This study aims to investigate Sabzevar playa in the northeast of the Great Kavir in terms of geomorphology, bulk and clay mineralogy, as well as the geochemistry of core sediments from the surface to a depth of 1m. The results suggest that up to 50% of Sabzevar playa is made of clastic components (mostly quartz and clay minerals), which increases toward the depth, though this trend is bucked by evaporite minerals (mostly gypsum, calcium carbonate, and halite). According to the mineralogical trend and geochemical evidence, Sabzevar brine has evolved into a Na–SO 4 –Cl type. Granulometry studies suggest drastic fluctuations and higher energy costs during sediment deposition at a depth of 1m compared to the surface. The micro-morphology of quartz grains is due to the windborne surface sediments and waterborne deep grains. A combina- tion of clay mineralogy and geochemistry of elements exhibits a higher evaporation rate at the surface than at a depth of 1m, suggesting that the area has witnessed a climate change from a warm humid climate in the past to a warm arid climate in recent years. Sabzevar playa is characterized by an unconventional Bull’s-eye pattern with a concentration of calcite around the playa, gypsum in the center, and halite in the west. This research also explores the hydrological characteristics of the study area based on geomorphologic surfaces findings revealing that the groundwater level was higher in the west than in the center and east of Sabzevar playa, leading to the formation of halite and the development of a salt pan in the margin.

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