BENTHIC FORAMINIFERA RECOVERY AFTER CENOMANIAN-TURONIAN BOUNDARY MASS EXTINCTION IN CARBONATE PLATFORM FROM SOUTHERN APENNINES (ITALY)

The shallow‐water carbonates of Apennine platform registered complete Cenomanian-Turonian, in which occurs one of the major episode of carbon rich sediment deposition wide known as Oceanic Anoxic Event 2 (OAE2), in which larger foraminifera disappeared in two successive steps separated by150 k. y.; in the first step, mainly the extreme k‐strategist foraminifera like alveolinids such as Cisalveolina fraasi, together with other morphosturctural very genera as Broekina¸ and Coxites; while during the second step all the remainder less complex foraminifera as Chrysalidina sp. and Pseudorhapydioninids were eliminated. Here we give the first detailed characterization of the most typical shallow benthic foraminiferal assemblages for the Turonian from the Apennine carbonate platform of southern Italy, and its chronostratigraphic range firmly constrained by integrating carbon and strontium isotope stratigraphy (SIS).

Three sections were studied: Monte Coccovello, Raia del Pedale and Varchera, located at the Campania Region, Southern Italy (near from Napols), by thin sections and the chronostratigraphic calibration of the studied sections is based on the integration of carbon and strontium-isotope stratigraphy.

The recovering phase after the Cenomanian-Turonian extinction started during the Lower Turonian and continues during Middle - Upper Turonian. The first foraminifera appearing in the fossil record are very small and have simple structures as Nezzazatinella sp. and Pseudocyclammina spharoidea Gendrot, 1968, the last is widely known for Coniacian age, appears here from the lower Turonian. Is also very common the presence of Montcharmontia apenninica (De Castro 1966), which characterizes the upper Cretaceous for the Tethysian Realm, appearing here in the Lower Turonian, just after the CTB.

The complex structures arose in the Apennine platform about 2.5 m.y after the Cenomanian –Turonian boundary, during Middle-Upper Turonian with Reticulinella kaeveri Cherchi, Radoičić and Schroeder, 1989, Scandonea sammítica De Castro, 1971. Also the Cuneolina sp., Dicyclina sp. and Vercosellasp. are present through all interval as common genera for the Upper Creteaceous in the Southern Appenines platform.