Geochemical characterisation of pozzolanic obsidian glasses used in the ancient mortars of Nora Roman theatre (Sardinia, Italy): provenance of raw materials and historical–archaeological implications
Columbu, Stefano
First
Writing - Review & Editing
;Garau, Anna MariaSecond
Formal Analysis
;Lugliè, CarloLast
Writing - Original Draft Preparation
2019-01-01
Abstract
The study focused on the volcanic glass used in the production of bedding mortars and concrete of the Roman theatre (I cent. AD) of the Nora site. The volcanic glasses were frequently used as aggregate and with pozzolanic function in all hydraulic mortars of the different sectors of the building (e.g., concretes of tribunalia vaults and external niches, jointing and foundation mortars of cavea tier ashlars, brick bedding), together with mainly quartz-feldspar sands, local Oligo-Miocenic andesitic-dacitic volcanics and Palaeozoic and Tyrrhenian sedimentary rocks. These volcanic glasses show characteristics closer to obsidian than to natural pozzolan normally used in the Roman period. They have definitely not sourced locally, unlike the other components that make up the aggregate. To identify their provenance, a petrochemical comparison between several samples taken from the theatre mortars and the volcanic outcrops of some probable Sardinian source areas is made. The use of the not local pozzolanic glass is a technical innovation in the mortars of the Nora archaeological site, and considering the wide use of obsidians in the prehistoric periods for the production of tools, significant considerations about its origin, procurement and use are made.File | Size | Format | |
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Columbu_Garau_Lugliè 2018.pdf Solo gestori archivio
Description: Articolo principale
Type: versione editoriale
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10.23 MB | Adobe PDF | & nbsp; View / Open Request a copy |
Columbu et al 2019 version Post print.pdf open access
Description: Articolo completo di testo, figure e tabelle
Type: versione post-print
Size 5.95 MB
Format Adobe PDF
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5.95 MB | Adobe PDF | View/Open |
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