Contribution
Dislocations in meteoritic and synthetic majorite garnets
Voegelé, Violaine; Cordier, Patrick; Langenhorst, Falko; Heinemann, Stefan
European Journal of Mineralogy Volume 12 Number 4 (2000), p. 695 - 702
22 références bibliographiques
publié: Jul 17, 2000
manuscrit accepté: Feb 7, 2000
manuscrit reçu: Aug 17, 1999
Abstract
Abstract Shock veins in the Acfer 90072, L516 (S6) chondrite contain polycrysta1line fragments constituted of ringwoodite and rnajorite. The dislocation microstructures of the rnajorite crystals have been characterised by transmission electron microscopy and large-angle convergent-beam electron diffraction. Most of the dislocations fonn sub-grain boundaries organised in cells. Some free dislocations can be found in the cells. Dislocations with ½ and Burgers vectors have been characterised. These microstructures compare well with those observed in majorite synthesised from a glass in multi-anvil experiments. These observations suggest that the dislocation microstructures observed in both synthetic and meteoritic majorite result from imperfect growth
Mots-clefs
majorite • gamet • meteorite • shock veins • dislocation • TEM • LACBED