- journal_title：European Journal of Mineralogy
- Contributor：Hosni Idrissi ; Patrick Cordier ; Damien Jacob ; Nicolas Walte
- Publisher：E. Schweizerbart'sche Verlagsbuchhandlung Science Publishers
- Date：2008-
- Format：text/html
- Language：en
- Identifier：10.1127/0935-1221/2008/0020-1849
- journal_abbrev：Eur J Mineral
- issn：0935-1221
- volume：20
- issue：4
- firstpage：665
- section：Other Articles
Dislocation microstructures have been characterized by transmission electron microscopy in polycrystalline coesite deformed experimentally at 4 GPa, 1200 °C. Burgers vectors have been determined by large-angle convergent-beam electron diffraction. Sample orientation was assisted by precession electron diffraction to overcome difficulties arising from pseudo-hexagonal symmetry. The results are explained by using a pseudo-hexagonal setting. We found that most dislocations observed are of the ⅓〈21̅1̅0〉 type. No clear glide plane was identified, suggesting that climb is activated under these conditions. This conclusion is supported by the observation of numerous subgrain boundaries. We have also observed some [0001] dislocations. Finally, the C12/c1 space group to which coesite belongs being centred, an additional slip system is observed: ⅙ [1̅21̅3] (011̅1) (½ [1̅10] (110) in the monoclinic setting).