Japan Geoscience Union Meeting 2016

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Poster

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-P75] The Transition of Mineral Composition by Weathering

*Hiroki Oka1 (1.Yokohama Science Frontier High School)

Keywords:weathering, thin sections, andesite, orthopyroxene, limonite, the weathering process

All kinds of rock are weathered in nature. Minerals in rock are changed into other minerals as time goes on. In this study, a process of weathering was presumed by observing minerals of olivine-bearing two-pyroxene andesite under a polarization microscope collected at Nagaotoge, Hakone. Some kind of reddish brown substance was in orthopyroxene. The substance turned out to be limonite derived from a main ingredient of orthopyroxene. In addition, a cross sectional diagram which shows a look of weathering with depth from a surface of the rock was made based on the observations of three thin sections. It is thought that the dissolution or formation of minerals is happening near the surface. However, the weathering process was not presumed enough because the number of thin sections was small.