Concentrations of 'elemental carbon' in samples from the Peking Man Site at Zhoukoudian and the possibility of their application in the development of evidence for the use of fire by humans

摘要

"Elemental carbon" (EC) is a C-rich, O-H-S-N-depleted substance that is necessarily produced in the process of combustion. Due to the long-term use of fire by cave-inhabiting ape-men, considerable amounts of "elemental carbon" would be necessarily left behind in the corresponding strata inside the cave. The separation of EC was effected by the chemical method and the contents of carbon were determined on an element analyzer and a self-made measuring system. The concentrations of EC in the hearth, the exhibited ash samples collected from near the hearth unearthed in the 1930s, and the three samples of accumulated material collected from the tenth bed are 43.74 percent, 1.77 percent, 3.88 percent, 1.87 percent and 1.11 percent, respectively; those of the equivalent samples from the tenth bed outside the cave and samples from the fourth and seventh beds are at least one order of magnitude lower than the former's. The above results show that the sampling location of the tenth bed may be close to the hearth. Sampling over a wider range may lead to the finding of a location where the concentrations of EC are corresponding to the maximum values of EC in the hearth. The determination and study of EC may provide new evidence for the use of fire by Peking Man.