The provenance of the white marble from the Torre Civica excavations (Pavia-Italy)

We sampled 51 white marble fragments from the Pavia Torre Civica (excavations 1972-73: 49 samples; debris from its collapse in 1989: 2 samples) and 1 fragment (2 samples) from a Roman column reused in the 19th century Milan gate of the city, together with 75 samples from white marble quarries in the central and eastern Mediterranean basin; the aim of our study was to examine the circulation of marble in Roman Pavia and to verify the results of previous petrographic research. The Torre Civica samples, stratigraphically datable to the later Middle Ages, document the reuse of the precious building materials of Roman Pavia, and can thus be considered a representative sample of the marble circulating in the city in the Roman period. The samples underwent instrumental neutron activation analysis (INAA) at the Triga Mark II reactor facility at the University of Pavia; we determined 12 rare earth elements (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) and 10 trace lements (Ba, Co, Cr, Cs, Hf Rb, Sb, Sc, Th, U). Stepwise discriminant analysis, a technique for the description and testing of inter-group differences, was applied to identify those variables with the greatest discriminant power. The most significant variables were: Ce, Yb, Th, Sc and Cs. Using these variables, cluster analysis separated the samples into 5 provenance groups (the Massa Carrara area, Hymettus, Pentelikon, Marmara, Paros) Our results show that although 32 (62.7%) samples were provenanced as from the quarries near Massa Carrara, 19 (37.3%) were assigned to east Mediterranean quarries (Hymettus - 2; Pentelikon - 7; Marmara - 6; Paros -4), thus confirming the close commercial links between the Adriatic and Aegean basins in antiquity.