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Mantovani, E.
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Mantovani, E.
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- PublicationOpen AccessPlate convergence, crustal delamination, extrusion tectonics and minimization of shortening work as main controlling factors of the recent Mediterranean deformation pattern(1997-06)
; ; ; ; ; ;Mantovani, E.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Tamburelli, C.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Babbucci, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Viti, M.; Dipartimento di Scienze della Terra, Università di Siena, Italy; ; ; ; It is argued that the time-space distribution of major post middle Miocene deformation events in the Central-Eastern Mediterranean region, deduced from the relevant literature, can be coherently explained as a consequence of the convergence between the Africa/Arabia and Eurasia blocks. This plate convergence has mainly been accommodated by the consumption of the thinnest parts of the Northern African (Ionian and Levantine basins) and peri-Adriatic margins. During each evolutionary phase the space distribution of trench zones is controlled by the basic physical requirement of minimizing the work of horizontal forces, induced by plate convergence, against the resisting forces, i.e., the cohesion of the upper brittle crustal layer and the buoyancy forces at the consuming boundaries. The significant changes of tectonic styles which determined the transition from one phase to the next, like those which occurred around the Messinian and the late Pliocene-early Pleistocene, were determined by the suture of consuming boundaries. When such an event occurs, the system must activate alternative consuming processes to accommodate the convergence of the major confining blocks. The observed deformations in the study area suggest that this tectonic reorganization mostly developed by the lateral extrusion of crustal wedges away from the sutured borders. This mechanism allowed the translation of maximum horizontal stresses from the locked collisional fronts to the zones where consumable lithosphere was still present, in order to activate the next consuming processes. The extensional episodes which led to the formation of basins and troughs in the Tyrrhenian and Aegean zones are interpreted as secondary effects of the outward escape of crustal wedges, like those which occurred in response to longitudinal compressional regimes in the Apennines and Aegean regions.324 1047 - PublicationOpen AccessNubia-Eurasia kinematics: an alternative interpretation from Mediterranean and North Atlantic evidence(2007-04-03T14:49:52Z)
; ; ; ; ;Mantovani, E.; Dipartimento di Scienze della Terra, Università degli Studi di Siena ;Viti, M.; Dipartimento di Scienze della Terra, Università degli Studi di Siena ;Babbucci, D.; Dipartimento di Scienze della Terra, Università degli Studi di Siena ;Albarello, D.; Dipartimento di Scienze della Terra, Università degli Studi di Siena; ; ; It is argued that the Plio-Quaternary deformation pattern in the Mediterranean region is compatible with a SSW-NNE convergence between Africa (Nubia) and Eurasia and that the significant difference between this kinematics and the one provided by global models (SSE-NNW convergence, e.g., the NUVEL-1) may be due to the fact that those models interpret North Atlantic data by adopting an oversimplified two-plate configuration, which cannot account for the occurrence of significant seismotectonic activity inside the presumed Nubia and Eurasia blocks. It is shown that the adoption of a new plate configuration involving the Iberia and Morocco microplates, strongly suggested by geological and seismotectonic evidence, makes it possible to identify a kinematic model compatible within errors with the constraints recognized in the Mediterranean region and with the NUVEL-1 North Atlantic data set. Some considerations are made about the reason why the present-day Nubia-Eurasia kinematic models inferred from geodetic observations are significantly different from long-term models, such as model NUVEL-1 and the one proposed in this work.210 470 - PublicationOpen AccessTectonic interpretation of large scale geodetic measurements (VLBI, SLR) in the Central Mediterranean region: constraints and uncertainties(1995-03)
; ; ; ; ;Mantovani, E.; Dipartimento di Scienze della Terra, Geofisica, Università di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Geofisica, Università di Siena, Italy ;Tarnburelli, C.; Dipartimento di Scienze della Terra, Geofisica, Università di Siena, Italy ;Viti, M.; Dipartimento di Scienze della Terra, Geofisica, Università di Siena, Italy; ; ; Some considerations are reported on the tectonic setting and microplate mosaic in the Mediterranean zones where VLBI and SLR stations are located. In particular, the possible sources of ambiguity in the determination of the Africa-Eurasia and Adriatic-Eurasia relative motions from geodetic data are discussed. Possible alternative kinematic interpretations, with respect to those reported in the literature, are then proposed.151 535 - PublicationOpen AccessNubia-Eurasia kinematics: an alternative interpretation from Mediterranean and North Atlantic evidence(2007-06)
