Along strike changes in the structural evolution over a brittle detachment fault:: Example of the Pleistocene Corinth-Patras rift (Greece)

The Patras, Corinth, and northern Saronic gulfs occupy a 200-km-long, N120 degrees trending Pleistocene rift zone, where Peloponnese drifts away from mainland Greece. The axes of Patras and Corinth basins are 25 kin apart and linked by two transfer-fault zones trending N040 degrees. The older one defines the western slope of Panachaikon mountain, and the younger one limits the narrow Rion-Patras littoral plain. Between these two faults, the ca. 4-km-thick Rion-Patras series dips 20-30 degrees SSW. It is part of the Patras gulf syntift deposits, which pile in an asymmetric basin governed by a fault dipping ca. 25-35 degrees NNE, located in the southern Gulf of Patras. Mapping of this fault to the east in northern Peloponnese shows that it is an inactive north-dipping low-angle normal fault (0 degrees to 30 degrees N), called the northern Peloponnese major fault (NPMF). The structural evolution of the NPMF was different in the gulfs of Patras and Corinth. In the Gulf of Patras, it is still active. In northern Peloponnese, footwall uplift and coeval southward tilting flattened the fault and locked its southern part. Steeper normal faults formed north of the locked area, connecting the still active northern part of the NPMF to the surface. After several locks, the presently active normal faults (Psathopyrgos, Aigion, Helike) trend along the southern shore of the Gulf of Corinth. This migration of faults caused the relative 25 kin northward shift of the Corinth basin, and the formation of NE-SW trending transfer-faults between the Corinth and Patras gulfs. (c) 2005 Elsevier B.V. All rights reserved.