Investigation of Hoz-e-Soltan with sedimentary cores in Holocene

Hoz-e-Soltan playa catchment area 195 km2, depth 25-50 cm, is located 85 km southwest of Tehran. The objective of this research was to determine the paleoclimate and water table fluctuations in Holocene through sedimentary facies studies. In this research, 9 cores (maximum length of 7 meters) were taken from the lake substrate, and then facies investigations, such as sediments’ characteristics, organic matter contents, colors, crystals of evaporative minerals and sedimentary sub-environment were determined. 155 subsamples were prepared from different sedimentary facies, and then granulometric analysis and mineralogy (XRD) were carried out. Results indicated that there are 5 sedimentary subenvironments,including sand flat, mud flat, saline mud flat, salt pan and ephemeral lake in the studied cores. On the basis of granulometry results, 5 sedimentary types were recognized in the subsurface sediments; slight gravel-bearing sandy mud, slight gravel-bearing muddy sand, mud, sandy mud and muddy sand. Sedimentary sub-environments of HS1 and HS2 cores are in relation to saline-mud flat and mud flat environment, respectively. Also, during Holocene lake water table fluctuation were drown and wet and dry period sediments were defined. Result shows that 6 major drought period exist in this region so during the last few thousand years, the lake had wet and dry conditions. Recent climate change and globalwarming doesnt serious effect on more drying of the lake; these wet and dry periods were frequently repeated.