A multiproxy study of the early Pleistocene palaeoenvironmental and palaeoclimatic conditions of an anastomosed fluvial sequence from the Çameli Basin (SW Anatolia, Turkey)

Abstract

A multiproxy study of the anastomosed fluvial succession from the Çameli Basin (SW Anatolia, Turkey) provides new insights on the palaeoenvironmental and palaeogeographical evolution of an extensional basin located at the top of western Taurides mountain range in the eastern Mediterranean. Detailed sedimentological, palaeontological and geochemical analyses on biogenic carbonates were carried out on the early Pleistocene (latest Villanyian) organic-rich fluvial succession in the Bıçakçı locality. Five main facies association groups characteristic of different sedimentary environments are recognized: (i) channel (CH), comprising lens-shaped bodies of fine- to medium-grained sandstones with minor siltstone interlayers; (ii) crevasse-splay (CS), including laminated siltstones and fine- to medium-grained sandstones sheets; (iii) pond (PD), containing laminated carbonaceous shales interbedded with siltstone or sandstone; (iv) swamp (SW), comprising coal beds with siltstone interbeds; and (v) floodplain (FP), including massive mudstones interbedded with siltstone and sandstone beds. Detailed facies analysis of the Bıçakçı succession reflects deposition on a floodplain which was traversed by a network of low-energy, well-defined channels separated by swamp and ponded areas in an anastomosed fluvial system. The Bıçakçı succession comprises a very rich micromammal fauna with a few large mammal remains, a rich variety of molluscs, plant macrofossils and pollen. This comprehensive record allows a multiproxy approach in reconstructing the early Pleistocene palaeoenvironment. The fauna and flora and stable isotope composition of the mollusc fauna of the Bıçakçı succession reflect vegetated quiet to slow moving freshwater shallow lakes and swamps under mostly cold and arid climatic conditions (stages 1 and 3) interrupted by a warm and subhumid interval (stage 2). The multiproxy record from Bıçakçı shows that early Pleistocene palaeoenvironments were predominantly open, steppe with some isolated shrubs and trees with forest at higher elevations. The very diverse landscape mosaics in the Çameli Basin during the early Pleistocene provided an excellent setting for refugia of Eurasian taxa. The biogeographic signature of mollusc and plant biota is predominantly modern Palaearctic with a minor amount of modern Palaearctic of the eastern Mediterranean, whereas mammal biota are dominated by extinct Palaearctic with a low proportion of the modern Palaearctic. During the early Pleistocene (2.25–2.1 Ma), the palaeoclimate and palaeoenvironmental conditions in Bıçakçı correspond to climatic deterioration after the onset of northern hemisphere glaciation (NHG, ~ 2.55 Ma) in the eastern Mediterranean. © 2016 Elsevier B.V.