Newly discovered fossil- and artifact-bearing deposits, uranium-series ages, and Plio-Pleistocene hominids at Swartkrans Cave, South Africa

Abstract

We report on new research at Swartkrans Cave, South Africa, that provides evidence of two previously unrealized artifact- and fossil-bearing deposits. These deposits underlie a speleothem dated by the uranium-thorium disequilibrium technique to 110,000 ± 1,980 years old, the first tightly constrained, geochronological date available for the site. Recovered fauna from the two underlying deposits—including, prominently, the dental remains of Paranthropus ( Australopithecus) robustus from the uppermost layer (Talus Cone Deposit)—indicate a significantly older, late Pliocene or early Pleistocene age for these units. The lowest unit (LB East Extension) is inferred to be an eastward extension of the well-known Lower Bank of Member 1, the earliest surviving infill represented at the site. The date acquired from the speleothem also sets the maximum age of a rich Middle Stone Age lithic assemblage.