Brecciation and fracturing within neotectonic normal fault zones in the Aegean region

Abstract

Abstract Neotectonic normal fault zones cutting bedrock carbonates within the Aegean extensional province contain contrasting breccia types that record different stages of fault zone evolution at shallow (< 500 m) crustal levels. Initial blind faulting at depth produces a near-surface shatter zone. Locally, blocks within the shatter zone become increasingly disorganized as slip planes advancing through the zone, create incohesive breccia belts ahead of propagating tips. Mineralization and frictional wear accompanying fault movement form narrow compact breccia sheets adjacent to slip planes. In some major fault zones, fault movement is concentrated along metre-wide zones of intensely deformed stylobreccia. When slip planes reach the free surface, post-seismic stress release initiates a new fracture network that is superimposed on and restricted to breccia belts and sheets.