Archaeological Stratification in the St. Leucio Basilica (2nd Century BCE–6th Century CE, Canosa di Puglia, Southern Italy): Archaeometric Analysis of Pebble Pavements

This paper presents the results of an archaeometric investigation of the preparatory mortars of the pebble pavements of the Basilica of St. Leucio in Canosa di Puglia (Bari, Southern Italy). The main aim of the presented study is to contribute to the dating of some portions of the pebble pavements by analyzing the preparatory layers and determining whether they pertain to the basilica (6th century CE) or to the pre-existing temple (2nd century BCE–4th century CE). Further purposes are to provide information about the production technologies of the mortars and to identify the nature of the pigments found on some pebbles. In order to contribute to the dating studies of the floors, complicated by previous reuse and restoration, 12 samples of mortars, sometimes including pebbles, were collected in different areas of the site. They were analyzed by polarized light microscopy (PLM), X-ray diffractometry (XRPD), X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy coupled with an energy-dispersive spectrometer (SEM-EDS). The results allowed us to advance chronological data on different pavement areas, to deepen our knowledge on mortar production, in terms of both raw materials and technology, and to identify red ochre as the pigment with which the pavement surface was painted.