KINEMATIC BEHAVIOR OF AN INTERFACE AND COMPETENCE CONTRAST - ANALOG MODELS WITH DIFFERENT DEGREES OF BONDING BETWEEN DEFORMABLE INCLUSIONS AND THEIR MATRIX

In a system composed of a ductile matrix with a particle included in i t, the deformation of the matrix, the displacement field, and the rota tion and the deformation of the block are related to the viscosity rat io between block and matrix and also to the degree of bonding between the matrix and the block. In this paper, belemnites from the Lower Lia s of the Alps provide a natural example of moderately deformed objects included in a slaty matrix. They are compared with analogue models ma de of paraffin, in which a long block of a more competent paraffin is included. Depending on the degree of bonding between matrix and object , the same block appears to be deformable or quite rigid. With a high degree of bonding, the strain refraction observed corresponds to the v iscosity ratio between the block and the matrix. When the degree of bo nding is weak, the block is quite undeformed, its rotation is great an d the deviation of the strain in the matrix is analogous to that obser ved around a fault. The kinematic conditions appear to have a greater effect on the finite strain than the viscosity ratio of the materials.