INTRODUCTION Recent Ocean Drilling Program results (ODP Leg 160; Emeis et al., 1996) have stimulated renewed interest in the tectonic evolution of the east- ern Mediterranean region. Within a large area of southwestern Turkey (Fig. 1), a regionally extensive Late Cretaceous ophiolite is underlain by tec- tonic melange, highly dismembered thrust sheets, and more coherent thrust sheets, which have a maximum age range of Late Permian to early Tertiary (De Graciansky, l972; Poisson, 1977; S ¸ enel et al., 1989; Okay, 1989). In this study we focus on the melange unit, previously interpreted as coherent thrust sheets related to continental collision. We reinterpret this as an em- placed subduction-accretion complex with off-scraped seamounts and dis- cuss the resulting tectonic implications (Collins and Robertson, 1995). REGIONAL TECTONOSTRATIGRAPHY Five major tectonostratigraphic units are present (Fig. 1); ascending in tectonostratigraphic order these are: (1) the Menderes metamorphic com- plex and Bey Daˇ gları platform, which represent an extensive autochthonous unit; (2) the Lycian thrust sheets, which are upper Paleozoic to Tertiary, dominantly carbonate thrust sheets capped by bedded radiolarites, shales, and volcaniclastic sedimentary rocks and include Eocene-Oligocene clastic rocks (Yavus Unit); (3) the Lycian melange, consisting of thick (<2 km) cha- otic lithologies—this is the main focus of this paper; (4) the Lycian ophio- lite, which is mainly serpentinized peridotite, and sole; and (5) Paleogene transgressive marine limestones that unconformably overlie the Lycian melange. The first four structural units are separated by major thrusts, the fourth and fifth by a regionally significant unconformity (Fig. 2). NATURE OF THE LYCIAN MELANGE Two intergradational subunits are recognized on the basis of field obser- vations in the frontal regions of the Lycian allochthon (Fig. 3): (1) the lay- ered tectonic melange and (2) the ophiolitic melange. Type localities are Göçgediˇ gi Tepe for the layered tectonic melange (Fig. 4) and Kes ¸ if Da ˇ gı for the ophiolitic melange (Fig. 5). LAYERED TECTONIC MELANGE The Lycian thrust sheets are tectonically overlain by laterally incoherent sheets of siliceous marble, ranging from 1 to 10 m thick and <300 m long (Figs. 2 and 3). The layered appearance of the limestones previously led to this unit being interpreted as a regularly bedded stratigraphic sequence Geology; March 1997; v. 25; no. 3; p. 255–258; 7 figures. 255 Lycian melange, southwestern Turkey: An emplaced Late Cretaceous accretionary complex Alan S. Collins Alastair H. F. Robertson Department of Geology and Geophysics, University of Edinburgh, Edinburgh EH9 3JW, United Kingdom ABSTRACT The Lycian thrust belt is an important part of the Tethyan orogenic belt in the eastern Mediterranean region. It includes a unit of internally disrupted, thin-skinned thrust sheets (lay- ered tectonic melange) and a melange rich in ophiolitic material (ophiolitic melange). The lay- ered tectonic melange is dominated by Mesozoic distal deep-water sedimentary rocks, and the ophiolitic melange includes disrupted thrust sheets of early Mesozoic shallow-water limestone and blocks of basalt of both mid-ocean ridge and within-plate geochemical affinities. A complete record of closure of a Tethyan oceanic basin began with Late Cretaceous intraoceanic subduc- tion, followed by latest Cretaceous trench-continental collision, and ended with mid-Tertiary continental collision, and orogenic collapse. Figure 1.Tectonic map of southwest Turkey, highlighting relevant tec- tonostratigraphic units. Figure 2. Rock-relations diagram for Lycian region, showing idealized interrelationships between tectonostratigraphic units and timing of thrusting; (a) initially Maastrichtian, with Paleogene reactivation; (b) late Eocene; (c) early Oligocene; (d) middle Miocene.