Reading Archaeologist re-dates Ancient Near East – University of Reading10 December 2001
New radiocarbon dating estimates for the eastern Mediterranean and Aegean may resolve key debates about the history of the region during the third to first millennia B.C. Radiocarbon dates from tree rings are routinely used to date ancient archaeological sites, but they assume that the carbon absorbed by all mid-latitude trees contains the same percentages of carbon isotopes, even though the trees' growing seasons may occur at different times of the year.
Two international studies released this week by Science (ScienceExpress 6 December) identify small regional differences in carbon-14 ratios, which shift several important dates for key artefacts in the ancient Near East. This research was carried out by the East Mediterranean Radiocarbon Intercomparison Project (EMRCP), based at Reading, and directed by Dr. Sturt Manning of the Department of Archaeology. The significance of these two papers and research is discussed in a Perspective paper by Paula Reimer (Lawrence Livermore National Laboratory).
In one paper Bernd Kromer (Heidelberg), Sturt Manning (Reading), and Peter Kuniholm (Cornell) and colleagues found that trees growing in Turkey during the 15th to 17th century AD have carbon-14 ages up to 17 years older than German trees of the same calendar age. The difference is probably due to the way that the Spörer solar minimum (during which carbon-14 production was high) affected the production rate of carbon-14 in the atmosphere and the seasonal cycle of tree growth in the two regions. Similar effects should occur during other periods of rapidly changing atmospheric radiocarbon inventories, according to the authors. The authors thus highlight the importance of short-term episodes of regional 14CO2 offsets to palaeoclimate studies.
In a second paper, Sturt Manning, Bernd Kromer, Peter Kuniholm and Maryanne Newton (Cornell) used these findings to re-evaluate a critical floating tree-ring sequence from timber in Anatolian archaeological monuments, spanning roughly the third through the first millennia B.C. After re-calibrating this record in a way that accounts for a period of rapidly increasing carbon-14 in the atmosphere, they found that the chronology is 22 years older than previously thought. Over 20 key archaeological monuments/sites are redated, including the Sarikaya Palace at Acemhöyük, Turkey, built ca. 1774 B.C., and containing an archive with well over a thousand written texts referring to key historical individuals, and the famous Uluburun shipwreck off the south coast of Turkey from shortly after ca. 1327 B.C. from which a gold scarab of the Egyptian Queen Nefertiti was recovered. Among other things, this work resolves over a century of debate about Mesopotamian chronology between no less than five major rival schemes and estimates varying by as much as 300 years. Key historical figures, such as Hammurapi the Law Giver, are anchored by this work.
Manning et al. also date an extraordinary growth anomaly in the Anatolian tree-ring record to 1650 +4/-7 B.C. The authors suggest that this may well reflect the great eruption of the volcano of Thera (Santorini) in the Aegean Sea. The new dates have important implications for the synchronisation of the civilisations of the Near East and eastern Mediterranean in the second millennium B.C.
The papers are online at: http://www.sciencemag.org/sciencexpress/recent.shtml
The papers are formally published in printed form in the journal Science in a few weeks.
For further details, please contact Sue Rayner or Carol Derham on 0118 378 8004/5 Fax 0118 378 8924.