Triassic evaporites and Plio-Quaternary diapirism in western Greece

Wide Triassic evaporite outcrops run parallel to the strike of Hellenide thrust faults in western Greece. They crop out along the leading edges of thrust sheets emplaced as part of the foreland-migrating fold-and-thrust belt. The evaporites acted as the plane of décollement for thrust-sheet emplacement over much of the External Hellenides. Plio-Quaternary diapirs occur locally within the broad outcrops of Triassic evaporite. They are the result of local mobilization of evaporite after its emplacement. Their rise may have been initially triggered by Hellenide thrust-sheet loading and subsequently accentuated by Plio-Quaternary subsidence. Geophysical records and onland exposures show that diapiric rise controlled local sedimentation patterns above the sites of earlier Hellenide thrusts. The subsequent intrusion of diapirs into these cover sediments caused localized extensional structures to develop. This is best seen in SE Zakinthos, where strain-hardened, conjugate faults developed in friable Pliocene sandstones early in the intrusion history. Principal strains calculated from these sets demonstrate patterns of extension sub-orthogonal to intrusion margins. They are comparable with patterns known from other field and experimental examples, but contrast with some recent studies on diapir-related strains.