The nature of potassium feldspar, exsolution microtextures and development of dislocations as a function of composition in perthitic alkali feldspars

摘要: Transmission electron microscope data on the morphology of exsolution lamellae, nature potassium feldspar and development dislocations at lamellar interfaces in coherent cryptoperthites fine microperthites are reviewed. Dislocations have been reported previously only two crystals, periodic noted one, an Or-rich microperthite. Periodic (spacing 100–150 nm) here described from a ternary mesoperthite (Or26 Ab52 An22). Small crystallites (<30 other phases sometimes nucleated dislocations. The 020 lattice fringes imaged; difference spacings can be almost entirely accommodated by regular dislocations, so that boundaries may termed nearlyperfectly semicoherent.