A NEW PERSPECTIVE ON ANATOLIAN KINEMATICS

Anatolia is the global archetype of continental escape, as GPS motions of the wedge-shaped plate differ regionally from northeastwards to southwestwards (from east to west). In traditional interpretations Anatolia was extruded westward from the Arabian-Eurasian collision, rotating counterclockwise (CCW) into the oceanic free-faces of the Mediterranean and Aegean, with a dramatical extension in western Anatolia. We analyzed the recent GPS velocity datasets, and decomposed them into N–S and E–W components, revealing that westward motion is dramatically constant across the whole plate, while southward components increased dramatically in western Anatolia. The velocity components are related to different tectonic mechanisms. Arabian Plate collided with Eurasia and drives the Anatolian plate to move uniformly westwards. Meanwhile, western Anatolia was progressively more affected by the southward retreating African subducting slab, which significantly increased the southward components of the velocity field and caused the change of the modern velocity field we observe from east to west. Based on our analysis, we suggest the Anatolian plate is moving as one plate westwards with an extra extension in its west caused by the local driving mechanism, slab rollback, rather than separated microplates. The collision-related extrusion is the main driving mechanism of Tectonic escape. This new perspective of interpreting geodetic data also has the potential to be further applied to other zones of collision and escape tectonics, including SE Asia where blocks escaping the India-Asia collision are variably affected by retreating slabs from the Pacific and Indian oceans.