Maria Pia Riccardi

An approach to the dynamics of clay firing

Abstract Results of a detailed study on microtextural and microchemical characteristics of pottery obtained during different experimental firing runs carried out at different temperature under oxidising conditions are reported. During firing, the reaction behaviour of temper grains and clay matrix is dominated by disequilibrium conditions and characterised by the presence of different reacting sub-systems. Each one of them is compositionally well established and corresponds to different mineral phases in mutual contact. Reactions occur following the two main mechanisms: (i) reactions leading to nucleation and growth of new mineral phases (modal reactions) and (ii) reactions producing only compositional variations of phases (cryptic reactions). Modal reactions are given by new phases rimming the temper grains, whereas the cryptic reactions may develop during the partial transformation of a single phase, producing compositional zonings. Kinetic aspects are also considered in order to asses the role exerted by temperature, by bulk and mineral compositions and by fluid phase on the attainment of modal or cryptic reactions during firing.

Thermal, microscopic and X-ray diffraction studies on some ancient mortars

Within the framework of research on ancient mortars in Pavia and its district, thermal, microscopic, and X-ray diffraction measurements have been carried out on some mortar samples taken from three walls situated in the historical center of the city, and belonging to the following periods: 4‐6th, 9‐10th and the 16th centuries. A careful mineralogical and grain-size analysis showed that local raw materials were regularly used during the Middle Ages. By means of thermal analysis and thermogravimetry it was proved that the Roman age and medieval mortars are richer in calcite, whereas the presence of gypsum and dolomite are indicative of a poorer original composition or of compositional changes induced by atmospheric pollution in the mortars of the 16th century. # 1998 Elsevier Science B.V.

Devitrification kinetics of PbGeO3

The devitrification of glassy PbGeO3 was studied and interpreted by means of isothermal and non-isothermal Johnson-Mehl-Avrami equations. In the case of the non-isothermal approach, several approximated equations proposed by various authors were considered in order to obtain both the activation energy Ea and the Avrami morphological coefficient n of the crystallisation process. A critical discussion of the Avrami coefficient on the basis of experimental morphological evidence is also presented.

Powder diffraction of yellow and red natural earths from Lessini Mountains in NE Italy

Powder diffraction of yellow and red natural earths from Lessini Mountains in NE Italy Giovanni Cavallo, Maria Pia Riccardi, and Roberto Zorzin Department of Earth and Environmental Sciences, University of Pavia, via Ferrata 1, 27100 Pavia, Italy Institute of Materials and Constructions, University of Applied Sciences and Arts – Supsi, Campus Trevano, 6952 Canobbio, Switzerland Civic Museum of Natural History, Lungadige Porta Vittoria, 9, 37129 Verona, Italy

The Neolithic pottery of Abri Pendimoun (Castellar, France): a petro-archaeometric study

Abstract Middle and Late Neolithic ceramics from Abri Pendimoun (Castellar, France) and their geological raw materials have been investigated to characterize the ceramic bodies and to determine the possible provenance of raw materials. Petrographic, mineralogical and energy-dispersive spectrometry analyses were undertaken to define the compositional parameters of sherds and to clarify the relationship between Square Mouthed Pottery-phase I (VBQ I) and Chassey Culture. The ceramic bodies were generally made from glauconite-rich layers and terra rossa, unprocessed or mixed in variable proportions. Different kinds of temper, such as carbonates and/or aplite fragments, were added to the mixtures. Although most of the analysed ceramics were produced locally, a few mixtures show the addition of exogenous rocks. Although these ceramics could be interpreted as imported, we demonstrate that local clayey materials were used at Abri Pendimoun. The hypothesis that pottery was imported can therefore be ruled out. A small amount of crushed calcite (5%) was added to some glauconitic pellet mixtures. Pots made with this mixture are normally referred to the VBQ I. This combination of mixture and shape indicates that there was an important link between the VBQ I and Chassey Cultures.

Technological features of the ‘Cotto Variegato’: a petrological approach

Abstract The ‘Cotto Variegato’ are tiles used in Lombardy, between the XVII and XIX centuries as flooring for several historical buildings. Tiles are produced by the processing of two compositionally distinct clays. The main stylistic character of these tiles is a banded texture producing a veined aspect, in which white and red bands are also folded. The artefacts were hand crafted using two clayey raw materials of different composition, that are only partially mixed before the firing. The colour differences are produced during the firing. In all samples white and red portions are always composed of Ca-rich and Ca-poor clay, respectively. The multi-layered texture was obtained by a multiple folding and pressing process of the mixture. The interference of fold limbs with the tile surface gives the ‘variegato’ style to tiles. The paper explains how basic petrological knowledge can be applied to the study of ceramic artefacts in order to define provenance of the raw material, firing technology and how ancient craftsmen transformed the natural clayey materials into floor tiles. The methodological approach is that commonly applied to the study of the rocks and consists of textural analyses, at a different observational scale, combined with X-ray powder diffraction, X-ray fluorescence and microprobe analyses.

