Geology and paleontology of the South-western carbonate edge of Fucino Plain (Abruzzi, central Apennines)

This paper describes the carbonate succession of Lower Cretaceous to Middle Miocene sediments cropping out along the south-western edge of Fucino Plain. Particular attention was given to the paleontological analysis of these limestones, aimed at defining the stratigraphy, paleoecological and paleoenvironmental conditions of the area under investigation. The mountain relief is divided into two sections by the confluence of the Vallelonga depression and Fucino Plain. The section to the E of the Vallelonga depression (Trasacco mountains) is limited along the valley by a normal fault with NW-SE strike and it consists of Hauterivian-Albian limestones overlaid by limited transgressive Middle Miocene limestones. These ones have never been reported before in the literature; they are the document of the extended stratigraphic gap which characterized this area in the Late Cretaceous and Paleogene times. The analysis of textural, sedimentological and paleontological data has led to the discovery of a stretch of the carbonate platform edge on the relief northern slope: on the contrary the remaining part of the mountain structure presents inner platform-lagoon environmental conditions. In the section to the W of the Vallelonga depression (Luco dei Marsi-Madonna Candelecchia area), Upper Aptian to Campanian limestones crop out; depositional environment changed from restricted conditions in the Aptian-Albian time to open platform environment in the Senonian one. This general outline allow us to conclude that, during the Cretaceous time, the Vallelonga fault has probably downthrown the western section of the area where the sedimentation continued until the Campanian time.