Repositório RCAAP

Research has been carried out in Alto Ribatejo (central Portugal, western Iberia) with the purpose of contextualizing Late Pleistocene and Early Holocene archaeological remains within the coeval landscape. Several regional Quaternary deposits were analysed in terms of their sand fraction mineralogy (microscopic observation) and clay mineralogy (X-ray diffraction of orientated aggregates). The sedimentary record ascribed to the ~30-12 ka interval (Last Glacial and Tardi-glacial periods) is represented by colluviums and aeolian sands with predominance of illite. Illite is progressively replaced by vermiculite and some kaolinite or smectite in the upper stratigraphic levels of the Holocene deposits. The obtained data indicates cold and dry conditions during the Last Glacial/Tardi-glacial and a temperate climate in the Holocene.

A mixture of beeswax and Dammar resin (in a ratio of 7 parts to 2 parts, respectively) prepared as an adhesive, was profusely used for fixing water gilding and tempera coatings on polychrome sculptures, in Portugal, in the second half of the twentieth century. This practice was the result of a conservation technology transfer that took place throughout northern Europe, namely throughout education and training of young restorers from abroad at Institut Royal du Patrimoine Artistique in Brussels. This type of treatment was challenged in the 1970’s. This paper presents the methodology used (from an archaeological perspective) to find again these substances on sculptures which have been impregnated with them, and show until which point it is possible to detect both wax and resin in the paint layers. The results obtained by micro Fourier transform infrared spectroscopy, and Pyrolysis-Gas Chromatography-Mass Spectrometry proved difficult to put in evidence the presence of the Dammar resin; a limit which is not without consequences for the historic and conservation assessment of our heritage.

In the collection of the Fine Arts Museum of Seville there ar several artworks by anonymous Spanish painters from the 16th century. One of the most interesting among them is the Nativity altarpiece (around 1525) attributed to the Master of Moguer. The objective of the present research was to get information on painting materials applied by the artist. For this purpose, non-destructive analytical techniques have been used: exam with UV light and X-ray fluorescence. It was possible to identify the majority of the inorganic pigments used by the Master, all of them characteristic for that period of time: lead white (identified by the presence of Pb on XRF spectra), yellow and red ochres (Fe), lead-tin yellow (Pb, Sn), vermilion (Hg), a copper based green pigment (Cu) and azurite (Cu). The presence of Au confirmes the application of silver foil. In several areas of the panel later interventions have been confirmed on the bases of zinc white (Zn).

The pigments used by the Spanish costumbrism painter Pérez Jiménez (Segura de León, Badajoz, 1887-Oviedo, 1967) in some of his most representative paintings, have been characterized by a portable EDXRF. The paintings De vuelta de la Fuente (1908), El Ramito de Flores (1910), and Los Recién casados (1912), were analyzed and compared to a later work, Autorretrato (1938), in order to see de evolution of the artist palette. In this painting, a change in the white colour pigment has been found, which is in agreement with the date of it was made. Moreover, two of the paintings present restoration in different areas, which have been analyzed in order to compare with the original pigments. Some noteworthy differences have been found in both paintings, suggesting that a different restoration technique has been applied.

One of the major challenges in the conservation of cultural heritage is the prevention and control of contamination caused by microorganisms. The goals of the present study were the evaluation of methodologies for the characterization and quantification of the bioburden present in ancient ceramic tiles, and the estimation of the minimum dose of gamma radiation (Cobalt-60) necessary to inactivate the bioburden of these samples. Two ceramic tile panels were selected as case studies due to the evident signals of biodeterioration: the “Grande Panorama de Lisboa” (23 m length), of the beginning of the XVIII century, the most notable piece of the National Tile Museum and classified as National Treasure; and the panel “Quinta de Santo António” (XVIII century). The sampling, isolation and quantification of the bioburden present in the tiles were performed by the swab method followed by counting of colony forming units (CFU). The microorganisms isolated were phenotypically characterized by conventional techniques of microbiology in order to establish contamination patterns. Tile samples from the panel “Quinta de Santo António” were exposed to sub-lethal doses (1 to 4 kGy) of gamma radiation, and the bioburden of survival population evaluated both quantitatively and qualitatively. In the analyzed panels, the estimate bioburden varied between 102-103 CFU/100 cm2 of tile, consisting mostly of Gram positive rods (> 56%). The gamma rays irradiation indicated a decrease of the number of the microorganisms of approximately 25% for 4 kGy. However, the microbial load did not present an exponential inactivation kinetics. The obtained results suggest the potentiality of application of gamma radiation in the tile decontamination as a conservation treatment.

