John Anthony Jamys Gowlett

Kilombe is an extinct volcano in the central Rift Valley of Kenya, with a central caldera formed through a large collapse of the mountain in a past eruption. Our palaeoanthropological research involves exploring clear traces of early hominin activities first found high within the caldera in 2016. Multiple lines of evidence including radiometric dates indicate ages of at least 1.7-1.8 million years, approximately the age of Bed I to Lower Bed II at Olduvai Gorge in Tanzania. Repeated falls of volcanic ashes in a long succession have covered clay land surfaces within the caldera, creating contexts reminiscent of those of the well-known Olduvai site FLK, and preserving fossil animal bones. Initial finds include an early stone tool occurrence in a rugged setting not previously known to have been occupied, and 500 m higher than other early Pleistocene sites in East Africa. In the research we are exploring the sediments, palaeontology and archaeology of the exposures in the caldera, so that we can work out their extent, character, and the range of early human activities, asking if the technology at the caldera sites is typical of the Oldowan tradition known from this period. We aim to investigate whether the repertoire of hominin activities has a distinctive character related to the high level, through comparing the evidence with finds from low level environments. The results will inform us about the socioecology of early Homo (and perhaps other hominin lineages, such as robust australopithecines), especially the nature of their adaptability at an early date. The Kilombe caldera environment affords a currently unique opportunity to test the hypothesis that early hominins were extensively using higher parts of the landscape as early as two million years ago.