Asymmetric X-ray diffraction peak of metamorphosed carbonaceous material |
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| Authors: | Tetsumaru Itaya Morio Tomuro Kiyotaka Ninagawa |
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| Institution: | Department of Geology, University of Auckland, Private Bag, Auckland, New Zealand;Department of Applied Physics, Okayama University of Science, 1–1 Ridai-cho, Okayama 700, Japan |
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| Abstract: | Abstract It was revealed that the asymmetric X-ray diffraction peak of metamorphosed carbonaceous material was a combination of two types of symmetric peaks from the coaly material and graphite crystallite. Numerical synthesis using the two symmetric peaks shows the graphitization process observed in a metamorphic sequence is accompanied by a continuous change of the peak shape and apparent interplanar spacing. Based on the analytical results and geological observations, it is suggested that graphitization of carbonaceous material consists of two processes: (i) the formation of graphite crystallites at the expense of the coaly material through the formation of transitional material and the increasing abundance of crystallites which is observed in the chlorite zone; and (ii) growth of crystallites forming well-ordered graphite, which occurs in the higher-grade zone. |
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| Keywords: | asymmetric XRD peak graphitization process metamorphosed carbonaceous material numerical analysis Sanbagawa schist |
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