Island arcs and the origin of folded ranges

Abstract

It is attempted to reconsider the problem of orogeny through a review of three arcuated systems: Tyrrhenian, Aegean, and Ceram. The Tyrrhenian Sea is inherited from a sheaf of Alpine ridges and furrows located between the Corso-Sardinian block to the west and the African-Adriatic platform to the south and east. The abyssal plain represents the tearing apart of these zones following the gradual curving of the Calabro-Lucanian arc. The Aegean Arc is part of the Hellenic-Tauric ranges. Its folding and thrusting is not due to the northward movement of a'Tethysian plate', but to an active, outward thrust over its foreland. The Aegean bulge results from the westward movement of Anatolia, being barred to the west by the eastward thrusting Calabro-Sicilian Arc. The frontal trenches rising towards the south to the so-called Mediterranean Ridge should be compared to the mollassic furrows that surround all arcuated folded ranges. The Banda Sea may correspond to a longitudinal extension similar to that of the Tyrrhenian Sea: it would be due to a compressional effect related to the north-westward movement of Australia. Transcurrent faults play an important role with two main directions, both being left-lateral: NNW or NW and E-W.