3-D Pn tomography reveals continental subduction at the boundaries of the Adriatic microplate in the absence of a precursor oceanic slab

Sun, Weijia; Zhao, Liang; Malusà, Marco G.; Guillot, Stéphane; Fu, Li‐Yun

doi:10.1016/j.epsl.2019.01.012

Cited by 27 publications

(38 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1b). The deep configuration of this subduction wedge is increasingly well documented by geophysical data [14][15][16][17][18][19][20][21][22] , but a high-resolution image of seismic velocity structure for the deepest levels of the plate interface is still missing. As a consequence, potential rheology variations within the subduction channel remain largely unconstrained, which precludes a full understanding of the dynamics of crucial stages of continental subduction and exhumation of UHP rocks.…”

mentioning

confidence: 99%

Evidence for a serpentinized plate interface favouring continental subduction

Yuan¹,

Lu²,

Stehly³

et al. 2020

Nat Commun

Self Cite

View full text Add to dashboard Cite

The dynamics of continental subduction is largely controlled by the rheological properties of rocks involved along the subduction channel. Serpentinites have low viscosity at geological strain rates. However, compelling geophysical evidence of a serpentinite channel during continental subduction is still lacking. Here we show that anomalously low shear-wave seismic velocities are found beneath the Western Alps, along the plate interface between the European slab and the overlying Adriatic mantle. We propose that these seismic velocities indicate the stacked remnants of a weak fossilised serpentinite channel, which includes both slivers of abyssal serpentinite formed at the ocean floor and mantle-wedge serpentinite formed by fluid release from the subducting slab. Our results suggest that this serpentinized plate interface may have favoured the subduction of continental crust into the upper mantle and the formation/exhumation of ultra-high pressure metamorphic rocks, providing new constraints to develop the conceptual and quantitative understanding of continentalsubduction dynamics.

show abstract

mentioning

confidence: 99%

Evidence for a serpentinized plate interface favouring continental subduction

Yuan¹,

Lu²,

Stehly³

et al. 2020

Nat Commun

Self Cite

View full text Add to dashboard Cite

show abstract

“…() and Sun et al. (), with particular emphasis on the attitude of the European slab and the role of the slab edge formed by vertical tearing. As shown in Figure c, the middle Eocene zircon U–Pb ages reported in the Traversella pluton demonstrate that magmatism started synchronously in the Western and Central Alps.…”

Section: Discussionmentioning

confidence: 99%

“…() (simplified after Sun. et al., ). The European slab edge, indicated by the green arrow, may result from vertical tearing of the Alpine slab after the onset of Dinaric subduction [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Geologic Backgroundmentioning

confidence: 99%

“…(), interpret the deep velocity anomaly beneath the Eastern Alps as stemming from an oceanic and detached slab. Recent and higher resolution tomography models that benefited from the opening of the European seismic databases (Sun, Zhao, Malusà, Guillot, & Fu, ; Zhao et al., ) depict a more complex interaction between the Alpine and Dinaric slabs (Figure d), and suggest the presence of a slab edge to the east of the Adamello batholith. Based on available tomographic and plate motion constraints (Figure ), we suggest that this slab edge may have formed by vertical tearing of the Alpine slab in the Eocene, after the onset of Dinaric subduction.…”

Section: Geologic Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

Synchronous Periadriatic magmatism in the Western and Central Alps in the absence of slab breakoff

Malusà

Tiepolo

et al. 2019

Terra Nova

Self Cite

View full text Add to dashboard Cite

Periadriatic Alpine magmatism has long been attributed to slab breakoff after Adria-Europe continental collision, but this interpretation is challenged by geophysical data suggesting the existence of a continuous slab. Here, we shed light on this issue based on a comprehensive dataset of zircon U-Pb ages and Hf isotopic compositions from the main western Periadriatic intrusives (from Traversella to Adamello). Our zircon U-Pb data provide the first evidence of Eocene magmatism in the Western Alps (42-41 Ma in Traversella), and demonstrate that magmatism started synchronously in different segments of the Alpine belt, when subduction was still active. Zircon U-Pb ages define younging trends perpendicular to the strike of the European slab, suggesting a progressive Eocene-Oligocene slab steepening. We propose that slab steepening enhanced the corner flow. This process was more effective near the torn edge of the European slab, and triggered Periadriatic magmatism in the absence of slab breakoff.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

“…The western Alpine region (Figures 1a and 1d) is located at the transition between the opposite‐dipping Alpine and Apenninic slabs (Piromallo & Morelli, 2003; Sun et al, 2019; Zhao et al, 2016). It shows relatively minor seismicity (Chiarabba et al, 2005; Giardini et al, 1999) due to slow convergence between tectonic plates (Sánchez et al, 2018; Serpelloni et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Seismotectonics at the Transition Between Opposite‐Dipping Slabs (Western Alpine Region)

2020

Self Cite

View full text Add to dashboard Cite

We analyze a fully reprocessed data set of~9,000 seismic events recorded in the western Alpine region during the past 30 yr, in order to understand how convergence between Africa and Eurasia is presently accommodated at the transition between the opposite-dipping Alpine and Apenninic slabs. We confirm that seismicity in the Internal Zone of the Western Alps is clustered along two different arcs (Briançonnais and Piedmont arcs), clearly outlined by events in the 0-12 km depth range. The Piedmont Arc is best outlined by events in the 12-30 km depth range, forming a narrow belt that matches the shape and location of the Ivrea gravity anomaly. In the Internal Zone, σ 3 , is oblique to the orogen trend. Although the mountain range is spreading gravitationally at a shallow level, spreading occurs intermittently with other earthquakes that are more directly related to plate interactions. Strike-slip solutions are predominant for events of magnitude M l > 4, and reverse solutions are dominant along the Piedmont Arc for events of magnitude M l < 4. Nodal planes have dominant NNW-SSE and ENE-WSW orientations that are common to major faults mapped in the study area. Integration with available tectonic and geodynamic constraints indicates that lithology distribution in the subduction wedge, orientation of major faults within and outside the subduction zone, and the exhumation of mantle rocks at shallow depth concurrently determine a complex seismotectonic scenario that may be expected in other subduction zones worldwide.

show abstract

3-D Pn tomography reveals continental subduction at the boundaries of the Adriatic microplate in the absence of a precursor oceanic slab

Cited by 27 publications

References 47 publications

Evidence for a serpentinized plate interface favouring continental subduction

Evidence for a serpentinized plate interface favouring continental subduction

Synchronous Periadriatic magmatism in the Western and Central Alps in the absence of slab breakoff

Seismotectonics at the Transition Between Opposite‐Dipping Slabs (Western Alpine Region)

Contact Info

Product

Resources

About