Seismic anisotropy in the Hellenic subduction zone: Effects of slab segmentation and subslab mantle flow

Evangelidis, Christos

doi:10.1016/j.epsl.2017.10.003

Cited by 32 publications

(42 citation statements)

References 53 publications

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“…If this is the case, our observed anisotropy may reflect active mantle flow in the asthenosphere. Previous SKS splitting studies have revealed NE‐SW FPDs beneath the south‐central Aegean, which are attributed to mantle flow caused by retreat of the subducting slab (Evangelidis, ; Olive et al, ). Our results suggest that the anisotropy is weak in south‐central Aegean (Figure a), which is consistent with the SKS splitting measurements showing that the delay times are generally small in this region.…”

Section: Discussionmentioning

confidence: 99%

“…Studying seismic anisotropy, therefore, can provide important constraints on geodynamics of subduction zones and continental collision zones (e.g., Long 2013;Savage, 1999;Silver, 1996;Zhao et al, 2016). In the Eastern Mediterranean and Middle East, previous anisotropic studies mainly rely on the shear wave splitting analysis (e.g., Biryol et al, 2010;Evangelidis, 2017;Hatzfeld et al, 2001;Kaviani et al, 2009;Olive et al, 2014;Paul et al, 2014) and surface wave inversion (e.g., Endrun et al, 2011). However, due to the poor vertical resolution of the shear wave splitting method, it is still debated on whether the observed azimuthal anisotropy occurs in the lithospheric mantle or asthenosphere.…”

Section: -D Seismic Anisotropy and Mantle Flowmentioning

confidence: 99%

“…In the Hellenic subduction zone, results of SKS splitting studies suggest that the FPD is trench-parallel in the forearc and trench-normal in the back-arc (Evangelidis, 2017;Evangelidis et al, 2011;Olive et al, 2014). The anisotropy in the back-arc is widely accepted to be caused by poloidal flow driven by the retreat of the subducting Hellenic slab (Evangelidis, 2017;Olive et al, 2014), whereas there are different views on the source of observed anisotropy in the forearc, including the supra-slab (Olive et al, 2014), slab itself (Faccenna et al, 2014), and subslab mantle (Evangelidis, 2017). Our Vp anisotropic tomography reveals prominent FVD variations in the upper mantle beneath the forearc and back-arc Aegean region (Figures 6a and 6b).…”

Section: -D Seismic Anisotropy and Mantle Flowmentioning

confidence: 99%

“…In addition, we need to point out that although both the slab and mantle wedge show trench-parallel FVD features beneath the forearc region, the anisotropy may have several sources in the wide region, because we can only resolve regionalscale anisotropic features in this study. Therefore, local-scale tomographic studies are required to better constrain the anisotropy in the slab, mantle wedge and the overriding plate, which have already been made for the Japan subduction zone (e.g., Huang et al, 2011;, 2017Niu et al, 2016;Wang et al, 2017;Wang et al, 2019).…”

Section: Geochemistry Geophysics Geosystemsmentioning

confidence: 99%

“…In the eastern Mediterranean, seismic anisotropy in the upper mantle is primarily constrained by shear wave splitting analysis of the core‐refracted phases such as SKS and SKKS (Silver & Chan, ; Vinnik et al, ). Previous results show that in the Aegean back‐arc basin and Anatolia, the fast polarization directions (FPDs) are almost consistent, being NE‐SW to NNE‐SSW (Biryol et al, ; Evangelidis, ; Olive et al, ; Paul et al, ), while in the trench‐forearc regions, the FPDs are much more complex but exhibit a roughly trench‐parallel FPD pattern (Evangelidis, ; Olive et al, ). Because SKS splitting is a path‐integrated measurement, its vertical resolution is poor, and so the origin of anisotropy cannot be well constrained and remains hotly debated.…”

Section: Introductionmentioning

confidence: 97%

See 4 more Smart Citations

Mantle Dynamics of the Eastern Mediterranean and Middle East: Constraints From P‐Wave Anisotropic Tomography

