Seismic tomography reveals contrasting styles of subduction-channel and mantle-wedge exhumation controlled by upper plate divergent motion - Archive ouverte HAL
Article Dans Une Revue Gondwana Research Année : 2024

Seismic tomography reveals contrasting styles of subduction-channel and mantle-wedge exhumation controlled by upper plate divergent motion

Résumé

In fossil subduction zones associated with massive exhumation of (ultra)high-pressure ((U)HP) rocks such as the Western Alps, the geometry and behavior of subduction-channel and mantle-wedge rocks during exhumation are still poorly constrained by independent geophysical observations. Here we use a new local earthquake tomography model of the entire fossil subduction zone of the Western Alps based on data collected during the CIFALPS and CIFALPS2 passive seismic experiments, and the first receiver- function profile across the Ligurian Alps, to investigate the styles of subduction-channel and mantle- wedge exhumation as a function of increasing upper-plate divergence motion. In the northern Western Alps (low divergence), a thickened subduction channel can be detected, but no exhumed mantle wedge is found beneath the Gran Paradiso (U)HP dome. In the southern Western Alps (intermediate divergence), an exhumed mantle wedge is detected beneath the Dora-Maira (U)HP dome above a serpen- tinized subduction channel. In the Ligurian Alps (high divergence), an exhumed mantle wedge and a for- mer subduction channel are detected at much shallower levels beneath the Voltri-Valosio (U)HP dome, and above a shallow-dipping lower-plate Moho. In this latter case, the lower boundary of the exhumed subduction channel is the most evident seismic-velocity interface, which may be easily misinterpreted as a true Moho. Similar Moho-like interfaces are found beneath the exhumed (U)HP domes of eastern Papua New Guinea and the Dabie Shan, which suggests that the results of the CIFALPS experiments may be used as a reference case for the interpretation of other (U)HP terranes worldwide.
Fichier principal
Vignette du fichier
1-s2.0-S1342937X2400265X-main.pdf (5.81 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte
Licence

Dates et versions

hal-04778829 , version 1 (14-11-2024)

Licence

Identifiants

Citer

Stefano Solarino, Marco Malusà, Elena Eva, Anne Paul, Stephane Guillot, et al.. Seismic tomography reveals contrasting styles of subduction-channel and mantle-wedge exhumation controlled by upper plate divergent motion. Gondwana Research, 2024, 136, pp.169-182. ⟨10.1016/j.gr.2024.08.016⟩. ⟨hal-04778829⟩
45 Consultations
7 Téléchargements

Altmetric

Partager

More