The marble Portasanta from Caldana (Grosseto-Italy) takes the name for its strict resemblance with the ancient Marble Chium (called also Portasanta) coming from Chios island (Greece). The italian lithotype is a fine pale pink and red limestone from massive to brecciated. In Florence this litotype is present in the floor of the Florence Cathedral, as covering of the walls of “Tribuna di Galileo” in the Specola Museum, in four columns of monumental chapels in the the SS. Annunziata Church, in some lateral icons of the Carmine and Orsanmichele Churchs, and in the jambs of some doors of the Palatina Gallery in the Pitti Palace. In this work mineralogical (XRD analyses on the bulk sample and on insoluble residue after acid attack), physical (porosity accessible to water), chemical (XRF and isotopic analyses), petrographycal (OM) and mechanical (compressive text) characterisations have been carried out in order to realize a comparison between the Italian marble and the ancient Greek marble. This characterisation can help making a better distinction between these two litotypes sometime mistaken. The samples were taken in the quarry located along the road leading from Ravi to Caldana. The macroscopic aspect varies from massive to brecciated. The stone belongs to the Calcare Massiccio Formation dating back to Hettangiano-Sinemuriano Petrographically the massive variety can be classified as a wackestone while the brecciated varieties are characterized by micritic centimetric clasts in a partially recrystallized carbonatic matrix. The porosity accessible to water varies from a value < 1% for the massive variety, to values > 4% for the breccias. The mineralogical composition of the bulk samples is constituted by calcite in prevalence and quartz. Sometimes clay minerals are present in trace. Dolomite is absent. In the chemical analysis of the bulk sample, CaO ranges from 50.46 to 57.39 % and MgO from 0.37 to 1.11%. The variation of the C and O isotopic values is from –1.79 to + 2.90 for the 13C PDB, and from –17.30 to –8.11 for the 18OPDB. The analyses of insoluble residue after acid attack and the compressive texts are in progress. The preliminary results allow to compare the data of the Italian and Greek Portasanta marbles; it is possible confirm considerable chemical and petrographical differences between the two litotypes.

Caratterizzazione minero- petrografica e fisico-meccanica del “marmo” Portasanta della Toscana meridionale: utilizzo ed impiego storico (extended abstract) / E. Cantisani; E. Pecchioni; C. Garzonio; F. Fratini; R. Sartori. - STAMPA. - (2006), pp. 155-161. ((Intervento presentato al convegno Atti del Convegno: Risorse lapidee dall'antichità ad oggi in area mediterranea tenutosi a Canosa di Puglia (Bari nel 25 - 27 Settembre 2006.

Caratterizzazione minero- petrografica e fisico-meccanica del “marmo” Portasanta della Toscana meridionale: utilizzo ed impiego storico (extended abstract)

PECCHIONI, ELENA;GARZONIO, CARLO ALBERTO;
2006

Abstract

The marble Portasanta from Caldana (Grosseto-Italy) takes the name for its strict resemblance with the ancient Marble Chium (called also Portasanta) coming from Chios island (Greece). The italian lithotype is a fine pale pink and red limestone from massive to brecciated. In Florence this litotype is present in the floor of the Florence Cathedral, as covering of the walls of “Tribuna di Galileo” in the Specola Museum, in four columns of monumental chapels in the the SS. Annunziata Church, in some lateral icons of the Carmine and Orsanmichele Churchs, and in the jambs of some doors of the Palatina Gallery in the Pitti Palace. In this work mineralogical (XRD analyses on the bulk sample and on insoluble residue after acid attack), physical (porosity accessible to water), chemical (XRF and isotopic analyses), petrographycal (OM) and mechanical (compressive text) characterisations have been carried out in order to realize a comparison between the Italian marble and the ancient Greek marble. This characterisation can help making a better distinction between these two litotypes sometime mistaken. The samples were taken in the quarry located along the road leading from Ravi to Caldana. The macroscopic aspect varies from massive to brecciated. The stone belongs to the Calcare Massiccio Formation dating back to Hettangiano-Sinemuriano Petrographically the massive variety can be classified as a wackestone while the brecciated varieties are characterized by micritic centimetric clasts in a partially recrystallized carbonatic matrix. The porosity accessible to water varies from a value < 1% for the massive variety, to values > 4% for the breccias. The mineralogical composition of the bulk samples is constituted by calcite in prevalence and quartz. Sometimes clay minerals are present in trace. Dolomite is absent. In the chemical analysis of the bulk sample, CaO ranges from 50.46 to 57.39 % and MgO from 0.37 to 1.11%. The variation of the C and O isotopic values is from –1.79 to + 2.90 for the 13C PDB, and from –17.30 to –8.11 for the 18OPDB. The analyses of insoluble residue after acid attack and the compressive texts are in progress. The preliminary results allow to compare the data of the Italian and Greek Portasanta marbles; it is possible confirm considerable chemical and petrographical differences between the two litotypes.
Le risorse lapidee dall'Antichità ad oggi in area mediterranea
Atti del Convegno: Risorse lapidee dall'antichità ad oggi in area mediterranea
Canosa di Puglia (Bari
25 - 27 Settembre 2006
E. Cantisani; E. Pecchioni; C. Garzonio; F. Fratini; R. Sartori
File in questo prodotto:
File Dimensione Formato  
Cantisani et al_Portasanta.pdf

Accesso chiuso

Descrizione: pdf articolo
Tipologia: Pdf editoriale (Version of record)
Licenza: DRM non definito
Dimensione 1.19 MB
Formato Adobe PDF
1.19 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2158/351334
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact