Natalia Rovella

Cappadocian ignimbrite cave churches: stone degradation and conservation strategies

The focus of this research is to investigate the minero-petrographic features and the conservation aspects of the stone materials from some rock-hewn churches in Cappadocia region (Turkey) in order to choose the most appropriate consolidating systems to improve the resistance against the weathering and degradation phenomena of this unique world heritage site. In this study, specimens from the Tokali church in the Goreme’s Open Air Museum, and from the Forty Martyrs Church in Şahinefendi were analysed by optical microscopy and X-ray diffraction in order to examine the properties of the rock and especially how well preserved it is. The ignimbrite samples show a porphyritic structure with vitrophyric groundmass and crystalloclastic-vitrophyric texture. The presence of smectite and illite caused serious damage to the rock structure such as cracks, decohesion, exfoliation, and disaggregation phenomena.The consolidation tests were performed on the ignimbrite specimens, sized according to the standard procedure, by using three commercial silica-based products: NanoEstel, Estel 1000, and Estel 1100. The consolidant penetration was investigated by titanium labelling procedure followed by scanning electron microscopy–energy dispersive spectroscopy analysis. Colour measurements were used to study the possible chromatic changes due to the treatments. The capillary test was performed to evaluate the amount of water absorbed by the stone surfaces before and after the consolidating treatments. Lastly, the surface cohesion due to the consolidation was investigated by using the peeling test carried out on untreated and treated samples.The consolidating tests showed that the solvent-based products (Estel 1000, Estel 1100) exhibit a better distribution than the aqueous suspensions (NanoEstel). Nevertheless NanoEstel gives better results in the capillary absorption test, suggesting that this product has the ability to leave the stone porous structure substantially unaltered.

Modelling seasonal variations of natural radioactivity in soils: A case study in southern Italy

The activity of natural radionuclides in soil has become an environmental concern for local public and national authorities because of the harmful effects of radiation exposure on human health. In this context, modelling and mapping the activity of natural radionuclides in soil is an important research topic. The study was aimed to model, in a spatial sense, the soil radioactivity in an urban and peri-urban soils area in southern Italy to analyse the seasonal influence on soil radioactivity. Measures of gamma radiation naturally emitted through the decay of radioactive isotopes (potassium, uranium and thorium) were analysed using a geostatistical approach to map the spatial distribution of soil radioactivity. The activity of three radionuclides was measured at 181 locations using a high-resolution ?-ray spectrometry. To take into account the influence of season, the measurements were carried out in summer and in winter. Activity data were analysed by using a geostatistical approach and zones of relatively high or low radioactivity were delineated. Among the main processes which influence natural radioactivity such as geology, geochemical, pedological, and ecological processes, results of this study showed a prominent control of radio-emission measurements by seasonal changes. Low natural radioactivity levels were measured in December associated with winter weather and moist soil conditions (due to high rainfall and low temperature), and higher activity values in July, when the soil was dry and no precipitations occurred.

The colors of the Fontana di Trevi: an analytical approach

ABSTRACT During the last restoration of the Fontana di Trevi -Rome (2014–2015), it has been performed a diagnostic investigation to characterize the materials used to build and obtain the colors of the surfaces of some architectural elements of this fountain. According to the restoration teamwork needs, we focussed our efforts on the dome over the central statue of Oceanus, on the bas-relieves on the sides of the dome, and on the cliff where the water flows. Several samples were collected from these elements and therefore, they were subjected to an analytical approach including infrared spectroscopy, optical and scanning electron microscopy. The achieved results indicated the use of red earth pigments on the dome. The same pigment has been revealed on the bas-relieves, although their colors have an additional contribution due to degraded layers. Samples taken from the cliff showed a complex stratigraphy, although a white scialbo has been identified as original layer, testifying the intentions of the authors in term of color rendering. This information was essential for the restores in order to choose the proper intervention procedure for each investigated surface. The research testified the importance of an integrated diagnostic analysis to preserve the original colours of monuments and building.

Geology and conservation of cultural heritage: the study case of the Forty Martyrs rupestrian church in Şahinefendi area (Cappadocia, Turkey)

Cappadocian region is an unique ignimbrite landscape created by Neogenic volcanic activity and moulded by tectonics, climate and relative phenomena as erosion and freeze-thaw cycles. The earth pyramids represent the typical morphostructures produced by erosion in this context; here they are called Fairy Chimneys and are famous for hosting, from the Palaeolithic age, the population of the area, in particular the first Christian monastic communities and their painted rupestrian churches. Nevertheless the same environmental and geological context that in the past promoted the development of these structures, nowadays risks to threaten their conservation. The work is focused on the reconstruction of the geological and stratigraphic setting of the Forty Martyrs church area a typical rupestrian monastic settlement and the identification of critical elements threatening the structure in the time.

Evaluation of the consolidant efficiency of nanosilica based products on Neapolitan Yellow Tuff

The consolidation of stone materials used in the Cultural Heritage represents a critical issue because of their restoration and conservation. In this regard, Yellow Neapolitan Tuff is not only one of the most used rock but also one of the most affected by degradation phenomena. For this reason, it needs to individuate suitable strategies to preserve efficaciously this material. The consolidant efficiency of innovative nano-silica products was tested in this paper to evaluate their possible use in the conservation of stones employed in Cultural Heritage. The mixtures realized with tuff fragments and consolidants as binder at different concentrations were undergone peeling and point load tests. The results achieved exhibit the suitability of nanosilica products as consolidant in the tuff, suggesting their possible next use in the preservation of stone materials employed in Cultural Heritage.