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Welcome to the crossreads-petrography wiki!

Petrographic studies of archaeological materials is a common topic in interdisciplinary projects. However, the supports of epigraphic documents seem to have escaped this analytical approach, leaving the material aspects of inscriptions widely understudied.
Crossreads provides the first systematic study of the materials of stone epigraphy in Sicily, by applying a multi-analytical approach that considers at the same time the analytical questions (what rock is it? what is its composition? where does it come from?) and the conservation of cultural heritage objects by minimizing sampling. Typically, minero-petrographic studies in geological projects require a sample for laboratory analyses. The sample is typically weighing from a few grams to kilograms, and it allows the preparation of multiple specimens for (geo)chemical, mineralogical, petrographic analyses. On the other hand, sampling of cultural heritage is limited to much smaller fragments, typically as small as an almond or smaller. Thanks to the development of portable analytical instruments, it is nowadays possible to perform fully non-invasive analyses directly on the objects, in the museum or at the archaeological site. This latter approach was used extensively during Crossreads.

A total of ca. 5000 individual pXRF spectra were acquired in situ, with ca. 2600 analysed spots on more than 600 inscriptions. Almost 850 inscriptions were subjected to microscopy (digital microscopy in situ). Ca. 250 samples were collected and characterized in the laboratory with optical microscopy on thin sections and XRD on the powder. Of these, ca. 100 marble samples were subjected to stable isotope analyses and a subset of 50 to LA-ICP-MS and EPR.

The analytical work, whose details are in this wiki, allowed to propose an identification and hence a provenance of the rocks used as epigraphic supports in Sicily. A careful review of geological maps and literature on Sicily, as well as on archaeological marbles, allowed to devise a hierarchical vocabulary for describing rocks within an interdisciplinary project. Each identified lithotype is defined by a subtype, type and ana value, as well as a text description in the EpiDoc file. Additionally, locations are provided for visualisation on a map. A Lithotype filter has been added to the I.Sicily website to explore materials in conjunction with the epigraphic data.