From back-arc extension to continental collision: A geophysical view of the Anatolian lithosphere

Abstract

This study investigates how large-scale tectonic blocks and inherited lithospheric boundaries across Türkiye can be resolved and characterized using integrated geophysical datasets. Despite numerous localized studies, a unified, crust-to-upper-mantle synthesis combining gravity, magnetic, seismicity, and P-wave velocity data has not yet been applied to understand the tectonic segmentation of the region. Three regional profiles (A–A', B–B′, and C–C′) were selected to traverse Western, Central, and Eastern Anatolia, capturing the geodynamic transition from extensional tectonics in the west to active continental collision in the east. The analysis integrates 3D gravity inversion, linear density contrast estimation, and P-wave tomography, supported by earthquake distribution statistics and magnetic anomaly interpretation. The results reveal distinct lithospheric domains: Western Anatolia is characterized by shallow Moho depths, low P-wave velocities, weak magnetic anomalies, and shallow seismicity, consistent with Miocene back-arc extension and core complex formation. Central Anatolia, particularly the Central Anatolian Crystalline Complex (CACC), exhibits elevated mid-crustal velocities and strong magnetic anomalies, indicating post-collisional magmatic stabilization. Eastern Anatolia shows pronounced gravity lows, broad low-velocity anomalies, and deeper seismicity beneath the East Anatolian Plateau, consistent with ongoing crustal thickening and lithospheric delamination. Integrated interpretations highlight the influence of inherited sutures and later tectonothermal overprinting on present-day geophysical patterns. A three-stage tectonic model is proposed—comprising late Mesozoic to Paleogene collision and suturing, Miocene back-arc extension, and Neogene to present-day collision and dynamic uplift. The study also introduces two new geodynamic perspectives: the reactivation and stabilization of Central Anatolia as a microplate core, and the classification of the East Anatolian Plateau as an actively evolving, post-collisional dynamic crustal system. These findings offer a new tectonic framework for Türkiye and contribute broadly to understanding lithospheric processes in continental collision zones.