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Continent-continent collision drives crustal deformation, topographic rise and geodynamic change. Africa-Eurasia convergence accommodated in the Eastern Mediterranean involved subduction of the Neotethyan oceanic lithosphere in Anatolia. Subduction was followed by collision of continental crust of Greater Adria with Eurasia to form the Izmir-Ankara-Erzincan suture zone. Discerning the effects of this collision from pre-collisional ophiolite obduction-related orogeny of Greater Adria is notoriously difficult. Estimates on the timing of collision in Central Anatolia are based on a forearc-to-foreland basin transition along the Eurasian margin and suggest a ~60 Ma age of initial collision. Here, we assess whether this age is also representative for collision in Eastern Anatolia and across the Cenozoic Sivas Basin that straddles the Greater Adria-Europe suture. To this end we retro-deform regional block rotations in the Pontides, the Kırşehir Block and the Taurides, building a first-order regional 'block circuit' around the Sivas Basin. We show that up to ~700 km of convergence must have been accommodated across the Sivas Basin after Central Anatolian Kırşehir-Pontide collision at ~60 Ma – an order of magnitude more than estimated crustal shortening, and that wholesale lithospheric subduction must have occurred throughout much of the Cenozoic. Paleocene collision would require that this subduction consumed continental lithosphere, which is unlikely. We consequently infer that oceanic subduction continued much longer in Eastern Anatolia, perhaps well into the Miocene. We postulate that prolonged oceanic subduction and slab pull drew the Eastern Taurides north relative to the Central Taurides, leading to shortening and oroclinal bending in Central Anatolia. The diachronous demise of the Neotethys Ocean in Anatolia, as a function of its paleogeography, is thus a likely driver for the strong non-cylindricity of the Cenozoic Anatolian collisional orogen. • Continent-continent collision in Anatolia was diachronous. • After ~60 Ma, ~700 km of convergence was yet to be accommodated in Eastern Anatolia. • Convergence accommodated is an order of magnitude more than crustal shortening. • Prolonged subduction resulted from a kinked passive margin paleogeography. • Oceanic subduction in Eastern Anatolia continued longer than previously thought. [ABSTRACT FROM AUTHOR]

Abstract: The Zagros Mountains are the result of the Arabia/Eurasia collision initiated at ~35Ma as the rifted Arabian lithosphere was underthrusted beneath the Iranian plate due to its negative buoyancy. The onset of crustal thickening started at ~25Ma, as recorded by the hinterland exhumation and foreland clastic deposition. Deformation throughout the Arabia/Eurasia collision zone and the uplift of the Iranian plateau occurred after 15–12Ma, as a result of shortening/thickening of the thin Iranian crust. We emphasize that only 42% of the post-35Ma convergence is partitioned by shortening within central Iran. Tomographic constraints show ongoing slab steepening or breakoff in the NW Zagros, whereas underthrusting of the Arabian plate is observed beneath central Zagros. The current subduction dynamics can be explained by the original lateral difference in the buoyancy of the distal margin that promoted slab sinking in NW Zagros and underthrusting in central Zagros. Critical wedge approach applied to the Zagros favors the hypothesis of strong brittle crust detached above a viscous lower crust. In contrast, the weak sedimentary cover deforms by buckling of a thick multilayered cover. Thrust faulting associated with folding occurs in the competent layers and is responsible for most of the earthquakes. There is evidence that the role of the slab pull force in driving the Arabian plate motion was reduced after ~12Ma. Large-scale mantle flow induced by mantle upwelling at the Afar plume appears to be the main driver of the Arabia plate motion. We stress that the main kinematic change in the Zagros region occurred at 15–12Ma as the Zagros uplifted, before the Arabian slab detached. The Zagros appears key to investigate coupling between continental rheology, plate driving forces and mountain building, in which the role of rift inheritance appears to be central. [Copyright &y& Elsevier]

Abstract: In the southern Uralides, Permian magmatism, tectonism and metamorphism concentrate in the East Uralian Zone, such that this zone provides the key for understanding of the late phase of the Uralian orogeny. Carboniferous distal marine sediments and lenses of amphibolite–serpentinite associations show that the lithospheric precursor of the East Uralian Zone was largely oceanic. In the Latest Carboniferous, the Kazakhstanides collided with the Uralides, but relics of the oceanic basin between both units were conserved and accommodated a large part of Permian deformation. Structural data provide evidence that a NW-directed plate convergence was partitioned in W-directed compression and N-directed strike-slip. Additionally, they show that granitic melts, which had formed in the thickened crust of the Uralides, migrated eastward into the strike-slip belt of the East Uralian Zone. Also the exhumation of the plutonic rocks occurred eastward, oblique to the direction of regional extension, indicating that upper crust and lower crust deformed mainly decoupled from one another. We suggest that the emplacement of the granite–gneiss complexes contributed significantly to the consolidation of the orogenic crust in the eastern Urals. [Copyright &y& Elsevier]

The geodynamics and plate tectonics of the South China Sea (SCS)-Taiwan region since Miocene times are uncertain because the former extent and tectonic configuration of the subducted easternmost SCS along the Manila trench is uncertain. Here we unravel the regional kinematic context from main offshore constraints including published unfolding of the Manila slab from seismic tomography, which provides insight on restoring the subducted part of the SCS. We reconstruct a bayonet-shaped, stepped northern SCS continent-ocean boundary (COB) that consists of a northeastern SCS COB segment we call 'S3', trending N070° that roughly parallels the present SCS shelf; a 350-km long ~N-S trending segment S2 that steps north to Hualien; and, a third segment S1 that extends from east of Hualien beneath the Ryukyu subduction zone trending N085° that ends near Miyako Island in the Ryukyus. The distance between present COB and S1 gives extension through time in the Okinawa trough, with a maximum of ~100 ± 20 km extension since late Miocene (10 Ma). We interpret S1 as a zone of weakness since ~18 Ma that ruptured from Miyako Island to east of Hualien as a tear fault, with the Huatung basin-Philippine Sea plate (HB-PSP) subducting northwestward between the two sides of the tear fault. The Manila transcurrent fault initiated ~18 Ma ago at the onset of the tear and progressively moved eastward, creating the intra-oceanic Luzon arc, which began collision ~7 Ma ago along the EU margin. From ~7 to 6.5 Ma Taiwan was uplifted west of the Longitudinal valley. The Luzon arc and forearc basins were shortened within the Coastal range. Plate kinematic reconstructions from ~18 Ma to Present are synthesized in terms of continental or oceanic nature of the main PSP-HB and EU entities before their subduction that provide new understanding on Taiwan, PSP-SCS kinematics, and regional histories. • 350-km N-S bayonet-shaped Eurasia (EU) continent-ocean boundary (COB) west of Taiwan. • EU COBs before and after Okinawa trough opening constrain South China Sea subduction. • Clockwise Luzon arc rotated blocks collide EU margin before incorporation in Coastal range. • Kinematic reconstructions synthesize main stages of South China Sea subduction and Taiwan uplif. [ABSTRACT FROM AUTHOR]