Cryptotephra Discovered at Pinnacle Point Site 5-6 May Correlate with the 74 ka Eruption of Toba in Indonesia: Implications for Resolving the Dating Controversy for Middle Stone Age Sites in Southern Africa.

Summary

Cryptotephra was identified in a sediment stack at Pinnacle Point Site 5-6, South Africa, and occur as small glass shards (less than 100 µm in size). Shards are found in sediment from the Shelly Ashy Dark Brown Sand (SADBS) and the Ashy Light Brown Sand (ALBS) layers with weighted mean OSL dates of 70.6 ± 2.3 and 71.1 ± 2.3 ka respectively. The shards are intimately mixed with sediment and are rare. A preliminary shard distribution profile shows that shards are distributed continuously through the section in two broad peaks separated by a zone of zero shards within the lowermost SADBS. Major element analyses performed on several shards using electron probe microanalysis indicate that they are rhyolite with SiO2 varying from 72.15 to 77.56 wt. %. Major element chemistry is similar to distal tephra of the ~74 ka eruption of Toba volcano in Indonesia providing for the first time, evidence that Toba ash may have reached southern Africa. The discovery of cryptotephra at PP5-6 provides a powerful new method to create a precise chronological tie-point between archaeological sites and to help identify when a suite of uniquely human features first appeared in our evolutionary history.

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This Resource is Part of the Following Collections

• Building the hunter-gatherer’s paleoscape on the South African coast: Environment, landscape, and foraging resources   •
• Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)

Keywords

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