Abstract: Through particular thin section observation and stress-strain analysis on gabbro, granulite and plagioclase amphibolite samples studied by high temperature and high pressure deformation experiment, a conjugate fan structure model, which was proved reasonable, was set up. Two kinds of orientational fabrics, one being compressional stretching orientation, the other shearing orientation, were distinguished out of at the same time. With identification of the major deformation minerals and deformation fabrics, the deformation structure and deformation mechanism of three typical rocks, gabbro, granulite and plagioclase amphibolite from middle-lower crust level were described particularly, such as the dispersing band structure of gabbro sample and conjugate fan structure of granulite and plagioclase amphibolite samples. Conclusions of the paper include: (1)In the middle-lower crust, the deformation of lithosphere is mainly concentrated on one or several components which can flow most easily. (2)With the concentration of deformation, certain component can also concentrates. (3)Deformation is not only the important factor to control the physical or chemical condition of deep inhomogenous lithosphere, but also the important controls to form deposit.

Key words: melt, middle-lower crustal rocks, deformation, structure