Evolution of the Lycian Allochthon, western Turkey, as a north-facing Late Palaeozoic to Mesozoic rift and passive continental margin

Abstract

Regional tectono-stratigraphic analysis allows widely distributed outcrops of mainly Mesozoic sedimentary rocks within the Lycian Allochthon, SW Turkey, to be correlated and placed within four regionally developed thrust sheets, the Karadağ Thrust Sheet (lowest), the Teke Dere Thrust Sheet, the Köyceğiz Thrust Sheet (highest), and the Yavuz Thrust Sheet. The Karadağ Thrust Sheet records Late Carboniferous, Lower and Upper Permian continental shelf/lagoonal deposition. The overlying Teke Dere Thrust Sheet includes a rift succession of Late Permian age that was subaerially exposed during much of the Triassic; a marine transgression followed in the Early Jurassic succeeded by subsidence that formed a continental slope from Middle Jurassic to Palaeocene times. The overlying Köyceğiz Thrust Sheet records Upper Triassic oceanic crust (along a rifted margin), overlain by a Lower Jurassic carbonate platform; this then subsided to form a continental slope that survived until Late Cretaceous times. The Lycian Allochthon is restored as a north-facing Mesozoic rift and passive margin taking account of structural evidence indicating southward thrust emplacement and comparisons of sedimentary successions. Mainly deep-water sediments of Triassic to Late Cretaceous age, preserved as blocks within mélange units above the Lycian Thrust Sheets (Layered Tectonic Mélange and Ophiolitic Mélange), are interpreted as deep-water sediments deposited on Mesozoic (Neotethyan) oceanic crust. Subduction of the ocean basin proceeded from north to south, beginning with accretion of oceanic-derived mélange and disrupted thrust sheets. Debris was shed into a continentward-migrating flexural foredeep, initially located along the distal edge of the continental margin in Campanian–Maastrichtian times; this foredeep then propagated southwards in stages over more proximal continental crust (including an intra-platform basin). The first main stage of southeastward propagation was in Palaeocene and Eocene times followed by a second stage in Oligocene–Miocene times. The Lycian Allochthon was finally emplaced over the most proximal (southeasterly) foredeep (i.e. the Kaş basin) in Late Miocene time. Copyright © 1999 John Wiley & Sons, Ltd.