• Using the 14C Bomb Pulse to Date Young Speleothems

      Hodge, Ed; McDonald, Janece; Fischer, Matthew; Redwood, Dale; Hua, Quan; Levchenko, Vladimir; Drysdale, Russell; Waring, Chris; Fink, David (Department of Geosciences, The University of Arizona, 2011-01-01)
      Three modern speleothems were sampled at high resolution for radiocarbon analysis to identify their bomb-pulse signatures and to construct chronologies. Each speleothem exhibited a different 14C response, presumed to be related to site characteristics such as vegetation, temperature, rainfall, depth below the surface, and water pathway through the aquifer. Peak 14C activity for WM4 is 134.1 pMC, the highest cited thus far in the literature and suggestive of a lower inertia at this site. Dead carbon fractions for each stalagmite were calculated and found to be relatively similar for the 3 speleothems and lower than those derived from Northern Hemisphere speleothems. An inverse modeling technique based on the work of Genty and Massault (1999) was used to estimate soil carbon residence times. For each speleothem, mean soil 14C reservoir ages differed greatly between the 3 sites, ranging from 2-6.5 to 32-46 yr.
    • Who's That Lying in My Coffin? An Imposter Exposed by 14C Dating

      Sowada, Karin; Jacobsen, Geraldine E.; Bertuch, Fiona; Palmer, Tim; Jenkinson, Andrew (Department of Geosciences, The University of Arizona, 2011-01-01)
      In the 19th and early 20th centuries, many museums acquired Egyptian coffins containing mummies from private donors who bought them from dealers in Egypt. Owing to the unknown context of such acquisitions, it cannot be assumed that the mummified individual inside the coffin is the same person named on it. Radiocarbon dating is a key diagnostic test, within the framework of a multidisciplinary study, to help resolve this question. The dating of an adult mummy in the Nicholson Museum at the University of Sydney was therefore checked using 14C dating. For over 150 yr, mummy NM R28.2 was identified as Padiashaikhet as per his coffin, dated to the 25th Dynasty, about 725-700 BC. 14C results from samples of linen wrappings revealed that the mummy was an unknown individual from the Roman period, cal AD 68-129. The mummification technique can now be understood within its correct historical context.