Silvana Maria Grillo

The Mezza Spiaggia Tower (Cagliari, Italy): The Dating of Structures by the Metrological–Chronological Analysis of Masonry and the Petro-Geochemical Stratigraphy of Building Materials

This study is part of a more extensive research aimed at examining a number of important defence towers in and around Cagliari, Sardinia, Italy. These towers form part of Sardinia’s historic coastal defence system, dating to a period between the early sixteenth and the late seventeenth century (Fois 1981; Montaldo 1992; Pillosu 1957; Russo 1992). These historically and architecturally distinctive towers were originally built for defence purposes; however, since the nineteenth century when they no longer performed this function, they have declined into disuse and abandonment.

Polymetallic assemblages with precious metal tellurides and sulfosalts from the Furtei epithermal Au deposit, Sardinia, Italy: Paragenesis and genetic significance

Ore bodies of the Furtei epithermal gold deposit, W Sardinia, are highly enriched in telluride minerals. The association of hessite, stutzite, sylvanite, petzite, coloradoite, altaite, with native tellurium indicates direct magmatic inputs to the mineralizing solutions: a transition of this magmatic hydrothermal system from porphyry to high sulfidation epithermal mineralization environments is envisaged. Sulfidation states of telluride bearing ore fluids fluctuated between IS and HS conditions within the same mineralization, with telluride minerals related to both HS and IS assemblages. On the basis of available corroborative electron microprobe data on the telluride-rich parts of drillcore samples, the relationship between mineral assemblages and sulfidation states of fluids is assessed.

Rosa Beta granite (Sardinian Pink Granite): a heritage stone of international significance from Italy

Abstract ‘Rosa Beta’ or ‘Sardinian Pink granite’, an Hercynian granitoid from the Italian island of Sardinia, is formally here nominated as a Global Heritage Stone Resource. Rosa Beta is sourced from the Gallura region of northern Sardinia and has been associated with human heritage since prehistoric times. Notably it can be found in construction ranging from prehistoric Tomba dei Giganti, the 1st century Pantheon in Rome and the Renaissance Cathedral in Pisa to early 20th century monuments in Brazil and Egypt. Most importantly, it has also been used very extensively in the late 20th century for significant construction in countries as wide ranging as the USA, Saudi Arabia, Hong Kong, Singapore and Australia.

The Medieval San Francesco Convent in Cagliari: From the Architectural, Materical and Historical-Stratigraphical Analysis to the Information System

The Franciscan monastery, situated in the historic center of Cagliari (Sardinia), was founded in the thirteenth century, and transformed during the later centuries, up to the present day. The complexity of the case and the lack of objective data about its history has led us to carry out an interdisciplinary inquiry, in order to achieve a better knowledge of the building, preliminary for the drafting of a restoration project that respects all the signs that the time left. Starting from a deep examination of the indirect sources, turned out to be incomplete, the investigation continued with the execution of a survey with laser scanner and with the characterization of materials and related diseases of degradation.For the laser scanner survey we used a Faro Focus 3D, versatile and lightweight instrument that allows to perform scans with high speed point acquisition and high accuracy. For data elaboration we used the JRC 3D Reconstructor Software by the Gexcel srl.The characterization of the materials was perf...

Traditional Masonry Techniques and Characterization of Materials: The Mezzaspiaggia Tower (Cagliari, Sardinia)

The objects of this study are some towers situated in the geographical area of Cagliari, belonging to the Sardinia coastal defense system realized between the 16th and the beginning of the seventeenth century. This architectural organization, very rich and articulated, is full of historical and cultural significance, being the expression of traditional human activities. Even so, it is actually in a progressive state of degradation, having lost, since nineteenth century, a role in our society. Starting with this preamble, that is, with the purpose of warranting better preservation and management of similar cultural heritage examples, this article illustrates the results of an in-depth analysis concerning the above mentioned structures, following an interdisciplinary approach. Specifically, the research has been carried out integrating historical-archaeometric methodologies with mineralogical-petrographic as well as geochemical methods.

