Deep-sea benthic foraminiferal recolonisation following a volcaniclastic event in the lower Campanian of the Scaglia Rossa Formation (Umbria-Marche Basin, central Italy)

We studied the distribution of deep water agglutinated foraminiferal (DWAF) assemblages across a 15-cm-thick volcaniclastic layer in the lower Campanian Scaglia Rossa limestones of the Umbria-Marche Basin. Above the volcaniclastic layer, which is devoid of foraminifera, a remarkable pattern of recovery among DWAF has been observed. The complete recovery of DWAF in terms of trophic groups and complexity of assemblages is observed in the first 5 cm above the volcaniclastic layer, representing 4.8 kyr based upon the mean sedimentation rate of the Campanian Scaglia Rossa Formation. In its initial stage, the recovery pattern is remarkably similar to that observed following the 15 June 1991 Mount Pinatubo ashfall in the abyssal South China Sea where various species of Reophax, a small organically cemented species of Textularia, and the calcareous species Quinqueloculina seminula and Bolivina difformis are the earliest recolonisers on top of the tephra layer. Such similarities between modern and fossil analogues strengthens the reliability of environmental reconstructions based on DWAF.