BIOCHRONOLOGY OF JURASSIC AND EARLY CRETACEOUS RADIOLARITES FROM THE LYCIAN MÉLANGE (SW TURKEY) AND IMPLICATIONS FOR THE EVOLUTION OF THE NORTHERN NEOTETHYAN OCEAN

Abstract

New radiolarian ages for blocks radiolarian cherts associated with other blocks of distal pelagic facies and ophiolitic lithologies within the Lycian Mélange, SW Turkey, indicate deposition during Mid-Jurassic to Early Cretaceous time. Radiolarites overlying pink pelagic limestones of an allochthonous carbonate unit accumulated during the Mid- to Late Jurassic. On the basis of structural evidence the Lycian Mélange is inferred to have been rooted within the Northern Neotethys, to the north of the Tauride-Anatolide microcontinent. The Lycian radiolarites can be compared with other dated radiolarites from the Izmir-Ankara suture, the root zone of the Northern Neotethyan ocean. Based on all the available radiolarian data it is inferred that radiolarites accumulated within the Northern Neotethys in western Turkey from Late Triassic (Mid-Carnian to Late Norian) to Mid-Cretaceous (Cenomanian) time. The radiolarites were later detached from their inferred oceanic basement and accreted within a subduction complex during the Late Cretaceous (Turonian-Maastrichtian) and emplaced over the northern margin of the Tauride-Anatolide continent together with slices of continental margin and ophiolitic lithologies. © The Geological Society of London 2006.