On the origin of translation lamellae in olivine

Abstract

SummaryTranslation lamellae in olivine crystals are generally considered to be a result of mechanical deformation of pre-existing crystals but a recent hypothesis suggests that they may be formed during the latter stages of olivine crystallization in olivine-rich rocks due to the stresses imposed by mutual interference. Olivine crystals showing well-developed translation lamellae occur in the ultrabasic dykes of south-west Skye and it is demonstrated that these lamellae are unlikely to have been formed by mutual interference. Possible origins of the lamellae are considered and it is concluded that they are most likely to have been formed by tectonic deformation at elevated temperatures prior to the intrusion of the dykes.