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Chronology

Radiocarbon dating shows that the earliest exposed structures at Göbekli Tepe were built between 9500 and 9000 BCE, towards the end of the Pre-Pottery Neolithic A (PPNA) period. The site was significantly expanded in the early 9th millennium BCE and remained in use until around 8000 BCE, or perhaps slightly later (the early Pre-Pottery Neolithic B, PPNB). There is evidence that smaller groups returned to live amongst the ruins after the Neolithic structures were abandoned.

Schmidt originally dated the site to the PPN based on the types of stone tools found there, considering a PPNA date "most probable". Establishing its absolute chronology took longer due to methodological challenges. Though the first two radiocarbon dates were published in 1998, these and other samples from the fill of the structure dated to the late 10th and early 9th millennium – 500 to 1000 years later than expected for a PPNA site. Schmidt's team explained the discrepancy in light of their theory that this material was brought to the site from elsewhere when it was abandoned, and so was not representative of the actual use of the structures. They instead turned to a novel method of dating organic material preserved in the plaster on the structure's walls, which resulted in dates more consistent with a PPNA occupation, in the middle or even early 10th millennium BCE. Subsequent research led to a significant revision of Schmidt's chronology, including the abandonment of the hypothesis that the fill of the structures was brought from elsewhere, and a recognition that direct dates on plaster are affected by the old wood effect. Together with new radiocarbon dates, this has established the site's absolute chronology as falling in the period 9500 to 8000 BCE – the late PPNA and PPNB.