title: New cosmogenic burial ages for Sterkfontein Member 2 Australopithecus and Member 5 Oldowan.
abstract: The cave infills at Sterkfontein contain one of the richest assemblages of Australopithecus fossils in the world, including the nearly complete skeleton StW 573 ('Little Foot') in its lower section, as well as early stone tools in higher sections. However, the chronology of the site remains controversial owing to the complex history of cave infilling. Much of the existing chronology based on uranium-lead dating and palaeomagnetic stratigraphy has recently been called into question by the recognition that dated flowstones fill cavities formed within previously cemented breccias and therefore do not form a stratigraphic sequence. Earlier dating with cosmogenic nuclides suffered a high degree of uncertainty and has been questioned on grounds of sediment reworking. Here we use isochron burial dating with cosmogenic aluminium-26 and beryllium-10 to show that the breccia containing StW 573 did not undergo significant reworking, and that it was deposited 3.67 ± 0.16 million years ago, far earlier than the 2.2 million year flowstones found within it. The skeleton is thus coeval with early Australopithecus afarensis in eastern Africa. We also date the earliest stone tools at Sterkfontein to 2.18 ± 0.21 million years ago, placing them in the Oldowan at a time similar to that found elsewhere in South Africa at Swartkans and Wonderwerk.
authors.affiliation: Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Darryl E
authors.initials: DE
authors.lastname: Granger
authors.affiliation: Department of Anthropology, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Gibbon
authors.affiliation: 1] Evolutionary Studies Institute, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa [2] School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Kuman
authors.affiliation: Evolutionary Studies Institute, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Clarke
authors.affiliation: 1] School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa [2] French National Institute for Preventive Archaeological Research (Inrap), 561 rue Etienne Lenoir, km delta, 30900 Nîmes, France [3] University of Toulouse Jean Jaurès, UMR 5608 du CNRS (TRACES), Maison de la Recherche, 5 Allées Antonio Matchado, F-31058 Toulouse, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bruxelles
authors.affiliation: 1] Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, USA [2] Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Marc W
authors.initials: MW
authors.lastname: Caffee
mesh_terms: D000351:Africa, Eastern; D000535:Aluminum; D000818:Animals; D001608:Beryllium; D002048:Burial; D005580:Fossils; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry; D015186:Hominidae / Q000033:anatomy & histology / Q000145:classification; D010163:Paleontology / Q000379:methods*; D011868:Radioisotopes; D055110:Radiometric Dating / Q000379:methods*; D012863:Skeleton; D012886:Skull / Q000033:anatomy & histology; D013019:South Africa; D013997:Time Factors; D053001:Tool Use Behavior
chemical_list: D011868:Radioisotopes; D000535:Aluminum; D001608:Beryllium
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