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ID 117523
タイトル別表記
Extracting-method of pyrite micrograins as an indicator for mudstone weathering
著者
佐藤, 威臣 国土防災技術
竹熊, 隆宏 国土防災技術
長谷川, 修一 香川大学
キーワード
mudstone weathering
slaking
framboidal pyrite
oxidation
hydroxidation
extracting methodology
HF-processing
biomineralization
oxygen minimum zone
anoxic event
Cretaceous
Fujikawa Shale
Monobegawa Group
non-accreted formation
Kurosegawa Terrane
environmental geology
資料タイプ
紀要論文
抄録
Applying to the indicator of mudstone weathering, an extracting method of pyrite micrograins and the secondary materials formed by oxidation and hydroxidation was examined using water diluted HF (3%). Based on the condition of extracted materials, the weathering grade of the drilling-cores of the Lower Cretaceous Fujikawa Shale Formation was subdivided into Oxidized- (weathered), Fresh-Oxidized Coexistence-, and Fresh- (non-weathered) zones in the order from the ground surface. The Fresh Zone is identified by only occurrence of non-altered primary pyrite micrograins that originate a bio-chemical process in sedimentary stage, and are characterized by aggregation of framboidal (raspberry-like), tubal (pellet-like), cubic and dodecahedral shapes. In the Fresh-Oxidized Coexistence Zone, pyrite micrograins and the secondary materials (hematite, goethite and limonitic hydrous ferric oxides) formed by oxidation and hydroxidation of pyrite co-exist, whereas the Oxidized Zone is characterized by the occurrence of ferric secondary materials without primary pyrites. A pyrite-alternation model was proposed in relation with the progressing of slaking. The Extracting-method of pyrite micrograins is useful even the case that the pyrite peak is not detected by X-ray analysis because of lower containing percentage.
掲載誌名
自然科学研究
ISSN
09146385
cat書誌ID
AN10065859
出版者
徳島大学総合科学部
20
開始ページ
25
終了ページ
33
並び順
25
発行日
2006-12-22
EDB ID
フルテキストファイル
言語
jpn
著者版フラグ
出版社版
部局
理工学系