Reconstructing Neolithic groups in Sarawak,Malaysia through lead and strontium isotope analysis

Heavy stable isotope analysis of mid-late Holocene Neolithic burials from Sarawak (Malaysia) identifies groups not apparent in mortuary treatment or inferred subsistence. Isotope ratios of strontium (⁸⁷Sr/⁸⁶Sr) and lead (²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, ²⁰⁶Pb/²⁰⁴Pb) from adult tooth enamel show distinct groups at Niah Cave's West Mouth organized by dietary catchment. Two roughly contemporary sites, Gua Sireh and Lobang Angin, are included to assess regional heterogeneity in northern Borneo. Heavy stable isotope ratios for humans differ from sampled modern plants and archaeological fauna from West Mouth, and suggest a non-local origin for some of the West Mouth human remains. Distinct heavy isotope ratios characterize all three sites and show regional differentiation broadly consistent with geological expectations. Results supplement paleodiet and morphological analyses and have implications for clarifying Niah Cave mortuary use during the mid-late Holocene. Further and more precise geographic placement will follow through additional landscape sampling for strontium and lead isotope values.