GEOLOGY 1 Lecture Notes - Lecture 14: Ionic Bonding, East Los Angeles College, Mass Transfer
Document Summary
3 main ductile deformation mechanisms/processes accommodating ductile flow: dissolution/solution transfer. Mass transfer of material via a hydrous medium: intracrystalline deformation/plasticity. Movement of lattice defects through a crystal by a combination of glide (+/- diffusion) - dislocation creep: diffusional flow. Movement of lattice defects by grain boundary or volume diffusion - diffusion creep. Crystal lattice: 3d repetitive array of atoms/ions/molecules. Any mineral"s basic structure reflects the equilibrium configuration of its atoms/ions/molecules. Force which hold the lattice together is bonding. Ionic bonds: atom loses electrons to adjacent atom. Metallic bonds: weakly attached electrons which move freely through lattice. Increasing shear ductility and creep potential -> decreasing in strength. Strength of covalent bonding > ionic > metallic. If ideal crystal (lattice has no defects / flaws) Hydrostatic stress applied = elastic compression or elastic tension (recoverable dilation) Eventual tensile failure (rupture) occurs if tensile stress exceeds tensile strength (yield strength of bonds) Crystal fractures (cleaves) along plane or irregular breakage.
