Geochemical study of alternating beds of chert and limestone in the Sambosa Terrain, western Shikoku

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Authors:Ohashi, Masayoshi
Author Affiliations:Primary:
Nagoya Univ., Dep. Earth Sci., Nagoya, Japan
Volume Title:Chishitsugaku Zasshi Journal of the Geological Society of Japan
Source:Chishitsugaku Zasshi = Journal of the Geological Society of Japan, 90(10), p.733-753. Publisher: Nippon Chishitsugaku Gakkai, Tokyo, Japan. ISSN: 0016-7630
Publication Date:1984
Note:In Japanese with English summary. 49 refs.; illus. incl. 2 tables, 2 plates, strat. cols., geol. sketch maps
Summary:Some 21 cherts, 18 limestones, and 15 rocks intermediate in composition between the former two, were analysed for major and minor components. The rocks are interbedded with each other in the westernmost area of the Sanbosan terrain of Shikoku. The regression lines in the diagrams plotting respectively Al2O3 and TiO2 against SiO2 + CaCO3 run through the points for SiO2 + CaCO3 = 100% and Al2O3 or TiO2 = 0% and those for average shales. It is suggested that most rocks studied are mixtures of organic and/or chemical components represented by SiO2 + CaCO3 and the terrigenous clastic particles represented by Al2O3 and TiO2. Furthermore, the ratios MnO/Cr, Ni/Cr and Co/Cr are all low in the analysed cherts. It is inferred that the cherts would have been deposited not in pelagic but in a nearshore environment. Chemical analyses are all given in the appendices. [M.Ha.]
Subjects:Carbonate rocks; Chemical composition; Chemically precipitated rocks; Chert; Diagenesis; Geochemistry; Limestone; Nearshore environment; Sedimentary rocks; Sedimentation; Syngenesis; Trace elements; Asia; Far East; Japan; Environment; Sambosan Terrain; Western Shikoku
Abstract Numbers:86M/4728
Record ID:1985040273
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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