Complex interactions fault fans developed in a strike-slip system: Kozan Fault Zone, Eastern Mediterranean Sea

Abstract

Interpretation of high-resolution multichannel seismic reflection profiles shows that the Kozan Fault Zone is characterized by northeast–southwest-striking and mainly southeast-dipping planar faults which show significant normal-sense dip separations. Traced toward the southeast these faults progressively swing to assume an east–west trend along the northern margin of the Outer Cilicia Basin. The Kozan Fault Zone initially occupied a wide zone of distributed strike-slip translation in the Early Pliocene, but was subsequently concentrated into a narrowly focused strike-slip fault zone in the Late Pliocene and Quaternary. During the Late Pliocene, the Kozan Fault Zone propagated toward the southwest creating a restraining bend in the Cilicia Basin, and a new east–west oriented strike-slip fault (i.e., Silifke–Anamur Fault) in the Outer Cilicia Basin. Two additional fault fans with small normal-sense dip separations occur across the Kozan Fault zone, exhibiting spectacular examples of fault interferences and growth strata architectures. The east–west striking and south-dipping fault fan developed in the Early Pliocene, whereas the northwest–southeast striking and largely northeast dipping fault fan developed in the Late Pliocene. Each fan is composed of numerous listric faults which sole on bedding-parallel detachment surfaces at various levels within the Pliocene–Quaternary succession. These faults developed as the result of gravitational sliding of thick delta and prodelta successions supplied into the Cilicia Basin by the Göksu River. The change in the kinematic regime in the Kozan Fault Zone is reflected in the dynamics of the gravitationally collapsing mass, and the northwest–southeast striking and largely northeast dipping fault developed. A small angle between the strikes of these two fault fans prevented the lock-up of the east–west striking and south-dipping faults, so both faults set to remain active throughout the Late Pliocene–Quaternary.