Protopeneroplis trochangulata SEPTFONTAINE, 1974 (Foraminiferida) NEL CRETACEO INFERIORE DELL'AREA DEL GRAN SASSO D'ITALIA (ABRUZZO)

Abstract

The paleoecologic significance and the stratigraphìc position of Protopeneroplìs trochangulata SEPTFONTAL'<E, 1974, in the Gran Sasso d'Italia area (Abruzzo), are discussed. P. trochangulata has been recognized in severa! carbonatic se­quence in which three/acies are represented: carbonatic paltform­edge facies, pelagic-detritìc facies and internal carbonate platform facies. In the first facies the caraceteristic species P. trochangulata lived ìn association with incrusting calcareous Algae (Lithocodìum­Bacinella ), great Dasycladales, Codiaceae and other typical bentho­nic Foraminifera. P. trochangulata and other fossils from the first facìes appear to have been reworked and re-deposited in the envi­ronments which characterize the other two facies. This fossils man­tain their stratìgraphic signifìcance, since the time interval between the origina! depositìon and the subsequent re-deposition is very short. The autochtonous microfaunas accompanying P. trochangu­lata in the pelagic-detritic sequences, indicate precisely that this spe­cies appeared the Berriasian and totally disappeared around the end of the Valanginian.