| Project/Area Number |
09440177
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Okayama University of Science |
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Principal Investigator |
ITAYA Tetsumaru Okayama University of Science, Research Institute of Natural Sciences, Professor, 自然科学研究所, 教授 (60148682)
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| Co-Investigator(Kenkyū-buntansha) |
HYODO Hironobu Okayama University of Science, Research Institute of Natural Sciences, Lecturer, 自然科学研究所, 講師 (50218749)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥11,400,000 (Direct Cost: ¥11,400,000)
Fiscal Year 1998: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1997: ¥9,000,000 (Direct Cost: ¥9,000,000)
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| Keywords | Quarternary / volcanic rock / historical lava / K-Ar age / unusual argon isotopic ratio / mass fractionation / HP-VEE / laser heating / 第四記 / 単結晶 |
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| Research Abstract |
This study is to analyze noble gase isotopes such as mainly argon extracted from extremely small amount of groundmass and phenocrysts separated from young volcanic rocks. To perfome it, We have purchased an laser probe heating apparatus and then carried out the basic experiments using it and the high precision incremental heating device with the temperature control system.
We have collected volcanic rocks including historical lavas systematicaly from Asama, Akagi, Miyakejima, Sakurajima, Satsuma-lwojima, Miharayama (lzu Ohshima) and Kyushu-Aso which have been documented well for their volcano stratigraphy. The rocks were studied petrographically and their groundmass and phenocrysts were separated for K-Ar analyses. Groundmass and phenocrysts were analysed using single grains or crystals. The results show that the analytical errors were ca. 40% for ^<40>Ar/^<36>Ar ratio and higher than 50% for ^<38>Ar/^<36>Ar one due to extremely small amount of argon content. In bulk groundmass analysis of the rocks using the resistance furnace, a mass fractionation for argon isotopes were detected because of small error less than 1%.
We reformed completely the former gas extraction and purification line and then performed a computer systems controlling automatically the signal detection and valve control. HP-VEE processing on Windows was used for the programming. The newly constracted extraction and purification lines were controlled using the system. The program for argon analysis using the peak height comparison method was also developed. All the analytical works are done on a computer. This unique analytical system using HP-VEE program will be reported somewhere soon. The base to proceed this research program was completed although K-Ar dating of rocks was not carried out. K-Ar dating result of rocks using the former mass spectormeter has been published in part.
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