Subduction dynamics beneath Anatolia: tectonic, metamorphic and thermal consequences on the Aegean/Anatolian transition zone

Slab rollback and tearing are common features in subduction zones and have a strong impact on the tectonic and metamorphic evolution of the overriding plate. Slab tearing below the Aegean Sea for instance had first order tectonic and magmatic consequences because it induced toroidal asthenospheric mantle flow that controls the typology and distribution of melts at the surface but also lateral gradients of extension in the upper plate. However, coupling mechanisms between the complex 3D mantle flow at depth and deformation in the upper plate above slab tear have received little attention so far. In addition, there is no consensus about the time-space evolution and the thermal consequences of such tearing. This study is focused on the description of the distribution and kinematics of deformation in the eastern part of the Aegean Sea, within the gradient of extension between the Cyclades and the Menderes Massif, where the Dodecanese and Eastern Aegean Islands archipelagos have been little studied. We complete the description of the extensional strain field above the slab tear and discuss the geodynamic implications of the observed kinematics and P-T evolution. We firstly clarify the correlations and differences between the Aegean Sea and the Menderes Massif in terms of lithological and tectonic units and in terms of metamorphic evolution. Secondly, we further show that in the transition zone between Aegea and the Menderes, extension related to slab retreat and tearing keeps a constant NNE-SSW direction accommodating the difference in finite rates of extension, and no localized large strike-slip fault and blocks rotation. We thus suggest that a SSW-striking simple ductile flow in the now-exhumed lower crust probably reflects the asthenospheric mantle flow above the tear. Through 3D numerical models involving slab rollback and tearing, we highlight that subduction-related asthenospheric return flow controls the overriding crustal deformation, favouring shear heating and thus heat production at the base of the crust. Results show that heat flow values are around 100 mW.m-2 and reach locally up to 130 mW.m-2 above the slab tear at 12.4 Myr at the base of the crust. We found that 46 % of heat flow is due to mantle shear heating, and the remaining part being due to the advection of hot material. These thermo-mechanical instabilities primarily trigger and control the distribution of crustal-scale thermal domes, analogous to crustal and lithospheric boudinage in the back-arc domain. These instabilities may thus explain (1) the HT parageneses in MCCs and (2) the development of the ductile lower crustal flow observed in the transitional zone between the Aegean Sea and the Menderes Massif.


Tectonic history of basins sited along the western section of the North Anatolian Fault System, Turkey
SARP, Gülcan; Gurboga, Sule; Toprak, Vedat; Duzgun, Sebnem (2014-01-01)
Geological and geomorphological features of basins along the western half of the North Anatolian Fault System (NAFS) are used to constrain the formation of these basins by localization of deformation and the total displacement, and to determine the timing of basin development. In this study, tectonic influence direction of the NAFS on tectonic and hydrologic basins Bolu, Yenicaga, Dortdivan, Cerkes, Ilgaz and Tosya has been investigated to deduce information about the formation stages and interaction betwee...
Tectonics and Magmatism in Turkey and the Surrounding Area
Bozkurt, Erdin; Piper, John D A (Geological Society of London, 2020-01-01)
The volume is divided into five sections: Tethyan evolution, Neotethyan ophiolites, post-Tethyan basin evolution, neotectonics and igneous activity. The first two sections deal with Tethyan oceans, whose growth and subsequent closure dominated the geodynamic framework in the Mesozoic and Cenozoic. The subsequent sections deal with more recent geological developments from the Balkan Peninsula in the west to the Transcaucasus in the east that followed consumption of the Tethyan oceans. There is a broad mix of...
Crustal deformation and crust mantle interaction in active collision zones Cental Tibet and East Anatolia
Zandt, George; Özacar, Atilla Arda; Beck, Susan L. (2004-12-13)
A major question in the tectonics of collisional mountain belts concerns the relative coupling or decoupling of the crust and mantle. In this respect, recent IRIS PASSCAL seismic experiments in the Tibetan and East Anatolian plateaus provide an important opportunity to study crustal deformation and crust-mantle interactions in continental collisions. Receiver functions (RF) from the dense INDEPTH III seismic array that was deployed across central Tibet, show a crustal thickness of $\sim65$ km and a very wea...
Sedimentary basin deformation: an incremental stress approach
Tuncay, Kağan; Ortoleva, P. (Elsevier BV, 2000-8)
A key component of sedimentary basin evolution is the spatial distribution and temporal variation of stress and deformation. The many deformation processes (poroelasticity, fracturing, irreversible nonlinear viscosity, and pressure solution) are inextricably bound in a tightly coupled network which, in turn, is coupled to a myriad of basin diagenetic, thermal and hydrologic processes. In the approach presented here, the various deformation processes are integrated through an incremental stress approach. Tog...
AKIMAN, O; ERLER, A; GONCUOGLU, MC; Güleç, Nilgün Türkan; GEVEN, A; TURELI, TK; KADIOGLU, YK (1993-12-01)
The closely related assemblage of igneous and metamorphic rocks that lie within a triangular area approximately bounded by the Tuzgolu Fault, the Ecemis Fault and the Izmir-Ankara-Erzincan Suture and between the lines connecting Ankara, Sivas and Nigde is called the Central Anatolian Crystalline Complex (CACC). The granitoids cropping out within the CACC can be divided areally into three groups: (1) a large number of individual small plutons which form an arcuate set and curve from NE-SW to NW-SE and extend...
Citation Formats
E. Bozkurt, “Subduction dynamics beneath Anatolia: tectonic, metamorphic and thermal consequences on the Aegean/Anatolian transition zone,” presented at the EGU General Assembly 2018, Vienna, Austria, 2018, Accessed: 00, 2021. [Online]. Available: