Composition and origin of aeolian and fluvial sands of Gavkhuni playa lake (southeast of Isfahan)

Gavkhuni playa lake, located 130 km southeast of Isfahan, comprises of sand, mud and salt flats. This playa includes two environments as delta and playa lake. Sand dunes, 45 kilometers long, extend in the west of the playa. Rock fragments of andesite, dacite, tuff, granite, schist, gneiss, fossil bearing limestone, sandstone and also quartz and feldspar minerals form the alluvial and aeolian sediments. Heavy minerals including idocrase, tourmaline, biotite, wollastonite, magnetite, hematite, goethite and pyrite were also identified. Fesharak skarns located in northeast of the region are the sources of spinel, idocrase and wollastonite minerals. Silicate heavy minerals like hornblende, pyroxene, epidote, zircon, garnet, tourmaline, biotite and also magnetite are mainly originated from Urumieh-Dokhtar volcanic belt located in northeast of the area and different iron bearing rocks are the sources of pyrite, hematite and limonite. Therefore, lithology and its variation within the drainage basin and Zayandehrud River are important factors in the determination of kind and distribution of the alluvial and aeolian sands in the study area.