Neutron tomography (NT) setup installed at the Portuguese Nuclear Research Reactor (Sacavém, Portugal) 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. NT showed that brushing technique appears to be more efficient than immersion for the application of the consolidant Paraloid® B-72 inside tiles. After treatment and immersion in water, water remains more time between the glaze and the ceramic body.

Las cuevas y cavidades graníticas son medios geomorfológicos asociados a flujos de agua subterráneos con un marcado régimen turbulento ligado a la estacionalidad. Poco estudiados hasta el momento presentan un gran interés sedimentario, geomorfológico y a veces también arqueológico pues con frecuencia conservan restos de actividad humana (principalmente industria lítica y cerámicas) y mas raramente restos biológicos. Los restos cerámicos aparecen bien al descubierto o enterrados y se pueden caracterizar mineralógicamente y datar por termoluminiscencia (TL). La enérgica dinámica del agua justifica la erosión de los sedimentos y la extrema fracturación de los restos cerámicos que aparecen fracturados y dispersos. Este hecho dificulta su datación por las dimensiones de los fragmentos y por la desaparición del contexto sedimentario original lo que imposibilita el cálculo de la dosis anual de radiación recibida. En este trabajo se presentan los resultados de la datación y la estimación de edades de diversos fragmentos cerámicos procedentes de varias cuevas graníticas de Galicia. Las dataciones obtenidas van desde edades medievales (1 ka BP) a romanas o prerromanas (2 ka BP), calcolíticas (6 ka BP) y hasta del inicio del Neolítico (7 ka BP).    

Considering one of the methodological principles of Geology, one essays to discuss the possible interest of actualistic studies for the understanding of the alteration processes affecting the built heritage. Surfaces in the built environment might record overlaps of different events of one or more alteration causes and the complexity of causality relations might increase along time. The study of present occurrences of alteration processes allows a closer (in terms of time) observation of the effects of those processes. Recent built works are particularly interesting given the lesser overlap of events and possible existence of conditions that favour a better knowledge of both materials and decay agents. However, one needs to consider the possible limitation of the observation period in relation to the cycles of the processes and possible existence of differences between past and present conditions. Actualistic studies can also be useful in a prospective perspective to assess the evolution of the effects of the alteration processes along time.

Biological stone colonisation is one of the main problems related to the conservation of monuments and buildings. Stone biodeterioration has been assessed by several authors using time-consuming and extensive sampling methodologies for microbial identification and the follow-up of their action. However, most sampling procedures may convert the own researchers in deterioration agents. In this study the use of non-contact techniques for early detection and monitoring of microbial colonisations is proposed, as a contribution to the goal of the preservation of cultural heritage.

   

El fuego con frecuencia forma parte de la historia del deterioro de materiales pétreos en edificios. Es uno de los agentes de meteorización más catastróficos para los materiales pétreos, pero además puede ser el resultado de eventos históricos relevantes, como guerras. Conocer la máxima temperatura alcanzada por materiales pétreos durante un incendio es importante para comprender el daño posterior. En este trabajo se ha realizado un estudio en laboratorio para evaluar la máxima temperatura alcanzada en la superficie de materiales pétreos, debido a incendios en el pasado. Se ha medido la sensibilidad del cuarzo a diferentes temperaturas por medio de termoluminiscencia (TL ). La curva de TL del cuarzo muestra tres picos principales a 110, 200-210 y 250-400 ºC, cuya sensibilidad puede incrementarse si durante un fuego se alcanzan determinadas temperaturas. Midiendo los cambios de sensibilidad de esos picos, pueden calcularse las máximas temperaturas alcanzadas. Para los testes se ha seleccionado la arenisca de “Un castillo” (Zaragoza, España), usada de forma continuada desde tiempos Romanos en el área de Zaragoza. Se han tomado probetas cúbicas de 5 cm de lado y se han calentado a temperaturas desde 200 ºC hasta 700 ºC.  

The construction of a database which allows compiling, organizing and making available to the scientific community, the absolute dates published, is an important tool in archaeological research. Specifically designed and engineered for this purpose, the database for the Absolute Dates of the Iberian Peninsula (DAPI), includes the results collected from different dating methods available to the archaeological sites of the Iberian Peninsula. This database was designed in Access, a program released worldwide and with a simple interface, while still allowing exporting to Excel, simplifying the visualization of data. Its interface allows the user to view the data already entered by archaeological site or by printing the list of existing dates; view in Google Earth, the geographic location of the site; enables the insertion of new data or even change any erroneous data.

