Breaking plates: Creation of the East Anatolian fault, the Anatolian plate, and a tectonic escape system

Lateral movement of lithospheric fragments along strike-slip faults in response to colli-sion (escape tectonics) has characterized convergent settings since the onset of plate tectonics and is a mechanism for the formation of new plates. The Anatolian plate was created by sequential connection of strike-slip faults following >= 10 m.y. of distributed deformation ultimately localized into plate-bounding faults. Thermochronology data and seismic images of lithosphere structure near the East Anatolian fault zone (EAFZ) provide insights into development of the new plate and escape system. Low-temperature thermochronology of rocks in and near the EAFZ are significantly younger than in other fault zones in the gion, e.g., apatite (U-Th)/He: 11-1 Ma versus 27-13 Ma. Young apatite (U-Th)/He ages thermal history modeling record thermal resetting along the EAFZ over the past '5 m.y. are interpreted to indicate thermal activity triggered by strike-slip faulting in the EAFZ it formed as a through-going, lithosphere-scale structure. The mechanism for EAFZ forma-tion may be discerned from S-wave velocity images from the Continental Dynamics-Cen-tral Anatolian Tectonics (CD-CAT) seismic experiment. These images indicate that thin strong Arabian lithospheric mantle extends '50-150 km north beneath Anatolian crust would have been located near the present surficial location of the Bitlis-Zagros suture zone (co-located with the EAFZ in our study area) at ca. 5 Ma. Underthrusting of strong Arabian lithosphere facilitated localization of the EAFZ and thus was a fundamental control on formation of the Anatolian plate and escape system.

Automated summary

Escape tectonics is a mechanism for the formation of new plates, in which lithospheric fragments move laterally along strike-slip faults in response to collision. Analysis of thermochronology data and seismic images near the East Anatolian fault zone provides insights into the development of the Anatolian plate and escape system. The younger ages of rocks in and near the EAFZ, as well as the presence of strong Arabian lithospheric mantle beneath the Anatolian crust, suggest that thermal activity and underthrusting of Arabian lithosphere played a fundamental role in the formation of the Anatolian plate and escape system.