Cation ordering in omphacite and effect on deformation mechanism and lattice preferred orientation (LPO)

摘要: We present microstructural data and lattice preferred orientations (LPOs) of omphacites from a suite eclogites, the Adula/Cima Lunga nappe (Central Alps). Our work shows surprisingly strong correlation between measured LPO ordering state cations in omphacite. Estimates deformation temperature metamorphic petrology, together with omphacite compositions LPOs, determine field (ordering state), on phase diagram, into which each sample falls. LPOs dominated by L-type S-type signatures are developed samples that fall P2/n (ordered structure) C2/c (disordered structure), respectively. Dislocations b=1/2〈−110〉 or b=[001] observed transmission electron microscope (TEM) all samples. The former change perfect dislocation structure to partial P2/n. Any movement requires formation growth stacking fault. Furthermore, order pass an obstacle has constrict unit dislocation. energy form constriction is high due large separation width. Thus, activity hindered relative structure, balance two might give rise different LPOs.