1,720,982 research outputs found
Alteration patterns of marble and stones from different environment exposures: a systematic approach from buildings and museum collections in Genoa (Italy).
No full textMethodological Approach to Reconstructing Lost Monuments from Archaeological Findings: The San Francesco di Castelletto Church in Genoa
No full textThroughout history, natural hazards, wars, political changes and urban evolution have contributed to the obliteration of outstanding monuments. The study of their remains, frequently recovered as archaeological findings, can be the basis for a reconstruction of the lost structures, by way of their size, function, decoration and stylistic evolution. The present study developed a multidisciplinary approach to gather and interpret archaeological fragments and archive sources, in order to gain as much information as possible on “lost monuments”. The approach was tested with remnants (i.e., several hundreds of marble fragments found during archaeological excavations) of the monastic complex of San Francesco di Castelletto (Genoa), which was demolished after the Napoleonic suppressions. A preliminary organisation of the sample set was attained through cataloguing shape, size, and decoration. After this, a comparison with similar complexes still existing in Genoa allowed the inference of the age and specific ornamental functions for the majority of the pieces. Surface analysis, carried out in situ (portable microscope) and on micro-samples (petrographic analysis and SEM-EDS), allowed the characterisation of the materials (e.g., assessing marble provenance and identifying pigments). As a whole, the method evolved into an operational protocol, which helped both the organisation of the archaeological findings and the reconstruction of unknown phases of the lost monument
Alteration patterns of marble under different environmental exposures: a systematic approach from the Staglieno Monumental Cemetery and Museum Collections in Genoa (Italy).
No full textNon-invasive analytical technique to address water uptake on stone surfaces: The implemented Contact Sponge Method (i-CSM)
No full textThe assessment of capillary rise rate is a recommended test in Cultural Heritage diagnostics to evaluate the evolution of stone textural properties and decay, and performances of conservation treatments. Beside laboratory tests, diverse non-invasive and non-destructive, in-situ methods were developed in order to establish the monitoring for monumental structures and decorative apparatus: Karsten tube, Mirowsky pipe and contact sponge methods (CSM). The comparison between the diverse techniques demonstrated high comparability between the datasets obtained with the CSM (UNI 11432:2011) and those recast with capillary absorption. However, the dataset collected with the conventional method is affected by high standard deviation due to several variables, mainly operator-dependent. The adoption of a pocket penetrometer, coupled with the use of a thicker sponge, aimed at parameterizing the load upon the surface. The implementations allowed a higher reproducibility of the measures, as well as the possibility of applying increasing pressures. In this study the i(mplemented)-CSM was adopted to test the adsorption behaviour of a set of ornamental stones (Macigno Sandstone, Breccia Aurora, Rosso Verona and Vicenza Stone) both un-weathered and weathered by freeze-thaw ageing and salt weathering. A correlation between the maximum open pore radius and an increase in water absorbance at higher loads was established. The preliminary promising results wait to be further validated on larger datasets
Archaeometric and archaeological characterization of Medieval and post-Medieval tiles from S. Francesco’s church, Savona (Italy)
No full textA set of ceramic materials - about 270 pieces, mainly consisting of bricks and tiles (terracotta and glazed ceramics) largely fragmented - was found during recent restorations under the flooring of a room overlooking the cloister of S. Francesco’s church in Savona. The fragments were dispersed in the filling between an airspace structure of bricks and the current floor. These loose materials form an unusual archaeological layer, whose precise chronological and stratigraphic data are lacking. However, as the history of the monastic building and of the examined room is rather complex and poorly known, the ceramic materials were analysed in order to acquire information on the architectonic phases through material data.
At macroscopic scale the fragments showed typological and dimensional variability, thus were divided in groups with homogeneous characteristics. A representative sample of each group was analysed by optical microscopy (OM) and scanning electron microscopy (SEM) to obtain a full compositional and technological characterization. The analyses were aimed at identifying the provenance of the samples, and distinguishing different groups possibly to be related to different chronologies.
Petrographic analyses of the fabrics allowed identifying the local production, as suggested by the presence of: gneiss and amphibolite inclusions to be related to the local Palaeozoic basement, and calcareous (foraminifera) and siliceous (diatoms, radiolarians, sponge spiculae) microfossils associated with the Pliocene marine sediments outcropping in the area of Savona. The presence, on the majority of the pieces, of the so-called graida (grid) a feature typical of the tile production of Savona (i.e., a sort of stamp on the back of the tile to ensure higher adhesion to the mortar), concurs with the geological markers in identifying as local provenance. The OM observations allowed inferring: firing temperatures of approximately between 800°- 900°C (partial decomposition of carbonates, partial vitrification of the clay matrix and dehydration of micas), and for the glazed tiles a good technical level (double firing, no residual inclusions or bubbles). Unfortunately the lack of data for uncoated terracotta tiles in the area of Savona made it difficult to find
temporal constraints, e.g., through mensiochronological datasets. Only for some of the groups ante and post quem terms were established based on the correlation between the acquired dataset and bibliographical references. For example a group of green glazed square tiles has been dated to the end of XIII century, while a group of uncoated ceramics with a refined paste was dated to the XVI century based on archaeological evidences.
On the whole, the study allowed organizing the findings, characterizing the manufacturing process (provenance and firing techniques), and formulating hypothesis on the temporal evolution of the flooring of the room (i.e., at least 3 different paving between XIII - XVI century)
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