Conodont biostratigraphy of uppermost Triassic deep-water calcilutites from Pizzo Mondello (Sicani Mountains): Evidence for Rhaetian pelagites in Sicily

Abstract

Rhaetian pelagites are described for the first time from Western Sicily in the Pizzo Mondello area (Sosio Valley, Sicani Mountains) where a thick pile of Upper Triassic cherty calcilutites outcrops. The Upper Triassic pelagic calcilutites of Pizzo Mondello are divided into three lithostratigraphic units. The lower unit consists of a few meters of dark gray marls and clay marlstones (equivalent to the Mufara Fm.) of Carnian age followed by Halobia-bearing cherty limestones (about 300 m thick) of Late Carnian—Late Norian age. The upper unit consists of white calcilutites and grey-greenish marls containing the conodonts Misikella posthernsteini and Zieglericonus rhaeticus of Rhaetian age. These Rhaetian deposits are here informally named as Portella Gebbia Limestone. In the Pizzo Mondello succession the Norian/Rhaetian boundary, sensu Kozur and Mock (1991), can be approximated along the lowermost calcilutite bed of Portella Gebbia Limestone containing the first occurrence of M. posthernsteini.