Impact of fault evolution in Gilbert-type fan deltas in the Evrostini area, south-central Gulf of Corinth, Greece

Abstract

Abstract In order to understand how syn-rift deposits are associated with border fault evolution, the outcrops around the Evrostini area in the southern Gulf of Corinth, Greece, are investigated. Two major border fault systems are identified in the study area, which are the Vela–Valimi–Xylokastro and Akrata–Xylokastro border fault complexes. The Vela–Valimi and Xylokastro faults were active in the Calabrian age when the WSW-trending linking faults were initiated at the Evrostini Mountain area and propagated eastwards. The Xylokastro Fault was reactivated in the Middle Pleistocene, when the Akrata Fault was created. It is proposed that WSW-trending faults were developed to link the Akrata and Xylokastro border faults. Longitudinal propagation of the rift margin in the area was segmented by three N–S striking transfer faults. These transfer faults are defined by N–S-aligned discontinuity of abrupt fault displacement termination, large horizontal steps of E–W-striking fault segments, and lateral offsets of syn-rift deposition with major changes in facies. The regional drainages were strongly influenced by border fault growth and along-strike segmentation. Near the tips of the border faults, the drainage may be forced to shift along with fault tip propagation. In contrast, in the boundaries of rift segmentation, the drainage maintains its course and proceeded parallel to the orientation of N–S striking transfer faults. Drainage patterns and their configurations with border fault systems from the field study provide an analog model to predict the sub-surface syn-rift deposits in buried rift basins, such as the North Sea.