Wei

Zhao

Wei

et al. 2019

Geochem Geophys Geosyst

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High‐resolution images of P‐wave anisotropic tomography beneath the Eastern Mediterranean and Middle East are determined by inverting a large number of high‐quality P‐wave arrival times. Our results clearly show along‐strike variations of subducting slabs in the Hellenic subduction zone. At least three high‐velocity anomalies are imaged beneath and behind the north Hellenides, which are associated with the subducting Hellenic slab at different stages, while in regions further south, a single slab is revealed that has subducted down to a depth of ~1,100 km. The slab feature is not prominent in the Cyprus subduction zone, but a fine‐scale high‐velocity structure is revealed beneath the central Anatolia, which may reflect the detached Cyprus slab. Trench‐parallel fast‐velocity directions occur in the forearc mantle wedge of the Hellenic subduction zone, which may reflect mantle flow induced by slab curvature. In the backarc north Aegean and westernmost Anatolia, dominant NNE‐SSW to N‐S fast‐velocity directions exist in the shallow mantle, which accord well with the extensional direction of present deformation at the surface, suggesting a vertically coherent deformation in the lithosphere. Our results reveal a large‐scale mantle flow beneath western Arabia, which is possibly related to the Zagros and Caucasus orogens and westward motion of the Anatolia lithosphere. The Arabian lithospheric plate is thinner beneath the Zagros than that under the Mesopotamian Foredeep, suggesting that a large portion of the crust was scrapped off from the subducted Arabian lithosphere during the Zagros orogen.

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Section: Discussionmentioning

confidence: 99%

Section: -D Seismic Anisotropy and Mantle Flowmentioning

confidence: 99%

Section: -D Seismic Anisotropy and Mantle Flowmentioning

confidence: 99%

Section: Geochemistry Geophysics Geosystemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Mantle Dynamics of the Eastern Mediterranean and Middle East: Constraints From P‐Wave Anisotropic Tomography

Wei

Zhao

Wei

et al. 2019

Geochem Geophys Geosyst

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A Review of the Dynamics of Subduction Zone Initiation in the Aegean Region

Catlos

Çemen

2023

Compressional Tectonics

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A Review of the Dynamics of Subduction Zone Initiation in the Aegean Region

Catlos

Çemen

2021

Preprint

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The Hellenic arc, where the African (Nubian) slab subducts beneath the Aegean and Anatolian microplates, has emerged as a type-locality for understanding subduction dynamics, including slab tear, slab fragments, drips, and transfer zones. Based on field evidence and geophysical, tectonics, and geochemical studies, it has been recognized that the subducting African slab is a primary driver for extension in the Aegean and Anatolian microplates and plays a significant role in accommodating present-day westward extrusion of the Anatolian microplate. Thus, understanding the Hellenic arc subduction zone initiation (SZI) age is critical in deciphering ancient mantle flow, how plate tectonics is maintained, and the mechanisms involved in triggering the onset of subduction. The SZI for the Hellenic arc has two disparate ages based on different lines of evidence. A Late Cenozoic (Eocene-Pliocene) SZI is proposed using the analysis of topography combined with estimates of slab age and depth, paleomagnetism, the timing of metamorphism, and volcanic activity, and timing of sedimentation within its accretionary wedge, the Mediterranean Ridge. This age follows an induced-transference SZI model, where a new subduction zone initiates following the jamming of an older subduction zone by buoyant crust due to regional compression, uplift, and underthrusting. A Late Cretaceous-Jurassic SZI age has also been proposed using reconstructions of images of subducted slabs seen using tomography and timing of obducted ophiolite fragments thought to be related to the system. In this case, the induced-transference SZI model fails, and a single subduction zone persists. As a result, continental lithospheric fragments and the ancient oceans between them become incorporated into the overall system without creating a new subduction zone. The presence of a long-lived subduction zone has implications for understanding Earth's mantle dynamics and how plate tectonics operates. This paper describes and summarizes the evidence for both models in the Aegean-Western Anatolia region.

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Seismic anisotropy in the Hellenic subduction zone: Effects of slab segmentation and subslab mantle flow

Cited by 32 publications

References 53 publications

Mantle Dynamics of the Eastern Mediterranean and Middle East: Constraints From P‐Wave Anisotropic Tomography

Mantle Dynamics of the Eastern Mediterranean and Middle East: Constraints From P‐Wave Anisotropic Tomography

A Review of the Dynamics of Subduction Zone Initiation in the Aegean Region

A Review of the Dynamics of Subduction Zone Initiation in the Aegean Region

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