A 14C chronology for the Middle to Upper Palaeolithic transition at Bacho Kiro Cave, Bulgaria

The stratigraphy at Bacho Kiro Cave, Bulgaria, spans the Middle to Upper Palaeolithic transition, including an Initial Upper Palaeolithic (IUP) assemblage argued to represent the earliest arrival of Upper Palaeolithic Homo sapiens in Europe. We applied the latest techniques in 14C dating to an extensive dataset of newly excavated animal and human bones to produce a robust, high-precision radiocarbon chronology for the site. At the base of the stratigraphy, the Middle Palaeolithic (MP) occupation dates to >51,000 yr bp. A chronological gap of over 3,000 years separates the MP occupation from the occupation of the cave by H. sapiens, which extends to 34,000 cal bp. The extensive IUP assemblage, now associated with directly dated H. sapiens fossils at this site, securely dates to 45,820–43,650 cal bp (95.4% probability), probably beginning from 46,940 cal bp (95.4% probability). The results provide chronological context for the early occupation of Europe by Upper Palaeolithic H. sapiens.