Search of Natural Fullerenes in Chinese Coal Layers

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Debates on the existence of fullerenes in nature still remain unsettled. Concentration levels of C_<60> allegedly detected in black geological layers like KT and PT or from carbon-containing rocks collected from meteorite impact craters are generally less than 0.1 ppm and are difficult to confirm. The only case that reports sufficiently high natural fullerene concentrations is a coal sample taken from Yipinglang coal mine in Yunnan, China. Unfortunately the information on this rare sample was rare and inaccurate. The purpose of this search is to confirm the report by our own survey.Three survey trips were made with geologists to not only the Yipinglang mine but also to the other coal mines in China to collect coal samples ourselves. A final trip was made to South Africa where novel coal beds intruded by magmas and the world's oldest and largest meteorite crater were surveyed.The results are as follows. (1) Only the Yipinglang coal sample that had been reported to contain C_<60> was con … More firmed to contain as high as 0.3 % of C_<60>/C_<70>. This particular coal sample was found to contain, in addition to fullerenes, soot-like microstructure of nano-sized graphitic nanoparticles, and two kinds of new minerals, probably a high temprature-high pressure modifications of known minerals. (2) All other samples collected were negative with respect to the fullerene analysis.In spite of these results, we were not allowed to enter the underground mine for the reason of safety, neither to study 3D underground maps. However, after patient and long negotiations, we eventually succeeded in obtaining large number of coal samples from Yipinglang mine whose exact underground locations were recorded. Preliminary tests on a time-of-flight mass spectrometer proved positive for a few samples among them and currently work is going on for quantitative analysis with a HPLC.Based on several pieces of evidence, we propose natural shock compression as the cause of formation of C_<60> in coal. Strong evidence is available for the verification of the formation of C60/C70 in a shock tube experiment. We are in the process of cooperative research with National Aerospace Laboratory to study the formation of fullerenes upon irradiation of plasma jet stream onto graphite surface in a heated wind tunnel. Less