1988 Fiscal Year Final Research Report Summary
A study of microstructure and texture of minerals to estimate the condition of formation
| Project/Area Number |
60420017
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
鉱物学(含岩石・鉱床学)
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| Research Institution | Osaka City University |
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Principal Investigator |
AIKAWA Nobuyuki Faculty of Science, Osaka City University, 理学部, 助教授 (20047327)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Takeshi Faculty of Science, Osaka City University, 名誉教授 (60046761)
YOSHIDA Masaru Faculty of Science, Osaka City University, 理学部, 助教授 (30047112)
FURUYAMA Katsuhiko Faculty of science, Osaka City University, 理学部, 助手 (10112525)
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| Project Period (FY) |
1985 – 1988
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| Keywords | Cation distribution of minerals / Temperature and pressure dependence of cation distribution / Deformation structure of quartz and calcite / Lattice microstrain of quartz and calcite / 石英 / 方解石の変形構造 / 石英・方解石の格子歪 / 地質体の熱 / 応力履歴 |
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| Research Abstract |
1). X-ray study of cation distribution of silicate minerals The cation distribution of natural and heat-treated specimens was examined by X-ray diffraction method. The distribution constants, Kd=(M^<+2>M1/(M^<+2>/Mg); M^<+2>=Fe, Mn, of natural samples range from 0.8 to 1.25 for Fe-Mg olivines and from 0.05 to 0.1 for Mn-Mg tephroites, and those of heat-treated specimens were more than 1.15 for Fe-Mg olivines and more than 0.3 for tephroites. The change of Kd was observed on specimenswhich were heated for a short period of time. Thus the rate of reordering reaction is very fast process. On the basis of the change of the lattice parameters due to the difference of Kd, the overall effect on the unit cell volume is a decrease with the increasing Kd, suggesting the presence of the significant pressure dependence of the cation distribution. These results may be applied the cooling history of the geologic body, and are important to understand the physical properties of olivine under pressure.
2). Deformation and recrystalization textures of quartz and calcite. It has been definitely shown by the X-ray line braodening analysis that the relationship between lattice microstrain and dislocation density of naturally deformed quartz in metachert and granitic rock could be applied to estimate the stress level at the tectonic movements. The rate of the grain bundary diffusion and the activation energy for diffusion were estimated by the study of grain growth process of microcrystalline quartz in contact aureole. The activation energy for recovery of deformed calcite was also estimated by the heating experiments under the controlled atomosphere. These results enable us to estimate the thermal history of geologic body.
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