; ; ; ; ;Mantovani, E.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy ;Viti, M.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy ;Babbucci, D.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy; ; ; It is argued that the Plio-Quaternary deformation pattern in the Mediterranean region is compatible with a SSWNNE convergence between Africa (Nubia) and Eurasia and that the significant difference between this kinematics and the one provided by global models (SSE-NNW convergence e.g., the NUVEL-1) may be due to the fact that those models interpret North Atlantic data by adopting an oversimplified two-plate configuration, which cannot account for the occurrence of significant seismotectonic activity inside the presumed Nubia and Eurasia blocks. It is shown that the adoption of a new plate configuration involving the Iberia and Morocco microplates, strongly suggested by geological and seismotectonic evidence, makes it possible to identify a kinematic model compatible within errors with the constraints recognized in the Mediterranean region and with the NUVEL-1 North Atlantic data set. Some considerations are made about why the present-day Nubia-Eurasia kinematic models inferred from geodetic observations are significantly different from long-term models, such as model NUVEL- 1 and the one proposed in this work.260 668 - PublicationRestrictedPost-late miocene kinematics of the adria microplate: inferences from geological, geophysical and geodetic data(2006)
; ; ; ; ; ; ; ;Mantovani, E.; University of Siena, Italy ;Babbucci, D.; University of Siena, Italy ;Viti, M.; University of Siena, Italy ;Albarello, D.; University of Siena, Italy ;Mugnaioli, E.; University of Siena, Italy ;Cenni, N.; University of Bologna, Italy ;Casula, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; ; ; ; ; ; The space-time distribution of deformation in the central Mediterranean area suggests that the Adriatic domain (Adria) has moved coherently w~thA frica up until the late Miocene and that, subsequently, it decoupled fiom Africa (Nubia) and undenvcnt a clockwise (CW) rotation with respect to Eurasia. This event was determined by the wcstward push of the Anatolian- Aegean-Balkan system, after its collision with the southern Adriatic continental domain. The CW rotation of the Adria microplate induced a strong compressional regime in the central Mediterranean region, which can account for the major tectonlc events that occurred in this zone since the late Miocene. These include the renewal of accretionary activity in the Apenninic belt, the opening of the central Tyrrhenian basin, the detachment of the lblean microplate from mainland Africa and the development of a major fracture in the northern Adriatic foreland. The CW rotation of the Adria plate came to an end around the late Pliocene-early Pleistocene due to the collision of the Adria continental domain with the Southern Apennines. After this event, Adria has undergone a slow CCW rotation with respect to Eurasia. This kinematic pattern during the last evolutionary phase is suggested by the distribution of Quaternary deformation in the peri-Adnatic zones, in particular the shortening recognized at the eastern (Dinarides-Hellenides) and northern (southern Eastern Alps) boundaries of Adria, and is consistent with the seismological and geodetic evidence in the Adriatic and peri-Adriatic regions. No significant recent deformation can be recognized between Adria and Africa, at the Plioccnc decoupling zone or at any other possible decoupling tectonic belt. This suggests no, or at most very littlc, rclative motion bctwcen thew two doma~ns during the Quaternary. Tlic possible implications of this last evidence on Nubia-Eurasia kinematics are discussed.203 34 - PublicationOpen AccessFinite element modelling of the recent- present deformation patter in the Calabrian arc and surrounding regions(1997-08)
; ; ; ;Albarello, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Mantovani, E.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Viti, M.; Dipartimento di Scienze della Terra, Università di Siena, Italy; ; An attempt is made to quantify the implications of the hypothesis that the recent-present deformation pattem in the Calabrian arc and the adjacent African margin is mainly determined by horizontal tectonic forces in- duced by the relative convergence of the confining blocks (Africa and Adriatic)- Modelling of present-day tec- tonic processes is carried out by means of a 2D finite element scheme involving elastic shells in a piane stl-ess approximation- On the assumption that tectonic processes are strongly influenced by the presencc of major di,- continuitie", the model includes zones whcre most deformations can concentl-ate Convcrgent and divcrgcnt boundaries are simulated by narrow belts having elastic parameters lower than those in the surrounding regions, transform boundaries are reproduced by orthotl-opic elements, Kinematic boundary conditions are im- po,ed to simulatc the relative convergence between Africa and the Adriatic, Numerical experimcnts show that this convergence causes the lateral escape of crustal wedgcs in the Calabrian arc and the adjacent African mar- gin (Sjcily). The resulting microplate kinematics can account for the complex distribution of compressional, tensional and transcurrent deformations actually observed.155 377 - PublicationOpen AccessTentative list of major deformation events in the Central-Eastern Mediterranean region since the middle Miocene(1997-06)
