The age of fossil StW573 ('Little Foot'): An alternative interpretation of 26Al/10Be burial data

Jan D. Kramers, Paul H.G.M. Dirks

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Following the publication (Granger DE et al., Nature 2015;522:85-88) of an 26Al/10Be burial isochron age of 3.67±0.16 Ma for the sediments encasing hominin fossil StW573 ('Little Foot'), we consider data on chert samples presented in that publication to explore alternative age interpretations. 10Be and 26Al concentrations determined on individual chert fragments within the sediments were calculated back in time, and data from one of these fragments point to a maximum age of 2.8 Ma for the sediment package and therefore also for the fossil. An alternative hypothesis is explored, which involves re-deposition and mixing of sediment that had previously collected over time in an upper chamber, which has since been eroded. We show that it is possible for such a scenario to yield ultimately an isochron indicating an apparent age much older than the depositional age of the sediments around the fossil. A possible scenario for deposition of StW573 in Member 2 would involve the formation of an opening between the Silberberg Grotto and an upper chamber. Not only could such an opening have acted as a death trap, but it could also have disturbed the sedimentological balance in the cave, allowing unconsolidated sediment to be washed into the Silberberg Grotto. This two-staged burial model would thus allow a younger age for the fossil, consistent with the sedimentology of the deposit. This alternative age is also not in contradiction to available faunal and palaeomagnetic data.

Original languageEnglish
Article number20160085
JournalSouth African Journal of Science
Volume113
Issue number3-4
DOIs
Publication statusPublished - 1 Mar 2017

Keywords

  • Australopithecus prometheus
  • Burial dating
  • Burial history
  • Cosmogenic nuclides
  • Muons

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Agricultural and Biological Sciences
  • General Earth and Planetary Sciences

Fingerprint

Dive into the research topics of 'The age of fossil StW573 ('Little Foot'): An alternative interpretation of 26Al/10Be burial data'. Together they form a unique fingerprint.

Cite this