The first discovery of ultrahigh-pressure coesite in the European Alps 30 years ago led to the inference that a positively buoyant continental crust can be subducted to mantle depth; this had been considered impossible since the advent of the plate tectonics concepts. Although continental subduction is now widely accepted, there remains debate because there is little direct (geophysical) evidence of a link between exhumed coesite at the surface and subducted continental crust at depth. Here we provide the first seismic evidence for continental crust at 75 km depth that is clearly connected with the European crust exactly along the transect where coesite was found at the surface. Our data also provide evidence for a thick suture zone with downward-decreasing seismic velocities, demonstrating that the European lower crust underthrusts the Adriatic mantle. These findings, from one of the best-preserved and long-studied ultrahigh-pressure orogens worldwide, shed decisive new light on geodynamic processes along convergent continental margins.

Zhao, L., Paul, A., Guillot, S., Solarino, S., Malusa', M., Zheng, T., et al. (2015). First seismic evidence for continental subduction beneath the Western Alps. GEOLOGY, 43(9), 815-819 [10.1130/G36833.1].

First seismic evidence for continental subduction beneath the Western Alps

MALUSA', MARCO GIOVANNI;
2015

Abstract

The first discovery of ultrahigh-pressure coesite in the European Alps 30 years ago led to the inference that a positively buoyant continental crust can be subducted to mantle depth; this had been considered impossible since the advent of the plate tectonics concepts. Although continental subduction is now widely accepted, there remains debate because there is little direct (geophysical) evidence of a link between exhumed coesite at the surface and subducted continental crust at depth. Here we provide the first seismic evidence for continental crust at 75 km depth that is clearly connected with the European crust exactly along the transect where coesite was found at the surface. Our data also provide evidence for a thick suture zone with downward-decreasing seismic velocities, demonstrating that the European lower crust underthrusts the Adriatic mantle. These findings, from one of the best-preserved and long-studied ultrahigh-pressure orogens worldwide, shed decisive new light on geodynamic processes along convergent continental margins.
Articolo in rivista - Articolo scientifico
Continental subduction, exhumation, deep structure, Western Alps
English
2015
43
9
815
819
reserved
Zhao, L., Paul, A., Guillot, S., Solarino, S., Malusa', M., Zheng, T., et al. (2015). First seismic evidence for continental subduction beneath the Western Alps. GEOLOGY, 43(9), 815-819 [10.1130/G36833.1].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/107556
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