The central Southern Alps retrobelt was built trough a polyphase tectonic evolution that developed in the hangingwall of the SE-directed Alpine Tethys subduction. In the northern sector of the central Southern Alps the earliest stages of shortening resulted in the inversion of structures inherited from the Permian and Triassic rifting phases, together with southward thrusting and large-scale folding. In the San Marco Pass area (N Italy) the Variscan basement overrides the Permian-Triassic sedimentary cover along regional thrusts. Here the E-W trending Orobic Thrust joins the NE-SE Porcile Thrust. Initial thrusting phases formed greenschist facies mylonites in the basement and S-verging folds in the sedimentary covers. The Porcile line, a feature likely inherited from the Permian extension, was re-activated as a steep mylonite shear zone. Fault activity continued at brittle conditions: cataclastic shear zones overprinted the mylonites. During this phase, shortening was preferentially accommodated along the Orobic Thrust. A final transpressive re-activation observed along both thrusts is linked to the Oligocene activity of the Insubric Fault.

D'Adda, P., Zanchetta, S. (2015). Geological-structural map of the Orobic and Porcile thrust junction, central Southern Alps (N Italy). JOURNAL OF MAPS, 11(1), 25-38 [10.1080/17445647.2014.944944].

Geological-structural map of the Orobic and Porcile thrust junction, central Southern Alps (N Italy)

D'ADDA, PAOLO
Primo
;
ZANCHETTA, STEFANO
Ultimo
2015

Abstract

The central Southern Alps retrobelt was built trough a polyphase tectonic evolution that developed in the hangingwall of the SE-directed Alpine Tethys subduction. In the northern sector of the central Southern Alps the earliest stages of shortening resulted in the inversion of structures inherited from the Permian and Triassic rifting phases, together with southward thrusting and large-scale folding. In the San Marco Pass area (N Italy) the Variscan basement overrides the Permian-Triassic sedimentary cover along regional thrusts. Here the E-W trending Orobic Thrust joins the NE-SE Porcile Thrust. Initial thrusting phases formed greenschist facies mylonites in the basement and S-verging folds in the sedimentary covers. The Porcile line, a feature likely inherited from the Permian extension, was re-activated as a steep mylonite shear zone. Fault activity continued at brittle conditions: cataclastic shear zones overprinted the mylonites. During this phase, shortening was preferentially accommodated along the Orobic Thrust. A final transpressive re-activation observed along both thrusts is linked to the Oligocene activity of the Insubric Fault.
Articolo in rivista - Articolo scientifico
alpine deformation; central Southern Alps; fault slip data; structural analysis; Earth and Planetary Sciences (miscellaneous); Geography, Planning and Development
English
2015
11
1
25
38
none
D'Adda, P., Zanchetta, S. (2015). Geological-structural map of the Orobic and Porcile thrust junction, central Southern Alps (N Italy). JOURNAL OF MAPS, 11(1), 25-38 [10.1080/17445647.2014.944944].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/138152
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