Radiocarbon Analysis for Dating of Parchment Material

摘要

Radiocarbon dating of an archeological parchment sample was carried out bycarbosorb and benzene synthesis methods. The sample, with few symbolic letters writtenon it, was claimed to belong to the Harappa civilization (ca. 3000-1500 BC).Objective: Carbosorb and benzene synthesis methods were optimized for radiocarbondating of parchment samples. Radiocarbon analysis conditions were optimized for liquidscintillation counter.Methods: Archeological parchment sample and a commercial parchment sample (controlsample) were processed by chemical and carbonization methods to remove inorganic andorganic impurities. Samples were converted into carbamate and benzene through carbosorband benzene synthesis systems, respectively. The conditions were optimized to achieve 74% efficiency of carbosorb method and 78% yield in benzene synthesis system.Results and Conclusion: The pMC of both samples were calculated by using statisticaltemplates. The fractionation in 14C for sample was corrected for and normalized to 13Ccomposition of -25 ‰ PDB by measuring the 13C composition of the sample, standard andbackground samples.The pMC of parchment sample, claimed to belong to old civilization, was calculated as119.3±1.4 in case of carbosorb method and 118.6 ±2.1 in case of benzene synthesissystem. Whereas, the commercial parchment sample showed pMC=121±3.4 for carbosorbmethod and pMC= 123±4.1 for benzene synthesis method. The age of parchment samplewas equal to 1958-1962 AD, when bomb NH3 calibration curve was applied. Based onresults, it was concluded that archeological sample was indeed have the post 1950 originand thus has nothing to do with ancient Harappa civilization.