“…Clear provenance signals are carried by trace metals, such as Cr, hosted preferentially in mafic and ultramafic rocks, even in distal segments of the routing system (von Eynatten et al ., ; Amorosi, ; Garzanti, ). The original provenance signal can be confounded by changes in grain size, but alumina is effective as a normalization factor (Covelli & Fontolan, ; Menon et al ., ; Liaghati et al ., ): Cr/Al 2 O 3 , in particular, has been tested successfully in Po Plain sediments for discriminating mafic/ultramafic from non‐mafic/ultramafic provenances (Amorosi et al ., , 2014b; Curzi et al ., ; Amorosi, ; Di Giuseppe et al ., ). The best proxy for carbonate (dolostone) versus siliciclastic contribution based on single ratios was MgO/Al 2 O 3 (Amorosi et al ., , ; Curzi et al ., ; Greggio et al ., ), which in this area closely reflects the abundance of dolomite in the sediment (Marchesini et al ., ).…”