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Dipartimento di Scienze della Terra, Università degli Studi di Camerino, Italy
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- PublicationOpen AccessGrowth and subsidence of carbonate platforms: numerical modelling and application to the Dolomites, Italy(2004)
; ; ; ;Marella, C.; Dipartimento di Scienze della Terra, Università degli Studi di Camerino, Italy ;Caputo, R.; DiSGG, Università degli Studi della Basilicata, Potenza, Italy ;Bosellini, A.; Dipartimento di Scienze della Terra, Università degli Studi Ferrara, Italy; ; The phenomenon of subsidence induced by the growth of carbonate platforms has been investigated with the aid of numerical modelling. The research aimed to quantify the relative contribution of this process in the creation of the accommodation space required to pile up thick neritic bodies. We analysed two end-member deformation styles, namely the elastic behaviour of the lithosphere when locally loaded and the plastic-like reaction of a sedimentary succession underlying a growing carbonate buildup. The former process, analysed using a modified flexural model, generates a regional subsidence. In contrast, the latter process, simulated by considering the compaction occurring in soft sediments, generates a local subsidence. We attempted to quantify the amount and distribution of subsidence occurring below and surrounding an isolated platform and in the adjacent basin. The major parameters playing a role in the process are discussed in detail. The model is then applied to the Late Anisian-Early Ladinian generation of carbonate platforms of the Dolomites, Northern Italy, where they are spectacularly exposed. Taking also into account the Tertiary shortening that occurred in the area, both local and regional subsidence contributions of major platform bodies have been calculated aimed at a reconstruction of the map of the induced subsidence. A major outcome of this study is that the accommodation space, that allowed the accumulation of very thick shallow-water carbonate successions in the Dolomites, was only partially due to lithospheric stretching while the contribution given by the 'local' overload is as high as 20-40% of the total subsidence. Our results also shed some light on the water-depth problem of the Triassic basins as well as on the basin-depth to platform-thickness relationships.137 222 - PublicationOpen AccessThe Palermo (Sicily) seismic cluster of September 2002, in the seismotectonic framework of the Tyrrhenian Sea-Sicily border area(2004)
; ; ; ; ; ; ; ; ; ; ;Giunta, G.; Dipartimento di Geologia e Geodesia, Università degli Studi di Palermo, Italy ;Luzio, D.; Dipartimento di Chimica e Fisica della Terra (CFTA), Università degli Studi di Palermo, Italy ;Tondi, E.; Dipartimento di Scienze della Terra, Università degli Studi di Camerino, Italy ;De Luca, L.; Dipartimento di Chimica e Fisica della Terra (CFTA), Università degli Studi di Palermo, Italy ;Giorgianni, A.; Dipartimento di Geologia e Geodesia, Università degli Studi di Palermo, Italy ;D'Anna, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Renda, P.; Dipartimento di Geologia e Geodesia, Università degli Studi di Palermo, Italy ;Cello, G.; Dipartimento di Scienze della Terra, Università degli Studi di Camerino, Italy ;Nigro, F.; Dipartimento di Geologia e Geodesia, Università degli Studi di Palermo, Italy ;Vitale, M.; Dipartimento di Chimica e Fisica della Terra (CFTA), Università degli Studi di Palermo, Italy; ; ; ; ; ; ; ; ; The northern coast of Sicily and its offshore area represent a hinge zone between a sector of the Tyrrhenian Basin, characterized by the strongest crustal thinning, and the sector of the Sicilian belt which has emerged. This hinge zone is part of a wider W-E trending right-lateral shear zone, which has been affecting the Maghrebian Chain units since the Pliocene. Seismological and structural data have been used to evaluate the seismotectonic behavior of the area investigated here. Seismological analysis was performed on a data set of about 2100 seismic events which occurred between January 1988 and October 2002 in the Southern Tyrrhenian Sea. This paper focuses in particular on a set of data relating to the period from 6th September 2002, including both the main shock and about 540 aftershocks of the Palermo seismic sequence. The distribution of the hypocenters revealed the presence of two main seismogenic zones. The events of the easternmost zone may be related to the Ionian lithospheric slab diving beneath the Calabrian Arc. The seismicity associated with the westernmost zone is closely clustered around a sub-horizontal regression plane contained within the thinned Southern Tyrrhenian crust, hence suggesting that this seismogenic zone is strictly connected to the deformation field active within the hinge zone. On the basis of both structural and seismological data, the brittle deformation pattern is characterized by high-angle faults, mainly represented by transcurrent synthetic right-lateral and antithetic left-lateral systems, producing both restraining/uplifting and releasing/subsiding zones which accommodate strains developing in response to the current stress field (characterized by a maximum axis trending NW-SE) which has been active in the area since the Pliocene. The cluster of the seismic sequence which started with the 6th September 2002's main shock is located within the hinge zone. The distribution of the hypocenters relative to this sequence emphasizes the presence of a high-angle NE-SW-oriented deformation belt within which several shear surfaces are considered to be found sub-parallel to that established for the main shock. The kinematics of all these structures is consistent with a compressive right-lateral focal mechanism.310 2003