The effects of subduction termination on the continental lithosphere: Linking volcanism, deformation, surface uplift, and slab tearing in central Anatolia

Abstract

Subduction beneath central Anatolia represents the transition between continuous subduction along the Aegean trench in the west and slab break-off and/or subduction termination at the Arabian-Eurasian collision zone in the east. Using recently collected seismic data from the Continental Dynamics-Central Anatolian Tectonics project alongside a newly developed approach to the creation of a 3D shear-velocity model from the joint inversion of receiver functions and surface-wave dispersion data, we can gain important insights into the character of the downgoing, segmenting African lithosphere and its relationship with the overriding Central Anatolian plate. These results reveal that the mantle lithosphere of central Anatolia is thin and variable (<50-80 km) due to the decoupling of the crust of accreted lithospheric blocks from their associated lithospheric mantle, which continued to subduct and was subsequently removed by slab delamination during early-mid Miocene times. The resulting lithospheric thickness variations appear to control deformation as well as the distribution of vol canism throughout the region. In the Central Anatolian Volcanic Province, the upper most mantle is characterized by very slow shear velocities (<4.2 km/s) consistent with the presence of melt in the uppermost mantle. The fastest shear velocities observed in this study (>4.5 km/s) underlie the Central Taurus Mountains, which have experienced ~2 km of uplift in the past ~8 m.y. These velocities are consistent with lithospheric mantle, and we interpret that the recent uplift of these mountains is due to a rebound of the subducting slab after slab break-off and/or fragmentation rather than asthenospheric influx.

Sedimentation and viscosity controls on forearc highs

“…The latter mechanism is consistent with the thick Anatolian crust and lithosphere and the presence of the Cyprus slab under the modern Central Taurus Mountains (e.g., Bakırcı et al, 2012;Abgarmi et al, 2017;Delph et al, 2017) and the coupled, short-wavelength vertical motions reported for South Turkey and its offshore during plateau margin growth (Walsh-Kennedy et al, 2014;Fernández-Blanco et al, 2019).…”

“…We integrated tectono-sedimentary and interpreted geophysical data from on-and offshore studies in a crustal transect running from the Cyprus trench to Central Turkey ( (Robertson, 1998;Stephenson et al, 2004;Calon et al, 2005aCalon et al, , 2005bÇıner et al, 2008;McCay, 2010;Fernández-Blanco et al, 2013) with the interpretation of several geophysical studies (Ates et al, 1999;Mart & Ryan, 2002;Ergün et al, 2005;Koulakov & Sobolev, 2006;Özeren & Holt, 2010;Mutlu & Karabulut, 2011;Abgarmi et al, 2017;Delph et al, 2017), as detailed in Fernández-Blanco (2014). CVP = Central Volcanic Province.…”

Monoclinal flexure of an orogenic plateau margin during subduction, south Turkey

“…Contraction at depth, crustal thickening and monocline growth are also compatible with the presence of the Central Cyprus slab, and the thick crust below the modern Central Taurides relative to the Central Anatolia Plateau interior (e.g. Bakırcı et al, ; Abgarmi et al, ; Delph et al, ; Portner et al, ). By contrast, alternative models proposing plateau margin uplift by shallow slab break‐off during a multi‐phase evolution (Cosentino et al, ; Öğretmen et al, ; Schildgen et al, ) are inconsistent with the aforementioned research.…”

“…Bakırcı, Yoshizawa, & Özer, ; Abgarmi et al, ), where a thick crust and mantle lithosphere exist (e.g. Delph et al, ; Portner et al, ). Also, the concomitance of uplift in the modern Central Taurides and subsidence in the offshore Outer Cilicia Basin (OCB) to the south (e.g.…”

Thermal history of the western Central Taurides fold-thrust belt: Implications for Cenozoic vertical motions of southern Central Anatolia

“…The stratigraphy of the Mut Basin is undeformed (e.g., Fernández-Blanco et al, 2019), leading to the interpretation that km-scale uplift was driven by deep processes related to the underlying Cyprus subduction zone (e.g., Schildgen et al, 2012;Schildgen et al, 2014). The region is therefore considered a potential location in which we may study the interplay between subduction dynamics and rapid surface uplift and subsidence (e.g., Schildgen et al, 2014;Delph et al, 2017;Meijers et al, 2018). The specific causes of uplift in the southern Central Taurides, and whether the uplift history represents regional-scale rise of the Central Anatolian Plateau, remain uncertain.…”