Uplift, deformation and fluid involvement within an active normal fault zone in the Gulf of Corinth, Greece

Abstract

The active Pisia Fault Zone is exposed close to the crest of a rotated carbonate fault-block that forms part of the southern margin to the Gulf of Corinth half-graben in central Greece. The crest of the fault-block lies above sea-level whilst in the hanging-wall a marine basin exists. As a result, the diagenetic and structural characteristics of the fault zone record complex fluid involvement. Both early phreatic carbonate syn-kinematic cements (characterized by drusy fabrics, baroque dolomites and crack-seal textures) and late vadose carbonate syn-kinematic cements (characterized by flowstones containing cave-collapse debris) exist in the uplifted footwall to the fault. Downward percolation of vadose meteoric waters and the upwelling of pore waters with elevated temperatures produced the diagenetic features observed within the fault zone. The co-existence of early phreatic and late vadose cements within the fault zone is related to footwall uplift across the water-table and subsequent erosional unroofing. The present-day elevation of phreatic cements to c . 650m above current sea-level, provides a minimum estimate of footwall uplift along the fault. The wider implication is that temporal changes in deformation and fluid flow may typify fault-block evolution.