Planktic foraminiferal and partial derivative C-13 isotopic changes acrossthe Paleocene/Eocene boundary at Possagno (Italy)

The interval spanning the Paleocene-Eocene (P/E) transition in the Possagno section consists of 1 m of red marls, including a LC-cm-thick, dark-red '' dissolution" clay, which represents the Paleocene/Eocene boundary event. Th e Possagno section is much more condensed than other Tethyan and North Atla ntic sections previously studied; however, in this section the most signifi cant biotic, isotopic and sedimentological events across the P/E boundary c an be recognized. The Possagno section spans the following planktic foramin iferal subzones: upper part of M. gracilis Subzone, A. berggreni Subzone, A . sibaiyaensis Subzone and probably lowermost part of P. wilcoxensis Subzon e. The quantitative analysis indicates a major increase of low-latitude aca rininids, including compressed tropical acarininids just above the boundary clay. This acarininid incursion begins just below the boundary clay but re aches its maximum just above the clay. The planktic foraminiferal faunal tu rnover is gradual except for the acarininid incursion. The isotopic results show a negative excursion in partial derivative(13)C values at the small b enthic foraminifera mass extinction event. The acarininid maximum diversity coincides with this isotopic excursion, and reflects an increase in surfac e seawater temperature. Despite being very condensed, the Possagno section allows us to further confirm that the different biotic, isotopic and sedime ntological events recognized in the Spanish sections (Alamedilla, Campo, Ca ravaca, Zumaya) are not local in nature and allows the establishment of a d etailed chronostratigraphic framework to define the P/E boundary stratotype .