G. Vaggelli

Fragments of the Western Alpine Chain as Historic Ornamental Stones in Turin (Italy): Enhancement of Urban Geological Heritage through Geotourism

In Piemonte, stone has always been the most widely used raw material for buildings, characterizing the architectural identity of the city of Turin. All kinds of rocks, metamorphic, igneous, and sedimentary, are represented, including gneisses, marbles, granitoids, and, less commonly, limestones. The great variety of ornamental stones is clearly due to the highly composite geological nature of the Piemonte region related to the presence of the orogenic Alpine chain and the sedimentary Tertiary Piemonte Basin. This paper provides a representative list of the most historic ornamental stones of Piemonte, which have been used over the centuries in buildings and architecture. The main stones occurring in Turin have been identified and described from a petrographic and mineralogical point of view in order to find out the corresponding geological units and quarry sites, from which they were exploited. This allows the associated cultural and scientific interest of stones to be emphasized in the architecture of a town which lies between a mountain chain and a hilly region.

Mediaeval stained glasses of pisa cathedral (Italy): their composition and alteration products

X-ray microanalysis and infrared spectroscopic investigations of some coloured panes of the mediaeval stained-glass windows of Pisa Cathedral have provided information regarding their composition and alteration products. In particular, this study has revealed the existance of both potash and soda glasses, which were altered in two distinct ways. A comparison with a coeval glass belonging to a church in Bologna is reported.

Sulfur isotope evolution in sulfide ores from Western Alps: assessing the influence of subduction-related metamorphism

Sulfides entering subduction zones can play an important role in the release of sulfur and metals to the mantle wedge and contribute to the formation of volcanic arc-associated ores. Fractionation of stable sulfur isotopes recorded by sulfides during metamorphism can provide evidence of fluid-rock interactions during metamorphism and give insights on sulfur mobilization. A detailed microtextural and geochemical study was performed on mineralized samples from two ocean floor-related sulfide deposits (Servette and Beth-Ghinivert) in high-pressure units of the Italian Western Alps, which underwent different metamorphic evolutions. The combination of microtextural investigations with δ34S values from in situ ion probe analyses within individual pyrite and chalcopyrite grains allowed evaluation of the effectiveness of metamorphism in modifying the isotopic record and mobilizing sulfur and metals and have insights on fluid circulation within the slab. Textures and isotopic compositions inherited from the protolith are recorded at Beth-Ghinivert, where limited metamorphic recrystallization is attributed to limited interaction with metamorphic fluids. Isotopic modification by metamorphic processes occurred only at the submillimeter scale at Servette, where local interactions with infiltrating hydrothermal fluid are recorded by metamorphic grains. Notwithstanding the differences recorded by the two deposits, neither underwent intensive isotopic reequilibration or records evidence of intense fluid-rock interaction and S mobilization during metamorphism. Therefore, subducted sulfide deposits dominated by pyrite and chalcopyrite are unlikely to release significant quantities of sulfur to the mantle wedge and to arc magmatism sources at metamorphic grades below the lower eclogite facies.

µ-XRF Analysis of Trace Elements in Lapis Lazuli-Forming Minerals for a Provenance Study.

This paper presents new developments on the provenance study of lapis lazuli started by our group in 2008: during the years a multi-technique approach has been exploited to obtain minero-petrographic characterization and creation of a database considering only rock samples of known provenance. Since the final aim of the study is to develop a method to analyze archeological findings and artworks made with lapis lazuli in a completely non-invasive way, ion beam analysis techniques were employed to trace the provenance of the raw material used for the production of artifacts. Continuing this goal and focusing the analysis on determination of more significant minero-chemical markers for the provenance study of trace elements in different minerals, the method was extended with the use of micro X-ray fluorescence (µ-XRF), to test the potential of the technique for this application. The analyzes were focused on diopside and pyrite in lapis lazuli samples of known provenance (Afghanistan, Tajikistan, and Siberia). In addition, µ-XRF data were compared with micro proton-induced X-ray emission (µ-PIXE) results to verify the agreement between the two databases and to compare the analytical performance of both techniques for this application.

Compositional X-Ray Maps of Metamorphic and Magmatic Minerals

This paper deals with the applications of qualitative and quantitative x-ray compositional maps collected by either an energy-dispersive spectrometer (EDS) or a wavelength-dispersive spectrometer (WDS) on magmatic and metamorphic minerals.

