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| Titel |
Rheological behavior of glaucophane and lawsonite in experimentally deformed blueschists |
| VerfasserIn |
Daeyeong Kim, Ikuo Katayama, Simon Wallis, Katsuyoshi Michibayashi, Akira Miyake, Yusuke Seto, Shintaro Azuma |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124204
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| Publikation (Nr.) |
 EGU/EGU2016-3594.pdf |
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| Zusammenfassung |
| We performed a series of simple-shear deformation experiments on blueschist at 400–500°C and 1–2.5 GPa. Microstructures of samples deformed at 1–2 GPa are brittle, while they deformed at 2.5 GPa display ductile features. J-indices of glaucophane CPOs systematically decrease by increasing shear strain and confining pressure, and the angle to the shear direction is similar to that of a strain ellipsoid. These results, together with the variable orientations of recrystallized fine grains in a SAED image at 2 GPa, suggest that the brittle-ductile transition of glaucophane occurs at ~2 GPa. On the other hand, lawsonite shows abundant fractures in the most specimens and a poor correlation among the J-index, shear strain, and confining pressure. The results demonstrate the predominant role of glaucophane on rheology of blueschist rather than lawsonite. Considering a strong fabric in the starting material and dry experimental condition, the brittle-ductile transition of glaucophane could occur at much shallower pressure than 2 GPa. Therefore our results indicate the dehydration embrittlement of subducting oceanic crust as an important factor in the origin of intermediate-depth earthquakes. |
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