Holocene large mammal mass death assemblage from South Africa

Abstract

A fossilised large mammal bonebed was discovered eroding out of a gully in the Free State of South Africa. The bonebed is ~1.5 m below the modern land surface, and extends over an area 35 × 13 m. Surface scatters of stone tools occur in a 1 km radius of the site, and a large fire place associated with spirally fractured burnt bone is preserved to one side. The purpose of this research was to excavate and taphonomically analyse the faunal sample to elicit the cause of death, and radiocarbon date it to establish when it happened. The bonebed is represented by black wildebeest, including juvenile and adult individuals. Faunal remains are randomly oriented and many are complete. Weathering stage 1 on most of the bones together with the articulation pattern suggest that the carcasses were exposed for more than a year and less than three before being buried by hillslope sediment. Two-thirds of those fractured record a spiral breakage pattern. There are a few trample marks on bones and evidence of some termite activity. No stone tools were found in the section of bonebed we excavated, and there is no evidence of manmade or carnivore damage on the fauna. Calcrete nodules in the underlying deposits and phytoliths representative of desertification throughout the sedimentary sequence suggest that the animals died under drought conditions between 3840 ± 40 and 3500 ± 40 cal BP, and that human activity at the site was marginal.