But a rainbow is a very well known symbol no matter which culture you are from
I think the only reason that the Rainbow is there is so that the disc can be aligned the right way. After all if you don't know which way up to hold the map its next to useless.
Once the rainbow is aligned the right way everything becomes clear
just beneath that is the pleides and in a nw position you have Orion. These two constellations allow you to discover where the disc was constructed. If we allow that Orion represents the egyptian culture then the centre of the disc sits precicesly south east of it.
So the origin of the disc is south east of egypt. Theres only one culture in that direction and its mesopotamian.
Now the disc has been dated to the bronze age because bronze and gold make up its component parts. so it could date from the time of the bronze age in the area it was found which places it around 2000bce. Personally i would place it at the date of the bronze age where it was created. that places it anytime after 3500bce. Funnily enough right at the same time that standing stone circles were being built all over europe and indeed the disc was found right next to one. Nobody knows who is responsible for the stone circle enigma.
Well this week anyway.
The sumerians always depicted the pleides like that
only they called it MUL.MUL