Göbleki Tepes is much older than Sumer or anything in Mesapotamia.
Sumer, the very first civilisation in Mesopotamia, started around 5.000 BC.
Göbelki Tepes, in Turkey, is from around 8000 - 9.500 BC.
Do the math, which one is older?
This is why Göbelki Tepes is so interesting, it´s dated to when there shouldn´t have been any civilisations, and yet there it is.