Eocene/Oligocene deep-water agglutinated foraminifera (DWAF) assemblages from the Madonie Mts.

Quantitative and qualitative analysis of deep-water agglutinated foraminifera (DWAF) assemblages from Portella Colla (Madonie Mts.) reveal a variation of the trophic continuum in Late Eocene and Early Oligocene times (Benedetti & Pignatti in press). Twenty-nine samples were processed obtaining 80 agglutinated species, 13 of which in open nomenclature, belonging to 34 genera, which were attributed to the functional morphogroups of Jones and Charnock (1985). Only 7 genera of hyaline benthic foraminifera are recorded. Faunal density increases upsection, whereas specific diversity fluctuates and reaches its minimum near the E/O boundary. In the uppermost Eocene, cyclamminids, Haplophragmoides and Repmanina charoides (Jones & Parker, 1860), epifaunal and lower infaunal forms prefering well-oxigenated bottom water and a normal food supply, prevail. Near the E/O boundary diversity broadly decreases and the assemblages are dominated by opportunistic taxa such as Repmanina charoides. At the beginning of the lower Rupelian, suspension-feeders (group A) and assemblages rich in Paratrochamminoides are present and hyaline taxa disappear. At the end of the lower Rupelian, Nothia, ammodiscids and hyaline foraminifers reappear and deep infaunal morphogroup becomes dominant marking low oxygen bottom water condition. In the upper Rupelian deep infaunal communities (rheophacids and Caudammina) dominate the assemblages and epifaunal surface-dwelling foraminifera decrease. At the sandy input increase (transition from Caltavuturo Fm. to Portella Colla Clays) correspond the LO of Caudammina, suspension feeders and surface-dwellers decrease, oligotypic assemblages are dominated by Reticulophragmium rotundidorsatum. The oxygen bottom water conditions return to tenors similar to those of the upper Eocene, with a medium to high nutrient supply as inferred from the abundance of cyclamminids.