Marbles from the Campiglia Marittima area (Tuscany, Italy) MARCO FRANZINI 1, * ,MARCO LEZZERINI 1 and FRANCESCA ORIGLIA 2 1 Dipartimento di Scienze della Terra, Universita ` di Pisa, Via S. Maria 53 – 56126 Pisa, Italy *Corresponding author, e-mail: lezzerini@dst.unipi.it 2 Dipartimento di Scienze della Terra, Universita ` di Siena, Via Laterina 8 – 53100 Siena, Italy Abstract: The area surrounding the Tuscan municipality of Campiglia Marittima hosts widespread deposits of thermo-metamorphic marbles that were extensively used as a building and ornamental stones since the time of the Etruscans. The macroscopic characteristics of this class of marble, its chemical, mineralogical, petrographic features as well as the P-T conditions of metamorphic re-crystallisation, C and O stable isotope data and the main physical properties are presented in order to provide a solid basis for possible studies on the provenance and distribution of building stones from this terranes. With the aim to evaluate the effects of thermal stress on these marbles, apparent density and water absorption at atmospheric pressure were measured before and after thermal treatments. Based on a careful survey of the marbles used for building in the area, their uses and state of conservation have also been assessed. Key-words: marble, petrography, XRF, XRPD, SEM/EDS, C-O stable isotopes, physical properties, Campiglia Marittima, Tuscany, Italy. 1. Introduction Various white and coloured marbles outcropping in the Campiglia Marittima area (Tuscany, Central Italy), around the magmatic intrusion of Botro ai Marmi, were formed by contact metamorphism from both the ‘‘stratified black Limestone’’ and ‘‘massive Limestone’’ Formations (Costantini et al., 1993). Some of these marbles such as sta- tuario, bardiglio and flowery bardiglio were widely used as building and ornamental stones since the time of the Etruscans (Merciai, 1936; Casini, 1993; Mannoni et al., 1995), and almost continuously from the Middle Ages until just a few decades ago. A large number of buildings in Campiglia Marittima, as well as street pavements, staircases, border or party walls, and so forth, were made from these rocks. The aim of the present study is to analyse some important properties of these marbles – henceforth referred to as ‘‘Campiglia marble’’ – in order to lay a sound knowledge basis for subsequent archaeometric studies. To this end, we have determined the marble’s main chemical, mineralogi- cal, petrographic, physical characteristics, the peak tem- perature of the metamorphic aureole as well as the carbon and oxygen stable isotope values. The analyses were con- ducted on 25 samples collected near the town of Campiglia Marittima in three old quarries, as shown in Fig. 1, which were extensively exploited until almost recent times (Merciai, 1936; Casini, 1993; Mannoni et al., 1995). The sample collection covers the main varieties of Campiglia marble: coarse-and medium-grained white and white-rose marbles, bardiglio, and flowery bardiglio. Direct observa- tions on the different marbles used in the medieval buildings of the town of Campiglia Marittima enabled assessing their exploitation and state of conservation. Despite centuries- long exposure to weathering process, these materials have proved quite resistant to any alterations in their properties. 2. Geological setting The study area is a tectonic window exhibiting the Tuscan autochthonous series of the Alpine geosyncline (Giannini, 1955; Giannini & Lazzarotto, 1967; Decandia et al., 1981, 1993). Figure 1 shows a simplified geological sketch map of the main units outcropping in the NW Campiglia Marittima area, between Mt. Rombolo and Mt. Spinosa, together with the sampling sites (A, B, C). As proposed by Costantini et al. (1993), the stratigraphic units are: (1) Tuscan Domain formations, including the ‘‘Calcari neri stratificati’’ (‘‘stratified black Limestones’’, Upper Trias) and ‘‘Calcare massiccio’’ (‘‘massive Limestone’’, Lower Lias), formed by carbonate rocks; (2) Liguride Domain formations, including shales, silt- stone and calcarenites (Upper Cretaceous); (3) Neoautochthonous sediments, made of a sequence depos- ited in tectonically subsiding basins originated during the Neogene and Quaternary post-collisional extension; (4) Neogene Magmatic Complex, which is represented by the Botro ai marmi granodiorite, cordierite-bearing *Passed away on 15/05/2010 0935-1221/10/0022-2056 $ 5.85 DOI: 10.1127/0935-1221/2010/0022-2056 # 2010 E. Schweizerbart’sche Verlagsbuchhandlung, D-70176 Stuttgart Eur. J. Mineral. 2010, 22, 881–893 Published online November 2010