The stones of the statuary of the Egyptian Museum of Torino (Italy): geologic and petrographic characterization

A geologic and petrographic study was performed on a rich collection of statues made of stone exposed at the statuary of the Egyptian Museum of Turin (NW Italy) to enhance the value of this artistic heritage and set the basis for its best conservation. Magmatic and sedimentary rocks were recognized. Magmatic rocks with an intrusive origin are the most represented and include two main varieties: Red Granite, consisting of a sieno-granite with porphyritic texture and pink to red K-feldspars, and Black Granite, which includes granodiorite, quartz diorite and tonalite lithotypes, whose colour ranges from grey to almost black. These magmatic rocks belong to the Arabian–Nubian shield, and the historical quarries are located near Aswan. The sedimentary rocks are represented by Cenozoic white limestones and red sandstones and Cretaceous dark-yellow Nubian sandstones. Finally, we note the occurrence of the so-called Bekhen Stone, originally attributed to a green-black metagreywacke belonging to the Hammamat series of late Precambrian age, outcropping in the central sector of the Eastern Desert, and re-interpreted here as a massive dark-green sandstone. This paper provides a scientific classification of the artefacts exposed in the statuary rooms based on the employed materials and contributes to the enhancement of the valuable collection of stone artefacts preserved in one of the leading ancient Egyptian Museums in the world.

The stones of the Egyptian Museum of Turin: geological, mineralogical and petrographical characterization

1. Dipartimento di Scienze della Terra Università degli Studi di Milano. 2. CNR Istituto di Cristallografia Sede di Bari. 3. Dipartimento di Scienze della Terra Università degli Studi di Torino. 4. CrisDi Interdepartmental Centre for the Research and Development of Crystallography – Torino. 5. Dipartimento di Scienze della Terra e dellAmbiente Università di Pavia. 6. Dipartimento di Geoscienze – Università degli Studi di Padova.Lucchi, Renata G. ... et. al.-- 87° Congresso della Societa Geologica Italiana e 90° Congresso della Societa Italiana di Mineralogia e Petrologia, The Future of the Italian Geosciences - The Italian Geosciences of the Future, 10-12 September 2014, Milan, Italy.-- 1 pageThe Montellina Spring (370 m a.s.l.) represents an example of groundwater resource in mountain region. It is a significant source of drinking water located in the right side of the Dora Baltea Valley (Northwestern Italy), SW of Quincinetto town. This spring shows a morphological location along a ridge, 400 m from the Renanchio Torrent in the lower sector of the slope. The spring was investigated using various methodologies as geological survey, supported by photo interpretation, structural reconstruction, NaCl and fluorescent tracer tests, discharge measurements. This multidisciplinary approach, necessary due to the complex geological setting, is required for the importance of the Montellina Spring. It is interesting in the hydrogeological context of Western Alps for its high discharge, relatively constant over time (average 150 l/s), and for its location outside a fluvial incision and suspended about 40 m above the Dora Baltea valley floor (Lasagna et al. 2013). According to the geological setting, the hydrogeological reconstruction of the area suggests that the large amount of groundwater in the basin is essentially favoured by a highly fractured bedrock, covered by wide and thick bodies of glacial and gravitational sediments. The emergence of the water along the slope, in the Montellina Spring, is essentially due to a change of permeability between the deep bedrock and the shallow bedrock and/or surficial sediments. The deep bedrock, showing closed fractures and/or fractures filled by glacial deposits, is slightly permeable. The shallow bedrock, strongly loosened as result of gravitational phenomena, and the local gravitational sediments are, on the contrary, highly permeable. The concentration of water at the spring is due to several reasons. a) The spring is immediately downward a detachment niche, dipping towards the spring, that essentially drains the water connected to the change of permeability in the bedrock. b) It is along an important fracture, that carries a part of the losses of the Renanchio Torrent. c) Finally, it is favored by the visible and buried morphology. Although it is located along a ridge, the spring occurs in a small depression between a moraine and a landslide body. It also can be favored by the likely concave trend of buried base of the landslide. At last, tracer tests of the Renanchio Torrent water with fluorescent tracer are performed, with a continuous monitoring in the Montellina Spring. The surveys permit to verify and quantify the spring and torrent hydrogeological relationship, suggesting that only a small fraction of stream losses feeds the spring.