; ; ; ; ;Babbucci, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Tamburelli, C.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Mantovani, E.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy; ; ; A list of major constraints to impose on evolutionary reconstructions of the Central-Eastern Mediterranean region for the middle Miocene period to the Present is proposed. Each constraint is constituted by a tentative description of the deformation and related tectonic regime which affected major active zones during each evolutionary phase. This information has been derived from the analysis of the available observations in the various branches of Earth Sciences, trying to select clearly recognized deformations, possibly supported by independent observations. The list here reported has been used to constrain the evolutionary reconstruction proposed by Mantovani et al.(1997).182 367 - PublicationOpen AccessQuantitative insights into the role of gravitational collapse in major orogenic belts(2006-11-17T10:00:33Z)
; ; ; ;Viti, M.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy ;Mantovani, E.; Dipartimento di Scienze della Terra, Università degli Studi di Siena, Italy; ; Abstract Previous works have proposed gravitational collapse as the driving mechanism of extensional deformation of thickened continental crust. In this work we investigate the physical plausibility of this interpretation for the most important orogenic belts of the world by computing the spreading force induced by lateral variations of crustal thickness and the possible resisting forces. Two collapse mechanisms, one involving the upper crust only and the other the whole crust, have been considered. Particular attention has been devoted to constrain the uncertainty affecting such computations, mostly due to the large variability of the thermal and mechanical properties of rocks. The results obtained show that gravitational collapse is not a plausible mechanism in the four Mediterranean orogens here considered (Northern Apennines, Calabrian Arc, Hellenic Arc and Carpathians). For the other orogenic zones we have taken into account (Western U.S. Cordillera, Central Andes, Himalayas and Central Alps), the large uncertainty that affects the estimate of spreading and resisting forces does not allow to firmly assess the feasibility of gravitational collapse.216 571 - PublicationOpen AccessRheological profiles in the Central- Eastern Mediterranean(1997-08)
; ; ; ;Viti, M.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Mantovani, E.; Dipartimento di Scienze della Terra, Università di Siena, Italy; ; Seismological investigations have provided an estimate of the gross structnral features of the crust/upper mantle system in the Mediterranean area. However, this information is only representative of the short-term me- chanical behaviour of rocks and cannot help us to understand slow deformations and related tectonic processes on the geological time scale. In this work strength envelopes for several major structural provinces of the Mediterranean area have been tentatively derived from seismological stratification and heat flow data, on the assumption of constant and uniforrn strain rate (10-16 S-1), wet rocks and conductive geotherm. It is also shown how the uncertainties in the reconstruction of thermal profiles can influence the main rheological prop- erties of the lithosphere, as thickness and total strength. The thickest (50-70 km) and strongest mechanical lithospheres correspond to the coldest zones (with heat flow lower than or equal to 50 mW m-2), i.e., the Io- nian and Levantine mesozoic basins, the Adriatic and Eurasian foreland zones and NW Greece. Heat flows larger than 65 mW m-2, generally observed in extensional zones (Tyrrhenian, Sicily Channel, Northern Aegean, Macedonia and Western Turkey), are mostly related to mechanical lithospheres thinner than 20 km. The characteristics of strength envelopes, and in particular the presence of soft layers in the crust, suggest a reasonable interpretation of some large-scale features which characterize the tectonic evolution of the Central- Eastem Mediterranean.188 509 - PublicationOpen AccessRecognizing the Italian zones most prone to next large earthquakes: possible approaches and present chances(1997-10)
; ; ; ; ;Mantovani, E.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Albarello, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Tamburelli, C.; Dipartimento di Scienze della Terra, Università di Siena, Italy ;Babbucci, D.; Dipartimento di Scienze della Terra, Università di Siena, Italy; ; ; The defense from earthquakes in Italy would be considerably favoured by knowing where the next strong shocks will most probably occur. However, to obtain this information a well-defined and widely accepted method is not yet available. This work discusses the approaches so far proposed and tries to estimate the relative chances of providing reliable indications on this problem. Particular attention focusses on the methodology based on the concept of «strain migration».139 139