Skip to Main content Skip to Navigation
Journal articles

Subduction zone intermediate-depth seismicity: Insights from the structural analysis of Alpine high-pressure ophiolite-hosted pseudotachylyte (Corsica, France)

Abstract : Pseudotachylyte in the Cima di Gratera ophiolite, Alpine Corsica, is distributed in the peridotite unit and in the overlying metagabbro unit and was formed under blueschist to eclogite metamorphic facies conditions, corresponding to a 60–90 km depth range. Peridotite pseudotachylyte is clustered in fault zones either beneath the tectonic contact with overlying metagabbros or at short distance from it. Fault zones are either parallel to the contact or make an angle of 55° to it. Displacement sense criteria associated with fault veins indicate top-to-the-west or top-to-the-northwest reverse senses. Cataclasite flanking most veins was formed before or coevally with frictional melting and likely mechanically weakened the peridotite, facilitating subsequent seismic rupture. In the basal part of the metagabbro unit, post-mylonitization pseudotachylyte can be distinguished from pre-mylonitization pseudotachylyte formed earlier. In the equant metagabbro above the mylonitic sole, only one episode of pseudotachylyte formation can be identified. Kinematics associated with metagabbro pseudotachylyte remain unknown. The geometry and kinematics of the pseudotachylyte veins from the peridotite unit and to a lesser extent from the metagabbro unit are similar to modern seismic ruptures of the upper parts of the Wadati-Benioff zones such as in the Pacific plate beneath NE Japan.
Document type :
Journal articles
Complete list of metadata

Cited literature [3 references]  Display  Hide  Download

https://hal.sorbonne-universite.fr/hal-01346160
Contributor : Gestionnaire Hal-Upmc <>
Submitted on : Monday, July 18, 2016 - 2:03:00 PM
Last modification on : Tuesday, December 8, 2020 - 3:41:47 AM

File

Magott_2016_Subduction_zone.pd...
Files produced by the author(s)

Identifiers

Citation

Rémi Magott, Olivier Fabbri, Marc Fournier. Subduction zone intermediate-depth seismicity: Insights from the structural analysis of Alpine high-pressure ophiolite-hosted pseudotachylyte (Corsica, France). Journal of Structural Geology, Elsevier, 2016, 87, pp.95-114. ⟨10.1016/j.jsg.2016.04.002⟩. ⟨hal-01346160⟩

Share

Metrics

Record views

469

Files downloads

448