Platform-to-basin facies transition and tectono-sedimentary processes in the Jurassic deposits of the Furlo area (Umbria-Marche Apennines, Italy)

The Jurassic successions of the Furlo area (Northern Marche, Italy) are characterized by complex tectono-stratigraphic relationships related to the extreme differentiation of depositional environments occurring from the early Jurassic. In the area of the future Umbria-Marche Apennines, including the Furlo sector, the Sinemurian tectonic event dismembered the wide peritidal carbonate platform of the Calcare Massiccio Fm. into a series of uplifted and downthrown platform blocks bounded by extensional faults. The subsequent drowning of these blocks led to the development of two main environments: pelagic carbonate platforms and basins. The present paper focuses on an analysis of facies that characterize some paleogeographic sectors connecting these two different environments in order to understand the role of tectonics as a control on sedimentary processes. In these sectors, different types of facies have been identified and interpreted. Relationships between facies types, their stacking pattern, and sedimentary structures enabled the identification of different depositional processes directly or indirectly controlled by the tectonic evolution of the study area. The data compiled, compared with those from the literature, were used to relate the Furlo area to a general pelagic carbonate ramp environment constituted by two tilted and drowned carbonate platform blocks; these originated as a result of early Jurassic tectonic activity characterized by some approximately perpendicular faults showing a prevailing rotational character

Jurassic carbonate depositional systems of the Mt. Catria-Mt. Acuto area (Umbria-Marche Apennines, Italy)

A geologic survey, integrated with sedimentalogic observations nd macrofacies analysis, has been carried out for the Jurassic eposits outcropping in the Mt. Catria-Mt. Acuto area. he study area is located within the northern Umbria-Marche pennines and is characterized by the presence of Jurassic different type sucessions that reflect depositional environment variability. te aim of this paper is to reconstruct the Jurassic paleographic structural etting and the paleotectonic evolution of the area. Parti - cular attention was given to the characterization of the relationships between deposits formed during and after the drowning of the Calcare Massiccio peritidal carbonate platform. In addition, the depo - sitional trend of this carbonate platform was determined by the charac terization of tidal environment sedimentary structures and facies associations. The data obtained allowed for the identification of two isolated, uplifted blocks of the carbonate platform (Corno di Catria and Mt. Acuto), reduced in size, bounded by escarpments of tectonic origin and separated by a narrow Jurassic basinal area (Mt. Catria). Along paleoslopes of structural highs, drowning Calcare Massiccio “B”-type deposits have been identified that differ from Calcare Massiccio “B” deposited on the tops of paleohighs in their mainly lithoclastic facies. The drowning phase, at the tops as well as along the flanks of the blocks, is also marked by unconformity surfaces (drowning unconformities). The different paleostructural sectors have been differentiated during the Lias by a phase of strong extensional tectonics that was responsible for the formation of the tectonic escarpments, subsequently affected by submarine erosion. In the early stages of the Middle Jurassic, tectonic reactivation resulted in formation of some marginal, down-dropped portions of the structural highs, which were subsequently filled by the same cherty sediments that deposited in the Mt. Catria basinal area. In the study area, the depositional environment has remained differentiated throughout the Jurassic as evidenced by the presence of conformable and unconformable boundaries between the Tithonian calpionellid pelagites of the Maiolica Formation and underlying deposit

First record of ammonites in the Bonarelli Level (uppermost Cenomanian) of the Umbria-Marche Succession

The presence of ammonites in the Bonarelli Level (uppermost Cenomanian) of the Umbria-Marche Succession is reported here for the first time. The horizon studied has been recognised near Serra S. Abbondio, on the external limb of the Mt. Catria anticline, where the upper part of the Scaglia Bianca Formation and the interbedded Bonarelli Level crop out. An ammonite, preserved as a bidimensional trace, has been found within one black shale bed which characterizes the level. The lack of diagnostic elements does not allow a precise taxonomic identification. However, based on the morphologic features, this form can be tentatively ascribed to the suborder Lytoceratin

Space/time tectono-sedimentary evolution of the Umbria-Romagna-Marche Miocene Basin (Northern Apennines, Italy): a foredeep model.

The space/time evolution of the Umbria-Romagna-Marche domains of the northern Apennine Miocene foredeep is proposed. In this period, the turbidite siliciclastic sedimentation is represented mainly by the Miocene Marnoso-Arenacea Formation, which generally ends with mainly marly deposits. From the internal Apennine sectors (Umbria-Romagna domain) to the external Adriatic Margin (Marche domain) the siliciclastic succession overlies hemipelagic marly deposits (Schlier Formation). The whole depositional area can be considered as a single wide basin with depocenter or main sedimentation areas progressively migrating eastwards. This basin is characterized by some morphological highs which did not constitute real dams for the sedimentary flow(turbidity currents). Multiple feeding (arkose, litharenites, calcarenites) from different sources is related to palaeogeographical and palaeotectonic reorganization of the most internal, previously deformed, Apennine areas. The activation of the foredeep stage is marked by the beginning of the siliciclastic sedimentation (Late Burdigalian in the most internal sector). This sedimentation ends in the most external sector in the Early Messinian, pointing to a depositional cycle of about 9–10 Ma. The diachronism of the base of the siliciclastic deposition proves to be almost 5 Ma. The syn-depositional compressional deformation, which shows a marked diachronism, affected the internal area of the foredeep in the Early-Middle Serravallian, and progressively migrated up to Late Miocene, involving more and more external sectors. The deformed siliciclastic sedimentary wedge constitutes an orogenic pile incorporated in the Apennine Chain, represented by different tectonic elements superimposed by means of NE-vergent thrusts. The main stratigraphic and tectonic events of the Toscana-Romagna-Marche Apennines are presented in a general framework,resulting also in a terminological revision