New insights on the Antalya Nappes in the apex of the Isparta Angle: the Isparta Çay unit revisited

Abstract

AbstractThe Isparta Çay unit was defined in the valley of the Isparta Çay (river) as one of the units that constitutes the Antalya Nappes. Situated structurally between the Bey Dağları autochthon and the Miocene neo‐autochthon, the Isparta Çay unit provides decisive arguments with respect to the timing of emplacement of deep basinal units, cropping out in the central part of the Isparta Angle, as well as for a model of reconstruction of the Pamphylian Basin, located to the south of the Taurus belt. The Isparta Çay unit (previously named ‘Isparta Çay formation’) consists of a pile of thrust sheets all of which display the following basic sedimentary sequence: Triassic marls and sandstones containing plant remains and limestones with Halobia, overlying Jurassic to Cretaceous deep‐sea sedimentary rocks (radiolarites). Detailed mapping, combined with new and revised stratigraphic data, confirms the existence of a very complex pile of tectonic, rather thin sheets. The basic sequence is composed, from bottom to top, of the following sedimentary units: (1) marls and turbiditic sandstones rich in plant debris; (2) limestones interbedded with marls and; (3) regularly‐bedded cherty limestones. These three lower units contain rather abundant fossils (i.e. Halobia and ammonites) and are Triassic in age: (4) lenticular calcareous breccia in which Middle Jurassic foraminifera are found; (5) radiolarites, green and then red, including lenticular beds of reworked calcareous sands (now dolomitized and/or silicified). The radiolarians from the red radiolarites establish a Jurassic to Early Cretaceous age and; (6) red silts and clays with interbedded calcareous breccia, which are probably Cretaceous in age. The total thickness of the basic sequence as described above varies between 100 and 150 m, depending on the thickness of the lenticular breccia intercalations.Such a sequence is frequent in the Antalya Complex as one of the deep basinal sequences. It has been interpreted as one sequence expelled from the Pamphylian Basin, located between the Anamas–Akseki platform (Western Taurus) to the NE, and the Bey Dağları platform to the SW. The age of the radiolaritic sequences of the Antalya Nappes, extended to all the units of SW Turkey, is discussed. Copyright © 2003 John Wiley & Sons, Ltd.