A Geological Itinerary Through the Southern Apennine Thrust-Belt (Basilicata—Southern Italy)

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Contrasting styles of (U)HP rock exhumation along the Cenozoic Adria-Europe plate boundary (Western Alps, Calabria, Corsica)

Since the first discovery of ultrahigh pressure (UHP) rocks 30 years ago in the Western Alps, the mechanisms for exhumation of (U)HP terranes worldwide are still debated. In the western Mediterranean, the presently accepted model of synconvergent exhumation (e.g., the channel-flow model) is in conflict with parts of the geologic record. We synthesize regional geologic data and present alternative exhumation mechanisms that consider the role of divergence within subduction zones. These mechanisms, i.e., (i) the motion of the upper plate away from the trench and (ii) the rollback of the lower plate, are discussed in detail with particular reference to the Cenozoic Adria-Europe plate boundary, and along three different transects (Western Alps, Calabria-Sardinia, and Corsica-Northern Apennines). In the Western Alps, (U)HP rocks were exhumed from the greatest depth at the rear of the accretionary wedge during motion of the upper plate away from the trench. Exhumation was extremely fast, and associated with very low geothermal gradients. In Calabria, HP rocks were exhumed from shallower depths and at lower rates during rollback of the Adriatic plate, with repeated exhumation pulses progressively younging toward the foreland. Both mechanisms were active to create boundary divergence along the Corsica-Northern Apennines transect, where European southeastward subduction was progressively replaced along strike by Adriatic northwestward subduction. The tectonic scenario depicted for the Western Alps trench during Eocene exhumation of (U)HP rocks correlates well with present-day eastern Papua New Guinea, which is presented as a modern analog of the Paleogene Adria-Europe plate boundary

Can we assess earthquake size by measuring the fractal dimension of active faults?

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Cinematica del settore centrale del Mediterraneo ed implicazioni sulla strutturazione dell’Arco Calabro.

In questo lavoro viene proposto un approccio metodologico di tettonica globale per 1'analisi del sistema di catene e bacini dell'area mediterranea (SIME). Vengono discussi: un possibile modello evolutivo del settore centrale dell'area e la sua storia deformativa. Quest'ultima e stata schematicamente rappresentata in tre momenti (stadi) nell'ambito dei quali possono riconoscersi diverse fasi tettoniche comprensive di eventi di ordine inferiore. Dalla nostra ricostruzione emerge chiaramente l'importanza dell'arco calabro nell'evoluzione complessiva del sistema. Dalle fast di individuazione dei margini continentali europeo ed africano l'area dalla quale l'arco deriva ha, infatti, sempre occupato una posizione centrale rispetto ai blocchi iberico, sardocorso ed afro-apulo. In conclusione a questa premessa riteniamo tuttavia doveroso precisare che, data la natura del lavoro e la necessita di essere sintetici, per molti degli argomenti a sostegno delle nostre tesi il lettore dovrà fondare il suo giudizio più sui riferimenti bibliografici che non sulla completezza delle informazioni fornite. Cio premesso, per gli aspetti specialistici e/o per i dati di carattere regionale sulla struttura dell'arco calabro, si rimanda alia bibliografia più recente e/o significativa. Per un inquadramento geologico dell'area rimandiamo invece ai lavori pubblicati negli atti del convegno della SGI "L'arco calabro-peloritano nell'orogene appenninico-maghrebide", fortemente voluto dal Prof. Ippolito, al quale dedichiamo questo lavoro poichè lo riteniamo "responsabile" della nostra passione per la geologia della Calabria e per la curiosita che ha saputo insegnarci per gli argomenti "di frontiera" nelle Scienze della Terra

Strutture sismogenetiche in Appennino Centrale: potenziale sismico, analisi frattale e processi di crescita

The seismogenic structures of the axial zones of the Central Apennines Fault System have been recognized by means of detailed analyses of the capable faults exposed along a main deformation zone extending from Camerino to L'Aquila. The fault system also includes lower-rank faults, trending roughly NW-SE and N-S, showing normal and strike-slip components, respectively. Expected maximum magnitudes associated with normal and/or transtensional fault segments are lower than 6.0, whereas those expected from the activation of strike-slip faults may be high as 7.0. The results obtained from our study suggest that seismic activity in the area in mainly due to the development and evolution of a N-S trending strike-slip system composed of 3 main structures, each of which characterized by a surface fault pattern with specific fractal properties. The central structure of the system was interpreted to be the major seismogenic structure in the area and is thought to be responsible for the 1703 seismic sequence in Central Italy

Evidenze di processi deformativi continui e tettonica trascorrente nel Cnale di Sicilia: le Isole Maltesi.

In this paper we report the results of a study concerning the macro and meso-structures affecting the oligo-miocene succession and a few quaternary deposits outcropping in the maltese islands. Data analysis allowed us to define in detail the geo-structural setting of the study area and to put in evidence the mode of deformation responsible for its generation. The main conclusions that can be drawn indicate that the area in question has been affected by a progressive deformative process during which it is possible to isolate a series of tectonic events that are characterized by different geometries of the stress field. The above information together with available data relative to the surrounding regions (Tunisia, Pelagian block and Pantelleria) also made it possible to discuss in detail the temporal relations among the deformative events with the aim of obtaining a better understanding of the neotectonic evolution of the whole sector located between the undeformed african continental margin and the Sicilian maghrebide chain