The problem with radiocarbon dating
The enclosures of Layer III were treated in a special way at the end of their use lives.
They were cleaned, part of their fittings dismantled, and refilled.
These differences are most obvious in a certain find category: projectile points.
Very detailed categorization schemes have been elaborated meanwhile, based on material from sites throughout the Near East.
Although the observed archaeological stratigraphy is confirmed by the relative sequence of the data, absolute ages are clearly too young, with Layer III being pushed into the 9th millennium, and Layer II producing ages from the 8th or even 7th millennia cal BC.
Layer III, the lower and thus older layer, has the famous circular enclosures with the T-shaped pillars.
Layer II is characterized by smaller buildings with rectangular groundplans.
They serve as ‘guiding fossils’ for dating (yes, early archaeologists borrowed this term from geology).
At Göbekli Tepe, we can differentiate two layers which are completely different in the type of architecture appearing in them.