Facies characteristics and depositional environments of Quaternary tufa deposits, Antalya, SW Turkey

Abstract

This study describes the facies characteristics and the origin of widespread tufa deposits in Antalya Quaternary Basin in southwestern Turkey. The tufa formation covers an area of 630 km2 and is up to 280 m thick. Its generation is related to three major terrace systems that developed during the Quaternary. The upper (240–315 m) and the middle terraces (sloping seaward from 40 to 150 m) are exposed above sea level, while the lower terrace is below sea level (−100 to −50 m). The Antalya tufas are classified into ten facies according to the lithological and petrographic characteristics as phytoherm framestone (Pf), boundstone a-phytoherm boundstone (Pb), b-stromatolitic-like tufa (Sl), bedded micritic tufa (M), phytoclastic (Pc), oncoidal tufa (O), intraclastic tufa (I), microdetrital tufa (Md), palaeosols (Ps), pisolitic tufa a-channel type (P), b-pool type (Pp) and intraformational tufa conglomerate (Ic). Process oriented facies analyses, scanning electron microscopy (SEM) and isotopic studies indicate fluvial, marsh, lacustrine and waterfall/cascade depositional environments, all formed through biological and physicochemical effects under cool (ambient) water conditions. Stable isotopic data (δ18O, δ13C) of Antalya Tufa is indicative of cold-water conditions, which are affected by seasonal temperature changes. The 230Th/234U ages obtained from the lower parts of the middle terrace indicate that the deposition started at least prior to 380 ka. On the other hand, 14C ages (16.85 and 3.56 ka) obtained from the upper parts of the middle terrace indicate that the deposition lasted till at least 3.56 ka. The upper terrace tufa deposition occurred during Early-Mid Quaternary by tectonic uplift. Following the deposition, the first escarpment was probably formed in Mid Quaternary. Lower and middle terrace depositions are both controlled by eustatic sea level changes and tectonic uplift that occurred during Mid-Late Quaternary. The formation of the second escarpment at the lower terrace (Latest Pleistocene-Holocene) by glacio-eustatic sea level rise is followed by the formation of the third escarpment in the middle terrace (Holocene to Recent) by tectonic uplift and coastal cliff erosion.