1992 Fiscal Year Final Research Report Summary
PHEOLOGY OF SOLID MATERIALS OF DEEP EARTH'S INTERIOR
| Project/Area Number |
03302024
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| Research Category |
Grant-in-Aid for Co-operative 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 | UNIVERSITY OF TOKYO |
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Principal Investigator |
TORIUMI Mitsuhiro University of Tokyo,Faculty of Science,Professor, 理学部, 教授 (10013757)
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| Co-Investigator(Kenkyū-buntansha) |
KITAMURA Masao Kyoto University Faculty of Science,Associate Professor, 理学部, 助教授 (70004489)
TAKESHITA Toru Ehime University,Faculty of Science,Associate Professor, 理学部, 助教授 (30216882)
FUJII Toshitugu University of Tokyo,Earthquake Research Institute,Professor, 地震研究所, 教授 (00092320)
SHIMAMOTO Toshihiko University of Tokyo,Earthquaki Research Institute,Associate Professor, 地震研究所, 助教授 (20112170)
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| Project Period (FY) |
1991 – 1992
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| Keywords | rheology / high pressure minerals / dislocation / parallel computer / garnet / brittle-ductile transition / molecular dynamics / flow law |
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| Research Abstract |
Main theme of this group research on rheology of the Earth's interior are focused on studying physical mechanisms of plastic and brittle deformation of minerals and rocks. Since 1970,rheology of planetary and Earth's materials has been investigated experimentally. Recent precise experiments on this subject began to perform from 1978 at MIT,ANU,UCSA and UT(Karato and Toriumi). Furthermore,in the brittle field frictional slip behavior were determined exactly by Texas AM(Logan and Shimamoto). Shimamoto(1986) proposed shear instability in the brittle-ductile transition regime. After these experimental investigations,hot discussions proposed are summarized as follows;rheology of ultrahigh pressure minerals,pressure-dependence of flow law,hydrolytic weakening of minerals, Plastic and frictional instability,constituitive law of materials in the brittle-ductile transition regime, rheology of polyphase and polycrystallinc aggregates.
In the study of this grant-in-aid we conducted deformation mec
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hanisms of ultrahigh pressure minerals such as garnet and make a simulator of molecular dynamics dislocation motion and computer simulation of polyphase and polycrystalline aggregates. By this investigations introduction of crystal dislocation requires for very long cpu times of very fast super computer. For examples,1000 particles MD simulations need 12.5 seconds per 1 step even by 100 Mflops(double)cpu. Thus,we made a new type special backend computer equiped on microcomputer which is composed of parallel-connected 5(6) transputers(T800 of INMOS,England). The ability of this backend parallel computer is about 10 Mflops and 100 Mips. Language for simulation is parallel fortran of 3L company. This backend machine can be applied to simulate the polyphase flow.
Rheology of garnet is quite important to infer the nature of transition layer of upper and lower mantle. We proposed very hard rhcology of garnet due to very slow velocity coming from expanded dislocations in garnet which were assigned by TEM. Garentite formed under 10-16GPa and 1600 C indicated a great contrast of rhcology between small amount of pyroxene and stishovite,and majority garnet.
To get a natural data derived from many studies of lower crust metamorphism and tectonics of subduction and collision zones,we convened the workshop of Precise determination of P T t paths of metamorphic rocks involving deformation and reaction at Matsue. The workshop was very excited and successful. It is clarified that reaction and deformation is interlocked with each other. Less
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