Geology, mineralogy and geochemistry of Pleistocene-Holocene deposits in the Ciftlik Basin (Nigde) (Central Turkey)

The Quaternary basin fills of the Ciftlik (Central Anatolia, Turkey), comprised of partially lithified sediments, and was studied from drill cores to reconstruct the paleoenvironment of deposition as well as the timing of sediment accumulation. Six lithofacies were identified as (A) clast-supported gravel, (B) horizontally-bedded sand, (C) alternating silt-mud, (D) diatomite, (E) disrupted mud, (F) and tuff. The siliciclastic and diatomite facies were interpreted as fluvial-lacustrine deposits associated with a volcanic area (tuff) while the disrupted mud were identified as two types of paleosols: Inceptisols and Andisols. These paleosols are mainly composed of opal A, opal CT, quartz, feldspar, and clay minerals such as smectite, illite, and chlorite. The diatomite is mainly composed of opal A, opal CT, quartz, feldspar and clay minerals such as smectite. Weathering of the tuff resulted in consumption of SiO2, Al2O3+ Fe2O3, TiO2 and K2O by precipitation of smectite +/- illite in paleosols. SiO2 was enriched in the lake water for the accumulation of diatomite. The fossil diatom assemblages were mainly comprised of benthic, cosmopolitan, eutrophic, alkalibiontic, and mesosaprophic forms, living in a lake with open drainage, shallow depth, nutrient-rich waters, and high alkalinity. However, water level, salinity, alkalinity, and permanent of the lake level changed during the deposition of the diatomite.