Mid-Holocene climate and high-elevation environments during the Later Stone Age occupations of Beefa Cave (Melka Kunture, Upper Awash, Ethiopia)

This study presents stable carbon and oxygen isotope data from bovid tooth enamel recovered from level 1 of Beefa Cave (~5 ka), a Later Stone Age site located at 2000–2200 m a.s.l. within the Melka Kunture complex on the Ethiopian highlands. Bulk and intra-tooth sequential samples on bovid teeth were used to reconstruct the diet, vegetation structure, and seasonal hydroclimatic variability. Carbon isotope values indicate a strong reliance on C4 grasses, while pronounced intra-tooth oxygen values oscillations document marked seasonal variability in water availability during enamel mineralization. Compared with the Early and Middle Pleistocene isotopic records from Melka Kunture, the mid-Holocene specimens exhibit substantially higher carbon and oxygen values, reflecting a long-term shift from wetter, mixed C3-C4 environments to more open, seasonally dry high-elevation landscapes. Comparisons with contemporaneous sites in Africa further highlight pronounced spatial heterogeneity in environmental responses at ~5 ka. These results provide new insights into Holocene ecological reorganization of the Ethiopian highlands and the environmental contexts of Later Stone Age hunter-gatherer occupations.