著者

藤 加珠子 村江 達士 北島 富美雄

出版者

日本有機地球化学会

雑誌

Researches in organic geochemistry (ISSN:13449915)

巻号頁・発行日

vol.12, pp.21-26, 1997-05-30

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Some type of macerals in sediments fluoresces under ultraviolet light. According to an increase of their maturity level, the wavelength of fluorescence maximum sifts toward longer wavelength, and intensity of the fluorescence diminishes. This property allows the fluorescence spectra to be a good maturity indicator for low immature sediment samples whose maturity can be hardly determined by vitrinite reflectance. However, correlations between thermal alteration of the fluorescent substances and the "red-shift" in the spectra are not clarified well. In this investigation, we examined thermal alteration of fluorescence spectra and chemical structures of fluorescent substances in the resinite from Latrobe Valley (Victoria, Australia). The samples were heated stepwise from 100℃ to 320℃ at 20℃ intervals for 15min at each temprature. We observed fluorescence spectra and ultraviolet-visible (UV-VIS) absorption spectra of the samples cooled after maintaining for 15min at each temperature. The "red-shift" in the fluorescence spectra was associated with alterations of UV-VIS absorptions. The IR spectra of the original samples and of the samples obtained after heating at the final temperature were also determined. No IR absorption bands due to aromatic rings appeared after the heating. These facts indicated that elongations of conjugated double bonds caused the "red-shift" of fluorescence.