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

Abstract

The modern physiography of central Turkey is dominated by the 1-km-high Central Anatolian Plateau and the Central Tauride mountains that form the southern plateau margin. These correspond to a Cretaceous-Eocene backarc extensional province and forearc fold-thrust belt, respectively. The extent to which the morphology of the Miocene plateau was inherited from the physiography of the Cretaceous-Eocene subduction zone that assembled the Anatolian crust has not been tested but is important if we are to isolate the signal of Miocene and younger subduction dynamics in the formation of the modern plateau margin. There is no known stratigraphic record of the post-Eocene pre-Miocene evolution of the Taurides. We therefore collected rock samples across the Taurides and used zircon (U-Th)/He (ZHe), apatite (U-Th)/He (AHe), and apatite fission-track (AFT) low-temperature thermochronometers to constrain cooling; we interpret these thermochronometers to signal erosional exhumation. We use inverse thermal modeling to aid interpretation of our results and find that: (1) thermochronometers across the Taurides were reset as a result of heating by the emplacement of the Antalya and Bozkır nappes; (2) AFT and ZHe Eocene cooling ages are related to structurally driven uplift and erosional exhumation on major thrust culminations; (3) dispersed AHe ages record low rates of Oligocene-early Miocene cooling and hence low rates of erosional exhumation; and (4) fast rates of cooling were determined for samples along the margin of the Köprüçay Basin. We interpret that early Miocene cooling is a signal of active erosion of the western Central Taurides at a time of marine sedimentation in the Mut Basin on the southern Central Taurides, and these differing histories may reflect evolution above the Antalya and Cyprus slabs. Our thermochronological data, the enigmatic development of the Antalya Basin, and thrusting within the basin may be explained as the surface expression of stepwise delamination of the Antalya slab from the Tauride hinterland to its current position below the Gulf of Antalya since early Miocene time over a distance of ~150 km. GEOSPHERE GEOSPHERE, v. 15, no. 6

Towards interactive global paleogeographic maps, new reconstructions at 60, 40 and 20 Ma

“…Our paleogeographic reconstructions of these regions are simplified from Barrier et al (2018) and Popov et al (2004), and follow the tectonic models of McQuarrie and Van Hinsbergen (2013) and Van Hinsbergen et al (Van Hinsbergen et al, 2020;. Our paleogeographic reconstructions in this region are mainly restricted to the location of paleoshorelines and do not consider Late Miocene-Pleistocene uplift (Cosentino et al, 2012;Fernández-Blanco et al, 2019;Öğretmen et al, 2018) which have been proposed to be a responses to lithospheric delamination (Bartol and Govers, 2014;Göğüş et al, 2017), slab breakoff (Portner et al, 2018;Schildgen et al, 2018),and to the arrival of the subducting African margin to the southern Taurides (McPhee et al, 2019).…”

Lithospheric unzipping explaining hot orogenesis during continental subduction

“…This process of decoupling may utilize the same rheological contrast that permits delamination by peeling mantle lithosphere from a plate (Göğüş & Pysklywec, 2008;Memiş et al, 2020). Such peeling delamination is known to occur at within-plate settings (Göğüş & Ueda, 2018a), at former subduction zones where plate convergence has stopped, such as in the SW Carpathians and in the Antalya region (Göğüş et al, 2016;McPhee et al, 2019), and subducting slabs may trigger delamination of lithosphere at slab edges (Spakman & Hall, 2010;van de Lagemaat et al, 2021). With 'unzipping', we mean that delamination occurs in the downgoing plate lithosphere during its descent into a subduction zone, and the arrest of this process coincides with the final accretion of the crust to the upper plate.…”

“…This hypothesis has difficulty explaining why in Eocene and Oligocene time, shortly after accretion of the nappes, there was arc magmatism only tens of kms north of the Menderes massif. Moreover, the gradual peeling back of lithosphere is a process in which there is no plate boundary, and without net plate convergence (Göğüş & Ueda, 2018b;McPhee et al, 2019), whereas Africa-Europe convergence has been continuous. With the lithospheric unzipper hypothesis, subduction may have continued with a single, mantle-stationary or slowly retreating slab during accretion such that arc-trench distances remained stable, and the unzipped crust was underthrust far below the accretionary orogen in the upper plate (Figure 4).…”

Preparing the ground for plateau growth: Late Neogene Central Anatolian uplift in the context of orogenic and geodynamic evolution since the Cretaceous

“…Seismic stratigraphy across major faults, the development of flexural basins (e.g., Hall et al, 2005;Symeou et al, 2018), and structural and stratigraphic constraints on the onset of upper-plate contractional deformation in southern Cyprus (e.g., Kinnaird & Robertson, 2013) all suggest that the modern trench formed only in latest Miocene or Pliocene time. Furthermore, a long-lived subduction zone below Troodos is at odds with Late Cretaceous emplacement of the adjacent Hatay and Baer-Bassit ophiolites onto Arabia (McPhee & van Hinsbergen, 2018), which based on paleomagnetic and geochronological constraints, were part of the same microplate (e.g., Al-Riyami et al, 2002;Morris et al, 2006). Underthrusting of the African distal continental margin at the Cyprus Trench (Fig.…”