Yarim-ghayeh cave, located in the border of Iran and Turkey, is hosted by the Oliogocene-Miocene limestone  body.  Its in and outside rough topography implies that the cave is  very young and infact in the beginning  stage of its formation. Overall volume is 9600 m³  with 631 m²  dry area and 4700 m³ occupied by water with 4 to 6 meters in depth.  Structurally, the cave has been formed by a fault system cause a sinkhole form on the top of the cave aproximately of 10000 m².  Its water is clean and clear with pH of 7.36  and its fluorine is only 1.7 ppm  compared to 4.5 ppm in Maku area.
     Yarimghayeh playa  with an area of 5 m² is in the close eastern part of the cave  with permenant water flow.  Elevation of the water surface of playa is 1414 m which is 2 m higher than the water surface of the cave (1412  m).  500 m³ water is daily pumped out without any change in water level. Since there is no any other water flowing to the cave, therefore, the playa is supplying the cave water system. The ecosystem  of the cave and playa are tight  together and any change in one will affect the other.  To protect its water quality from contamination, access to this  small scale cave must be restricted except for scientific research.