1994 Fiscal Year Final Research Report Summary
Significance of hydrocarbons in anorthite megacrysts from island arc.
| Project/Area Number |
05453004
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | University of Tsukuba |
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Principal Investigator |
KIMATA Mitsuyoshi Institute of Geoseience, University of Tsukuba Assistant Professor, 地球科学系, 講師 (20143167)
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| Co-Investigator(Kenkyū-buntansha) |
ARAKAWA Yoji Department of Geology Faculty of Education Saitama University, 教育学部, 助教授 (00192469)
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| Project Period (FY) |
1993 – 1994
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| Keywords | anorthite / megacryst / olivine / garnet / inclusion / native copper / island arc / magma |
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| Research Abstract |
Hydrocarbons, verified by high-temperature Micro-FTIR,are found to be included by the same anorthite and labradorite megacrysts containing native coppers, as described in Part 1, in basaltic rocks, from Japanese island arc and in the westem continental margin of North America, respectively. A finding of Muntz metal (Cu_<60> Zn_<40> ) within the anorthite megacryst offerred the establishment of Hume-Rothery's rule in nature. Concerning the genesis of native coppers coexistent with the hydrocarbon, the exsolution model fortified by their purity and oriented distribution has been suggested and can account for crystal growth of native coppers based on the theory of Ostwald ripening. While continental margins and lsland arcs have geological and tectonical backgrounds common to each other, remarkable difference in morphology between fractured labradorites and euhedral anorthites seems to flare up in the power of the volcanic eruption. Moreover it proved that the corroded olivines within anorthite megacrysts hereupon have also a trace amount of hydrocarbons, detection of which discloses that the magmas crystallizing these anorthite and olivines contained the same hydrocarbons. Fe/Mg ratio of the corroded olivines, Sr-content and Sr-isotope ratio of anorthite megacrysts typical of arc-volcanism in Japan afford the lateral variations from the Japan trench to the Back arc side, and their geochemical behavior witnesses the rapid crystallization of anorthite megacrysts and their corroded olivines in close association with the crust components and the slabsediments subducted beneath the island arc.
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[Publications] Kimata, M., Nishida, N., Shimizu, M., Saito, S.and Arakawa, Y.: "Paragenesis within anorthite megacrysts as a proxy for past changes in the basaltic arc-magma" NATO ADVANCBD STUDY INSTITUTE,Feldspars and their Reactions, Bdingburgh, UK.Poster. 5. (1993)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Kimata, M., Nishida, N., Shimizu, M., Saito, S., Matsui, T.and Arakawa, Y.: "Anorthite megacrysts from island arc basalts.Mineral.Mag., Feldspar" volume, 59(394). 1-13 (1995)
Description
「研究成果報告書概要(欧文)」より
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