800 páginas

Carlos Ribeiro (1813-1882) teve, como geólogo e arqueólogo, um intenso e recorrente contacto com o território Oeirense. Ao proceder ao reconhecimento geológico dos arredores da capital, trabalho realizado em diversas ocasiões e que em parte se relacionou com abastecimento de água a Lisboa, trabalhos de que existe registo desde a década de 1850 até à de 1870, cartografou os afloramentos geológicos de diversas épocas que ocupam este tracto de terreno, representados na Carta Geológica de Portugal na escala de 1/500 000, em co-autoria com J. F. Nery Delgado, seu adjunto na Secção dos Trabalhos Geológicos, cuja primeira edição data de 1876, logo seguida de segunda edição, dois anos volvidos. No decurso desses levantamentos geológicos, identificou duas estações arqueológicas de grande relevância no território concelhio: o povoado pré-histórico de Leceia e a necrópole da gruta natural da Ponte da Lage, na margem esquerda da ribeira de Lage, fronteira à povoação do mesmo nome.

O duplo centenário do nascimento do académico Carlos Ribeiro não passou estranhamente despercebido. Coronel, não se terá distinguido na carreira das armas, mas no campo da ciência ganhou renome, como antropólogo, arqueólogo e geólogo.

O manuscrito que agora se publica, intitulado “Breve noticia do terreno quaternario de Portugal” encontrava-se até agora inédito, apresentando-se a sua transcrição integral no final deste estudo. Corresponde à segunda parte da monografia publicada por Carlos Ribeiro em 1866, dedicada à caracterização geológica dos, por ele considerados, terrenos quaternários das bacias sedimentares do Tejo e do Sado, incluindo espólios e estações arqueológicas correlativas, sumariamente mencionadas por Carlos Ribeiro, designadamente as produções atribuídas ao Homem terciário, as quais serão adiante abordadas, e os concheiros mesolíticos das ribeiras de Magos e de Muge.

As questões científicas suscitadas pelas investigações conduzidas por Carlos Ribeiro nos concheiros de Muge, que descobriu e escavou, assumiram um papel de primeira importância na época, não só pela importância excepcional intrínseca das próprias estações, mas também pelos problemas que os resultados obtidos, tanto arqueológicos como antropológicos suscitaram, vindo a ocupar outros investigadores, não menos informados, ao longo de todo o século XX, projectando-se, com outros protagonistas e outras metodologias e recursos, na actualidade.

Deixamos aqui exaradas as opiniões e comentários possíveis em face da análise de um documento que de todo não parece ter estado pronto para o prelo. É antes um simples rascunho, sem ordem clara de subdivisões nem critério estabelecido, transcrito de um manuscrito onde nem todas as palavras puderam ser decifradas. De certo modo, corresponde a um desenvolvimento da memória sobre o Solo Quaternário, limitada às bacias hidrográficas do Tejo e Sado.

Como abastecer de água a cidade de Lisboa? Com água subterrânea de nascente ou com água superficial captada por galerias filtrantes no rio Tejo? A estas e a outras questões relacionadas procurou responder Carlos Ribeiro por incumbência governamental nas décadas de 50 e 60 do século 19. Em 1857, Carlos Ribeiro foi chamado a fazer o reconhecimento geológico e hidrogeológico dos terrenos das vizinhanças de Lisboa, com o objectivo de avaliar as fontes disponíveis para abastecimento à cidade. Desenvolveu um trabalho minucioso e importante, que justificou a sua apresentação à Academia Real das Ciências e a publicação, em secções, nos Annaes das Sciencias e Lettras da mesma Academia, em 1857 e 1858.

Ao lado da sua carreira militar vai desenvolvendo uma linha de actividades técnico-científicas ligada ao domínio geo-mineiro. Inicia esta actividade cedo, por 1840. E neste campo, aquele que nos interessa considerar, agora, duas constantes emergem: o intenso trabalho de campo, suportado por conhecimentos de geologia regional imprescindíveis para o adequado enquadramento dos seus estudos e projectos mineiros e a procura de ligação ao conhecimento geo-mineiro internacional já que no país era domínio praticamente por desbravar.