Starting from middle Miocene, the inner sector of the Calabria Arc (southern Italy) was characterised by the deposition of clastic sedimentary sequences, unconformably lying on the orogenic nappe edifice. Still debated is the interpretation of the tectonic context controlling sedimentation in Mio-Pleistocene times and different tectonic models have been proposed: (i) models considering the clastic successions as filling piggy-back or perched basins during the eastward migrating Apennine compressional phases; (ii) models invoking a late Miocene compressive tectonic inversion of an early extensional tectonic phase; and (iii) models proposing the continuous control of extensional processes on the formation and evolution of the tectonic depressions filled by sedimentary sequences. An integrated structural and paleomagnetic study has been carried out on the middle Miocene-Pleistocene sediments filling the Crati basin, northern Calabria. Extensive paleomagnetic sampling of 35 sites has been performed in the clay deposits of distinct ages cropping out throughout the basin. Reliable paleomagnetic data were gathered from 29 sites.Structural and AMS data showed that extensional tectonics was the main factor controlling basin formation and evolution. No evidence for compressional deformation was recognised and it is reasonable to infer that Tyrrhenian extension was a continuous process, active in Calabria since Middle Miocene onward. Paleomagnetic results provide evidence for a differential tectonic evolution occurred in the Crati Basin. The southern sector underwent a homogeneous 25° clockwise rotation. In the central sector of the basin, paleomagnetic vectors show different sense and amount of rotations and altogether, reveal for this sector small scale rotations related to faults bounded blocks. The northern sector is, on the contrary, characterised by a 20° anti-clockwise rotation. These data suggest that this area underwent a complex tectonic evolution during crustal extension and can not be considered tectonically homogeneous. Moreover, evaluation of the deformation history of this area has to take into account the local control exerted by tectonic structures inducing rotation on fault bounded blocks and the influence of the time-space migration of the fault activity.
Cifelli, F., Mattei, M., Rossetti, F. (2004). Paleomagnetism of the Neogene-Quaternary sequences of the Crati Basin (Calabria, Southern Italy): tectonic implications.
Paleomagnetism of the Neogene-Quaternary sequences of the Crati Basin (Calabria, Southern Italy): tectonic implications
CIFELLI, FRANCESCA;MATTEI, Massimo;ROSSETTI, FEDERICO
2004-01-01
Abstract
Starting from middle Miocene, the inner sector of the Calabria Arc (southern Italy) was characterised by the deposition of clastic sedimentary sequences, unconformably lying on the orogenic nappe edifice. Still debated is the interpretation of the tectonic context controlling sedimentation in Mio-Pleistocene times and different tectonic models have been proposed: (i) models considering the clastic successions as filling piggy-back or perched basins during the eastward migrating Apennine compressional phases; (ii) models invoking a late Miocene compressive tectonic inversion of an early extensional tectonic phase; and (iii) models proposing the continuous control of extensional processes on the formation and evolution of the tectonic depressions filled by sedimentary sequences. An integrated structural and paleomagnetic study has been carried out on the middle Miocene-Pleistocene sediments filling the Crati basin, northern Calabria. Extensive paleomagnetic sampling of 35 sites has been performed in the clay deposits of distinct ages cropping out throughout the basin. Reliable paleomagnetic data were gathered from 29 sites.Structural and AMS data showed that extensional tectonics was the main factor controlling basin formation and evolution. No evidence for compressional deformation was recognised and it is reasonable to infer that Tyrrhenian extension was a continuous process, active in Calabria since Middle Miocene onward. Paleomagnetic results provide evidence for a differential tectonic evolution occurred in the Crati Basin. The southern sector underwent a homogeneous 25° clockwise rotation. In the central sector of the basin, paleomagnetic vectors show different sense and amount of rotations and altogether, reveal for this sector small scale rotations related to faults bounded blocks. The northern sector is, on the contrary, characterised by a 20° anti-clockwise rotation. These data suggest that this area underwent a complex tectonic evolution during crustal extension and can not be considered tectonically homogeneous. Moreover, evaluation of the deformation history of this area has to take into account the local control exerted by tectonic structures inducing rotation on fault bounded blocks and the influence of the time-space migration of the fault activity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
