Maranjab desert is located 4 hours driving from Tehran to Aran & Bidgol city. Then less than one hour (40KM) driving in a dirt road to Maranjab Caravanserai.
This Carvanserai was built around 350 years ago during the days of King Abbas I of Persia. The purpose of this Caravanserai was to protect travelers of that time from the robbers and to provide shelter and water.
It is currently a tourist attraction.
The Sargardan (Wandering) Island is in the Maranjab desert. You should consider that the lake is entirely flat and dry at some parts of the year. The water does not evaporate or freeze at the other times since it is too salty.
The maximum dept of lake is just few centimeters. There is no risk of drowning. Though it is not safe to go there by SUVs without guides. Due to presence of high level of mineral salt, beautiful natural Hexagonal pieces form on the surface.
Reference:
http://www.yjc.ir/fa/news/4569369
http://blog.mirjamali.com/en/blog/2013/01/13