The Cubukludag graben, south of Izmir: its tectonic significance in the Neogene geological evolution of the western Anatolia

Field studies on the Neogene successions in south of izmir reveal that subs equent Neogene continental basins were developed in the region. Initially a vast lake basin was formed during the Early-Middle Miocene period. The lac ustrine sediments underwent an approximately NS shortening deformation to t he end of Middle Miocene. A small portion of the basin fill was later trapp ed within the N-S-trending, fault-bounded graben basin, the Cubukludag grab en, opened during the Late Miocene. Oblique-slip normal faults with minor s inistral displacement are formed possibly under N-S extensional regime, and controlled the sediment deposition. Following this the region suffered a p hase of denudation which produced a regionwide erosional surface suggesting that the extension interrupted to the end of Late Miocene-Early Pliocene p eriod. After this event the E-W-trending major grabens and horsts of wester n Anatolia began to form. The graben bounding faults cut across the Upper M iocene-Pliocene lacustrine sediments and fragmented the erosional surface. The Cubukludag graben began to work as a cross graben between the E-W grabe ns, since that period. (C) 2001 Editions scientifiques et medicales Elsevie r SAS.