Lithostratigraphy of Border Cave, KwaZulu, South Africa: a Middle Stone Age sequence beginning c. 195,000 b.p.

Border Cave is well-known for its Middle Stone Age (MSA) sequence and associated hominids, as well as for the earliest demonstrable Later Stone Age (LSA) (c. 38,000 b.p.) strata in southern Africa. Detailed lithostratigraphic and sedimentological study permits identification of 8 Pleistocene sedimentary cycles, including 6 major cold phases and 2 intervening weathering horizons. The 2 youngest cold phases are associated with the LSA and have 8 ¹⁴C dates 38,600-13,300 b.p. By gauging sedimentation rates in finer and coarser sediments, duration of sedimentary breaks, and allowing for differential compaction, the excellent radiocarbon framework provided by 28 available ¹⁴C dates can be extrapolated to the 6 cold intervals and 2 palaeosols that are older than 50,000 b.p. These clearly span oxygenisotope stages 4, 5 and 6, placing the base of the MSA deposits at c. 195,000 b.p., Homo sapiens sapiens at c. 90,000–115,000 b.p. and the sophisticated, microlithic “Howieson's Poort” industry at 95,000 b.p. These results require radical reassessment of the age and nature of the MSA complex and of the earliest evolution of anatomically-modern people.