Japan Geoscience Union Meeting 2016

Presentation information


Symbol O (Public) » Public

[O-02] Poster presentations by senior high school students

Sun. May 22, 2016 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Tatsuhiko Hara(International Institute of Seismology and Earthquake Engineering, Building Research Institute), Miwa Kuri(International Research Institute of Disaster Science, Tohoku University), Keiko Konya(Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology), Hajime Naruse(Department of Geology and Mineralogy, Graduate School of Science, Kyoto University), Kou Yamada(Waseda University)

1:45 PM - 3:15 PM

[O02-P05] The pyritization of microfossils

*Yuka Sato1, Haruhi Imahashi1, Arisa Matukura1, Hitomi Saito1, Yoshimi Honda1 (1.Gunma Prefectural Ota girls' high school)

Keywords:microfossils, framboidal pyrite , sulfate-reducing bacteria

Foraminifera, diatoms, and micro-shellfish filled with or substituted by pyrite were found during sample preparations in the study of microfossils. The aggregations of minute raspberry-formed structure of pyrite were observed by the electron microscopy. A raspberry-formed pyrite, known as a framboidal pyrite, consists of a number of microcrystals. Diameters and average major axes of framboid and microcrystal respectively were measured and the results show the positive correlations. The results indicate that framboidal pyrite grows with growths of microcrystals. A pilot study about the formation of pyrite in the natural reductive environment was performed in the rice paddy filed. This study confirmed that pyrite is formed within nine months. The result indicates that fossils filled with or substituted by pyrite could be formed in the reductive environment where sulfate-reducing bacteria inhabit.