Sardinian Basalt—an Ancient Georesource Still En Vogue

Commercial basalt that is quarried in Sardinia is a natural resource which is the result of extensive volcanic activity during the Pliocene and Pleistocene ages, following the opening of the Campidano plain and Tyrrhenian Sea rift, when large volumes of basalt and andesite rock naturally moulded extensive areas of the Island. An example is provided by the “Giare” tablelands and several other large plateaus located in central Sardinia. Basalt has formed in many other areas of the Island, where a vast array of monuments dating back to the II–I millennium B.C. document the high workability, durability, and withstanding to weathering of basalt. The complex of circular defensive towers, known as “Su Nuraxi di Barumini” was included in the World Heritage List by UNESCO in 1997. Basalt is currently produced locally, and it is used for architectural and ornamental purposes. It is quarried from stone deposits or mined from huge boulders which are mechanically moved and sawn and then transported and manufactured in plants which are located in various sites throughout the Island. The paper begins with a historical introduction and then focusses on the current state-of-the-art of Sardinian basalt quarrying, processing, and usage. An analysis of the basalt market has been carried out.

Measure and material of the 18th- 20th century masonry techniques. Archaeological analysis of the University building in Cagliari (Italy)

The University building represents a valid benchmark of the 18th century civil architecture in Cagliari. It consists of two separate architectures, initially seat of the Rectorate and of the Tridentine seminary, which over time have taken on a homogeneous character. The research, facilitated by the realization of a recent restoration project, was aimed to examine the masonry techniques that characterize the building, following an interdisciplinary approach by means of archaeological analyses. The investigation consisted of two main phases, indirect and direct, carried out in parallel. Specifically, it has been based on a thorough survey of the masonries and on mineralogical and petrographic characterization of the natural and artificial stone materials. The data obtained directly and through experiments were compared with the information found in the archival sources related to the construction phases. In the context of reference, the contribution is significant to facilitate the recognition, the dating, and the preservation of coeval architectures that, unlike the one examined, are not philologically dated.

REE MOBILIZATION IN COMPLEX HYDROTHERMAL-METASOMATIC SYSTEMS: FLUID CHEMISTRY EVIDENCE OF ALBITITE AND CHLORITE-TALC MINERALISATIONS IN CENTRAL SARDINIA,ITALY

Several Na-feldspar and talc-chlorite deposits occur in central Sardinia. The development of post-magmatic Na-metasomatism mainly involved the bulk of the local plutons to which economic occurrences of metasomatic chlorite-talc are also associated. REE-bearing minerals have been found in the unaltered granodiorites, while different amounts of REE were redistributed in secondary phases in albitites during metasomatism. REE-bearing minerals are strongly depleted in chloritized rocks. Lanthanides may be mobilized under hydrothermal activity depending upon physicochemical conditions in the fluid phase. Among ligands, carbonates appear to have increased the solubility of REE somewhat but chlorine complexes may have played the major role in the REEdepletion of granites. However, other competing complexes can attain importance where their concentrations are somewhat anomalous. Preliminary analytical results for the investigated fluids appeal to an extensive leaching of REE by highly saline, halogen-rich solutions with the most striking features being the high contents of bromine.

The Roman Bridge of Sant’antioco (Sardinia, Italy): The Analysis of Masonries and Characterization of Materials

This article is part of an ongoing study dealing with the analysis of the bridge of the ancient city of Sant’Antioco. It is an architectural specialty dating back most probably to Roman times followed by many other interventions during the following centuries, and represents a piece of art of a unique road net of its kind, both for its function in connecting not only the opposite banks of a river but also a small island with the dry land. Additionally, its architectural design does not have any analogies in other similar designs. It has been studied following an interdisciplinary approach, with the aim of combining the architectural-constructive knowledge with methods used in geologic and geochemical investigations. Specifically, the purpose of this research is to gain a deeper understanding of the architectural elements under investigation, which is essential for correct and qualified restoration and conservation.

The Discovery of a New Metallogenic Province in Sardinia (Italy): Au–Ag Mineralisations of Tertiary Age

The Oligo–Miocene volcanic cycle was accompanied by intense hydrothermal phenomena, which produced extensive alteration zones and ore deposition, mostly of precious metals. The low price of gold before the seventies prevented any considerations for these occurrences. The worldwide development of studies concerning volcanic-related deposits caused renewed interest in this kind of epithermal mineralizations in the island and a prospecting program was developed in the eighties. A series of field surveys showed that hydrothermal alteration halos are widespread in the volcanic terrains, and Au–Ag bearing mineralised outcrops were detected in a few localities. An exploration program was performed which reached the ore evaluation stage in two areas. At present the Furtei mine is currently the only high sulfidation gold mine in Europe, while soil sampling confirmed that the Osilo area offer potential for low sulfidation precious metal occurrences. Several other precious metal indications will be explored in the near future.