STRUCTURES AND KINEMATICS IN THE NORTHEASTERN MEDITERRANEAN - A STUDYOF AN IRREGULAR PLATE BOUNDARY

Extensional structures are prominent in the northeastern Mediterranean , a unique sector of the Africa-Eurasia plate convergence zone. To exp lain this paradoxical situation, we analyse here the young tectonics o f this region by examining its structural elements and plate kinematic s. Offshore multichannel seismic reflection profiles and onland geolog y show that the stuctural settings are different on the two sides of t he northeastern Mediterranean triple junction (AFR-ARB-ANA). On the ea st, stuctures controlled by strike-slip and by compression coexist, wh ereas on the west compression is not very conspicuous. Here, deep basi ns separated by a partly submerged ridge are prominent. We interpret t he ridge, which comprises the Kyrenia- Misis-Andirin Unit at its core, as a large flower structure which extends from southeastern Turkey to Cyprus; the Adana-Cilicia and the Iskenderun-Latakia-Mesaoria Basins on its flanks are interpreted as due to extension. This interpretation agrees with the relative motions between the Africa, Arabia, Eurasia and Anatolia plates in this region. Analysis of the local plate kinema tics reveals that strike-slip predominates along the southern boundary of the Anatolia plate in this region, as a result of Anatolia's westw ard escape. East of the triple junction this motion is associated with comparable shortening transverse to the plate boundary, whereas west of the triple junction the motion transverse to the plate boundary var ies between slight compression to extension, depending mainly on the l ocal strike of the plate boundaries. These variations, calculated from regional data, correlate well with the observed structural changes al ong the northeastern Mediterranean sector of the plate convergence zon e. The structural-kinematic analysis explains both the lateral changes in the deformation style and the existence of local extension in the northeastern Mediterranean.