Why are the Kopet Dag Mountains (on the border between Iran and Turkmenistan) coloured much like the Bulgarian flag?

[Link to satellite imagery in Google Maps]
(Location is 37.548903 North, 59.033423 East)
Why are the Kopet Dag Mountains (on the border between Iran and Turkmenistan) coloured much like the Bulgarian flag?

[Link to satellite imagery in Google Maps]
(Location is 37.548903 North, 59.033423 East)