CHARRED remains of ancient rainmaking fires are helping to date droughts in Iron Age Africa to within 20 years.
After a several years of little or no rainfall, the Bantu people near modern-day Zimbabwe would send a rainmaker to nearby hills. 鈥淭hey鈥檇 burn fires with dark smoke to call black rain clouds from the mountains,鈥� says Thomas Huffman at the University of the Witwatersrand in Johannesburg, South Africa. Villagers were also made to burn grain bins if they had planted 鈥渦nlucky鈥� foreign seeds.
Huffman鈥檚 team uncovered the ashes within archaeological remains. With the help of carbon dating and analysis of tree rings they discovered and dated previously unknown droughts (Journal of Archaeological Science, ).
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The results also date a drought in AD 1300 thought to have made a Bantu society vulnerable to invasion from Great Zimbabwe.
