XI.—Serpentine Lavas, the Ankara Mélange and the Anatolian Thrust

Abstract

SynopsisEvidence is given that many of the Mesozoic, geosynclinal serpentines of Turkey are deep-sea lavas, and that they functioned as efficient fertilizers of surface waters leading to rich crops of radiolaria now preserved in cherts and limestones. Furthermore, in anticlinals at Ankara and Alaca Höyük, Palæozoic, Triassic and Jurassic rocks in the condition of a tectonic mélange are overlain unconformably by Upper Cretaceous and Eocene; while, in associated synclinals at Ayas and Kirsehir, crystalline schists and granites, probably Palæozoic or earlier, emerge from beneath unconformable Oligocene. It is suggested that these crystallines are parts of a Pontic nappe which advanced southwards during Upper Cretaceous times, in part overriding and breaking local rocks to yield the Ankara Mélange, in part bulldozing them forwards to form the Taurus Mountains. The displacement along the Anatolian Thrust at the base of the invading Pontic nappe is reckoned at about 350 km.