Search

This work presents а structural interpretation of a well-known gold deposit from SW Bulgaria. The interpretation is based on the geological map and structural data, collected during the prospecting. The data indicates that а regional sinistral shearing was responsible for a low rank sinistral shear system, which created ore depositional space by the combined action of shear extension and compression. The two mechanisms opened tension gashes, dilated previously formed Riedel faults and buckled the veins and the faults. The buckling happened, when the structures were rotated anticlockwise in the compressional quadrant of the space between the regional shears thus creating buckling structures. Ore shoots have been formed in the extended domains of the main shear and along the dilated previously formed Riedel shears.

The structural geological features defining the discontinuity network in metamorphic rocks hosting railway tunnels are described. Discussion on the faults, joints, lineation and stresses found from fault population is presented. It is demonstrated that the formation of some brittle joints is related to the ductile stretching lineation. The geotechnical situation for the tunnel construction is complicated and requires reassessment of the design solutions in order to accommodate substantial lateral forces and prevent shear of the tubes.