Trace Element Classification Diagrams of Pyroclastic Rocks from the V olcanic Districts of Central I taly: the Case Study of the Ancient R oman Ships of P isa

Identification of the volcanic material (pozzolan) stored in a R oman ship of the fourth to third century bce , wrecked in the ancient harbour of Pisa (central I taly), was based on ratios of selected trace elements. The compositions of the major volcanic products erupted by the volcanoes of the R oman province, including the volcanic districts of Latium ( V ulsini, V ico, M onti S abatini and the A lban H ills) and C ampania ( R occamonfina, the P hlegraean F ields, I schia, P rocida and V esuvius) are compared with the pozzolan from the Pisa ship. Superposition of the Z r/ Y , N b/ Y and N b/ Z r ratios of the pyroclastic material from the wrecked ship (computed from the published literature) allows correlation with the products of the O nano eruption from the V ulsini V olcanic D istrict. The V ulsini rocks outcrop extensively in a sector drained by the hydrographic network of the F iora R iver, which has been a well‐developed commercial water trade route since E truscan times, with a river port and a sea port connected to the important town of V ulci, and, since 273 bce , part of the larger R oman harbour system of C osa.