that the firing process was performed in a 600-850°C temperature range, adopting the well-known technique of alternating oxidizing and reducing firing conditions largely employed at the time. The analytical results, while compatible with the archaeological hypothesis of a common provenance of the raw materials for pottery production from the Guadalquivir valley workshops cannot be considered conclusive due to the similarity in the geological substrate in the two SW Iberian regions under study.

This article presents the material and technological data obtained from the study of the preparat... more This article presents the material and technological data obtained from the study of the preparatory layers of 32 panel paintings produced in the Alentejo region, southern Portugal, and attributed to the painter Francisco João, active between 1563 and 1595. The investigation was based on the macroscopic observation of the paintings and on the analysis of the preparatory layers with several analytical methods. The grounds are white and composed of a single layer of "gesso grosso", mainly anhydrite mixed with a little calcium sulphate dihydrate, calcite and dolomite. The priming layers, found in six groups of paintings, are medium-rich and carry a few red (minium or vermilion) or ochre and brown (possibly umber) pigments. Non painted edges and barbs were found in the majority of paintings as well as the imprints of the tools used to spread and polish the preparatory layers.

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, 2015

Many conservation interventions have to consider the filling-gaps operation to remake missing par... more Many conservation interventions have to consider the filling-gaps operation to remake missing parts of original material and this is still an active topic of debate since it raises technical, aesthetical and ethical issues. A wide variety of materials have been used as fillers, usually in an empirical way, without much knowledge of their characteristics, compatibility and reversibility or even durability issues when applied to glazed ceramic tile (azulejo). In order to improve conservation actions it is necessary to understand the existing solutions to choose those that adapt best to the azulejo substrate and try to develop better formulations to fill the missing parts, either from the glaze or the ceramic body. To achieve better results in the future it would therefore be important to know the different solutions adopted in the past and evaluate the performance of these treatments through time. The compilation of information proved to be a difficult task either because the reports ...

In order to aid research, improve preservation actions and develop better options for future inte... more In order to aid research, improve preservation actions and develop better options for future interventions it is important to know the preservation materials and procedures adopted throughout the past and especially the ones being adopted nowadays. A survey to specialists working in situ in preservation and restoration of glazed decorative tiles has been performed aiming at getting insight on their type of training, work portfolio, opinions, the current materials and procedures used in the diverse phases of a preservation intervention (diagnosis, cleaning, consolidation, bonding fragments and fixing of glazed layer, volumetric and chromatic reintegration, final coating, resetting of tiles and manufacture of replicas) and the criteria/factors that support the specialists choices.