Structural analysis of the Siahkamar shear zone and relation of brittle fabrics with gold mineralization (south of Birjand, Hired)


1 Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran

2 Faculty of Science, Department of Geology, Tarbiat Modarres University, Tehran, Iran


Hired mining area is located in the East of Central Iran, NNE border of Lut zone and west of Sistan suture zone. North part of strike slip trending Nehbandan fault system - that controls all deformations of Sistan structural zone - changes toward west and enters Lut zone. The study area is located in the southern part of the above- mentioned structural curvature. In this area, the ENE-WSW trending structures such as Siahkamar shear zone contain the reverse component predominantly. Fault rocks in shear zones are composed of foliated and none-foliated cataclasites, breccias and fault gouges. Fabrics in breccias and none-foliated cataclasites are random. S-C structure in XZ plane sections of polished hand specimens and thin sections of foliated cataclasites reveals shear sense of their related shear zone. Microscopic and mesoscopic fabrics in cores of Siahkamar shear fault zone show high deformation intensity in the interior parts of fault zone that decrease to the margins. Gold mineralization grade is directly related to deformation intensity in brittle shear zones.


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