Stratigraphical evidence for the depression of the northern margin of the Menderes-Tauride Block (Turkey) during the Late Cretaceous

摘要

Upper Cretaceous units on the Menderes-Tauride Block show a transition from a passive continental margin to a pelagic basin. This transition is related to the emplacement of ophiolitic nappes. The pelagic sediments were studied in the Aydmcik and Arslankoy (Mersin) areas in the central Tauride region, and in the Munzur Mountains in eastern Tauride region. In the Aydmcik area Upper Cretaceous units consist of Upper Campanian carbonate breccias with rudist fragments; Upper Campanian-Lower Maastrichtian slope-to-basinal sediments overlie these carbonate breccias disconformably. In the Arslankoy area the Upper Campanian-Maastrichtian Yavca Formation consists of Globotruncana-bearing biomicrites, siliciclastic turbidites, calciturbidites and debris flows and overlies Jurassic-Cretaceous platform carbonates disconformably. The uppermost levels of the Liassic-Cenomanian platform carbonates in the Munzur Mountains are composed of Cenomanian Hippurites/Orbitolina-bearing reefal limestones and then Turonian-Campanian Globotruncanidae-bearing biomicrites. The stratigraphic sequence in the Menderes-Tauride Block shows that rifting to form a northern Neotethyan basin took place in the Triassic and gave rise to the Inner Tauride Ocean. From Jurassic to Cenomanian times, the northern part of the Menderes-Tauride Platform formed a passive continental margin. In the Late Cretaceous the Inner Tauride Ocean is believed to have commenced intra-oceanic, northward subduction. Inner Tauride oceanic crust-derived nappes were emplaced southward onto the Menderes-Tauride Block. Flexural foreland basins in which pelagic sediments were deposited were formed in the Taurus Mountains related to southward thrusting and the emplacement of the ophiolite nappes.