Evidence for similar to 80-75 Ma subduction jump during Anatolide-Tauride-Armenian block accretion and similar to 48 Ma Arabia-Eurasia collision in Lesser Caucasus-East Anatolia

2012-05-01
Rolland, Yann
PERİNÇEK, DOĞAN
Kaymakcı, Nuretdin
Sosson, Marc
Barrier, Eric
Avagyan, Ara
Orogens formed by a combination of subduction and accretion are featured by a short-lived collisional history. They preserve crustal geometries acquired prior to the collisional event. These geometries comprise obducted oceanic crust sequences that may propagate somewhat far away from the suture zone, preserved accretionary prism and subduction channel at the interplate boundary. The cessation of deformation is ascribed to rapid jump of the subduction zone at the passive margin rim of the opposite side of the accreted block. Geological investigation and Ar-40/Ar-39 dating on the main tectonic boundaries of the Anatolide-Tauride-Armenian (ATA) block in Eastern Turkey, Armenia and Georgia provide temporal constraints of subduction and accretion on both sides of this small continental block, and final collisional history of Eurasian and Arabian plates. On the northern side, Ar-40/Ar-39 ages give insights for the subduction and collage from the Middle to Upper Cretaceous (95-80 Ma). To the south, younger magmatic and metamorphic ages exhibit subduction of Neotethys and accretion of the Bitlis-Puturge block during the Upper Cretaceous (74-71 Ma). These data are interpreted as a subduction jump from the northern to the southern boundary of the ATA continental block at 80-75 Ma. Similar back-arc type geochemistry of obducted ophiolites in the two subduction-accretion domains point to a similar intra-oceanic evolution prior to accretion, featured by slab steepening and roll-back as for the current Mediterranean domain. Final closure of Neotethys and initiation of collision with Arabian Plate occurred in the Middle-Upper Eocene as featured by the development of a Himalayan-type thrust sheet exhuming amphibolite facies rocks in its hanging-wall at c. 48 Ma.
Citation Formats
Y. Rolland, D. PERİNÇEK, N. Kaymakcı, M. Sosson, E. Barrier, and A. Avagyan, “Evidence for similar to 80-75 Ma subduction jump during Anatolide-Tauride-Armenian block accretion and similar to 48 Ma Arabia-Eurasia collision in Lesser Caucasus-East Anatolia,” pp. 76–85, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/44962.