Sedimentology and stratigraphic sequence of the Gavkhoni playa lake, SE Esfahan, Iran

The Gavkhoni playa lake is surrounded by alluvial fan deposits to the north, south and east and the Varzaneh aeolian sand field to the west. Four major sub-environments including: sand flat/saline sand flat, sand beach, mud flat/saline mud flat and salt pan and seven major facies can be recognized in this playa lake. Sand flat results from transportation of sand by wind from the adjacent sand dunes. The mud flat reflects rapid deposition on a lower flood plain during wet, shortly after sheet floods. The saline mud flat and salt pan is as a result of three stages: flooding, evaporation and desiccation. After flooding, when the shallow ephemeral lake becomes concentrated by evaporation, saline mud flat is formed and finally the formation of salt pan starts.Regarding the sub-environments it is supposed that climatic changes played an important role in sedimentation. During periods of increased run off, sedimentation of alluvial/fluvial occurred and water table was raised at the playa lake. During periods of reduced run-off and falling water table, the saline mud flat and salt pan were formed and wind erosion of alluvial deposits resulted in formation of sand dune and sand flat.