Tectonic and sedimentological evolution of the Pliocene–Quaternary basins of Zakynthos island, Greece: case study of the transition from compressional to extensional tectonics

Abstract

Pliocene–Quaternary basins of the Ionian islands evolved in a complex tectonic setting that evolved from a mid to late Cenozoic compressional zone of the northern external Hellenides to the rapidly extending Pliocene–Quaternary basins of the Peloponnese. The northern limit of the Hellenic Trench marks the junction of these two tectonic regimes. A foreland‐propagating fold and thrust system in the northern external Hellenides segmented the former Miocene continental margin basin in Zakynthos and permitted diapiric intrusion of Triassic gypsum along thrust ramps. Further inboard, coeval extensional basins developed, with increasing rates of subsidence from the Pliocene to Quaternary, resulting in four principal types of sedimentation: (1) condensed shelf‐sedimentation on the flanks of rising anticlines; (2) coarse‐grained sedimentation in restricted basins adjacent to evaporitic diapirs rising along thrust ramps; (3) larger basins between fold zones were filled by extrabasinal, prodeltaic mud and sand from the proto‐Acheloos river; (4) margins of subsiding Quaternary basins were supplied at sea‐level highstands by distal deltaic muds and at lowstands by locally derived coarse clastic sediment.