1996 Fiscal Year Final Research Report Summary
Evolution of the Hida metamorphic rocks from the view point of clinopyroxene mineralogy
| Project/Area Number |
06640613
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Toyama University |
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Principal Investigator |
SOHMA Tsuneo Toyama Univ. Faculty of Education, Professor, 教育学部, 教授 (40019039)
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| Co-Investigator(Kenkyū-buntansha) |
GOTO Atsushi Himeji Institute of Technology, Faculty of Science, Research Assistant, 理学部, 助手 (50211917)
KUNUGIZA Keitaro Toyama Univ. Faculty of Education, Associate Professor, 教育学部, 助教授 (30225180)
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| Project Period (FY) |
1994 – 1996
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| Keywords | Hida metamorphic belt / Clinopyroxene / Gneiss / Calc silicate / Metasomatism / Skarn / Fluid phase / Mechanical mixing |
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| Research Abstract |
Evolution of the Hida metamorphic belt was discussed from the view point of clinopyroxene mineralogy. Followings are major conclusions.
1. Clinopyroxene gneiss of the Hida metamorphic belt was formed by mechanical mixing of metabasite and limestone, thereby the reaction tr+cc+qz=di+H2O+CO2 takes place. Inishi-type rocks include both the product of the mechanical mixing of the rocks and that of dyhydration melting of amphibolite.
2. Mechanical mixing of rocks is a major process of metasomatic reaction. This process results in the compositional change of system, and therefore metamorphic reactions due to the difference between the free energy of simple mixture of rocks and that of products take place. This type of metamorphic reactions is of non-isochemical reaction, being in contrast to a general view that metamorphic reactions take place in response to the change of temperature and pressure within isochemical system.
3. The concept of non-isochemical reaction extends to fluid bearing systems. We found that the metamorphic reactions by mechanical mixing of rocks results in the abrupt release and compositional change of fluid phases, and consequetly different reactions may occur.
4. Mechanical mixing of rocks leading to the non-isochemical metamorphic reactions is enhanced by accretionary process at the leading edge of continents, in other words, continental mobile belts. Since non-isochemical reactions are of irreversible processes, the petrological properties of continental mobile belts continue to be progressively chanced upon Wilson cycle.
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[Publications] Kunugiza, K., Kato, Y., Kano, T., Takaba, Y., Kuruma, I.and Sohma, T.: "An Archaean tectonic model of the Dharwar craton, S.India : the origin of the Holenarsipur greenstone belt (the Hussan district, Karnataka) and reinterpretation of the Sargur-Dharwar relationship" J.Southeast Asian Earth Sciences. 14. 149-160 (1996)
Description
「研究成果報告書概要(欧文)」より
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