The Late Quaternary sedimentary sequences and environmental changes based on core studies in the Gavkhouni Playa (Central Iran)

The Gavkhouni Playa is located in the lowlands of the Esfahan Plain, Central Iranian Plateau. The history of late Pleistocene to Holocene sedimentary evolution, and paleo-geomorphology and paleogeography of the Playa were investigated in this study. To cover the playa area 16 intact sediment cores, at a maximum depth of 11.30 m were collected by a hand-auger. These undisturbed cores were analyzed to identify their facies based on macroscopic features such as texture, structure, composition of evaporite minerals, color, and organic materials. The analysis was run on the vertical and spatial distribution of sedimentary facies and surrounding areas for two different zones, herein. The findings indicate eight facies within five main sedimentary environments including aeolian, playa, lake, delta, and river. The chronological control is provided by the Carbon-14 Accelerator Mass-Spectrometric (14C AMS) method. According to the result of 14C dating, the sedimentation rate is 0.4 mm/year and 0.25 mm/year in the western and eastern parts, respectively. The studies on the sub-surface facies reveal that the investigation area was subjected to wet and dry periods over the last 30 ka cal BP. Four dry periods were identified in 11,600, 8200, 4200, and 1000 cal BP, and one wet period in 3500 cal BP. It is assumed that the eastern and northern parts of the area had conditions like that to today, at least for the last 1000 years.