The life cycle approach as an innovative methodology for the recovery and restoration of cultural heritage

Purpose – In this paper, of exploratory character, the purpose of this paper is to propose the analysis of the life cycle for assessing the environmental, economic, and social impact in the activity of recovery, restoration, and valorization of Cultural Heritage. Design/methodology/approach – The analysis protocol is applied to the case of recovery and restoration processes and then outlining the salient features of what may become a model of Cultural Heritage Life Cycle Management (CH-LCM). Findings – The authors propose the approach of the life cycle, normally used to assess the impact of materials, processes or products, to the management of cultural heritage as an innovative methodology with great potential. Originality/value – The methodology for this sector is highly innovative, especially in its interdisciplinary approach, through the use of different technical, historical, and economic skills which can provide the tools for the preparation of a management plan according to the logic of the life cycle.

Sponsorship and patronage and beyond: PPP as an innovative practice in the management of cultural heritage

Purpose The purpose of this paper is to present alternative management practice methods for the cultural heritage sector apart from the traditional public support model. These alternatives rely on sponsorship and patronage as well as the newer and more innovative public-private partnership (PPP). Design/methodology/approach The paper is organized in two conceptual sections based on a literature review. The first section presents and compares two closely associated business strategy forms that are increasingly becoming popular within companies: sponsorship and patronage. These strategies are analyzed to show their advantages and disadvantages and are assessed based on their best uses in terms of the benefits from their implementation to all stakeholders involved (benefactors, recipients and the public) and, more particularly, to the benefactor’s company communication policy. The second section analyzes the PPP as a newer innovative practice in the cultural heritage sector, a recent development that has great potential, especially during an economic crisis where public funds are reduced, which risks the future recovery and proper maintenance of sites. Findings In the paper, the authors stressed that sponsorship, patronage and PPP are not merely alternative ways of primarily obtaining government funding for the cultural heritage sector but are also new strategic management practices that, when properly performed, will not only preserve and improve the sector but also allow more value to be distributed among all stakeholders. Originality/value Although the topic of PPP is treated fairly in the scientific literature, especially with regard to infrastructure, there are few cases of the application of this model to cultural heritage management.

Fluid rock interactions as recorded by Cl-rich amphiboles from continental and oceanic crust of italian orogenic belts.

A number of samples of Cl-rich amphiboles coming from oceanic and sub-continental gabbro bodies has been studied in order to compare their microstructural and compositional peculiarities and to investigate the fluid-rock interactions in different geodynamic contexts. The development of a first group of amphiboles outcropping in the Northern Apennines was the result of an hydration event that has been ascribed to oceanic metamorphism. The second group was found in a slice of continental crust subducted during Alpine collision, in a subcontinental metagabbro from the Sesia-Lanzo Zone of Western Italian Alps. Their development has been ascribed to a hydrothermal event that took place after the exhumation of the metagabbro during pre-Alpine lithospheric extension. The Cl-amphiboles are either found in veins, as granoblastic aggregates in different microstructures or as rims of zoned amphiboles, where brown-amphibole cores (sometimes Ti-rich), and successive green amphibole, are rimmed by the Cl-rich amphibole. All amphiboles show edembergite to pargasite compositions up to glaucophane and crossites when reequilibrated under HP conditions, with a direct correlation between Fe and Na (A) vs. Cl content, and inverse correlation of Mg and Na (M4) vs. Cl. A comparison with other Cl-amphiboles that have been observed both in oceanic and continental settings, allow inferring the role played by Cl-rich fluids infiltration both in oceanic and continental crust, during lithospheric extension. The large variations in Si, Al IV , Al VI , Fe, Mg, K and Cl may be related to the combination of different factors, such as Cl-content and related cristal-chemical constraints, whole rock composition, PT conditions of reequilibration, the microdomains where the amphibole grows and the variable a HCl/fluid /a H2O/fluid ratio of the fluid in equilibrium with the amphiboles at various stages of the metamorphic evolution. Amphiboles that locally contain extremely high Cl contents (up to 4% wt) could have been in equilibrium with a locally enriched Cl-fluid. As suggested by the fact that the Cl content of amphibole into the veins is generally lower than in amphibole rims far from the veins, these equilibrium conditions probably were reached at places where the system was locally closed. In addition, hydration reaction consumed the H 2 O component of the fluid, leading to a re-equilibration of the crystallising amphibole with the remaining Cl-enriched fluid. Equilibration temperatures up to 350°C can be attributed to the Apennines amphiboles, and up to 550°C to the ones from the Sesia-Lanzo Zone.

Plasters in the Cellars of the Visconti Castle in Pavia. Physico-chemical characterization

An archaeometric investigation on plaster samples taken from the cellars of the Visconti Castle in Pavia has brought out the existence of several layers and colour films of various periods. The oldest plaster spread over the masonry is formed with three main layers. Above them, one film of bluish-black colour can be found on the arcs and on the bearing walls. On this black layer, a white film of calcitic composition, containing also apatite fragments, was spread. These ancient materials were subsequently covered in more recent times with plasters having different compositions and textures.In the present paper the properties of the three main plaster layers and those of the black film are reported in detail. The thermal behaviour of these materials was studied by means of differential thermal analysis and thermogravimetric analysis. The study was completed with scanning electron microscopy,microprobe analysis and X-ray diffraction on powders.The results obtained provide interesting clues for advancing reasonable hypotheses both on the methods adopted in ancient building yards, and on the techniques for the production of the pigments employed.