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Fig. 3. The most common models of the formation of the paragenesis of plumage fractures of the main fault (main discontinuity) in the shear zone on the example of right shear. A - scheme of formation of plumage fractures near the surface of the main discontinuity (Smirnov, 1976). B - scheme of secondary fracture formation according to W. Riedel (Riedel, 1929): Y - main shears, R and R' - conjugate Riedel chipping, P - secondary shears, T - detachments, φ - angle of internal friction, σ1 - axis of maximum compression, σ3 - axis of maximum extension. B - systems of echeloned structural elements formed in the shear fault zone during simple shearing (Hancock, 1985): Y - trunk shears, R and R' - conjugate Riedel shears, X, P - secondary shears, e - detachments, n - dumps, t - outbursts, f - folds, S1 - cleavage, σ1 - axis of maximum compression, σ3 - axis of maximum extension. D - paragenesis of shear cracks in the shear zone (Gzovsky, 1975): variants of stress state at shear angles 45° (a), < 45° (b), additional tensile (c) and compressive (d) environments; 1 - fault; 2 - spalling cracks; 3, 4 - spalling cracks with right (3) and left (4) shear kinematics; 5, 6 - orientation of tensile (5) and compressive (6) axes in the horizontal plane; 7, 8 - additional tensile (7) and compressive (8) environments. |