Tectonic position of the gold mineralization of the Karabash Mountain (Southern Urals): Examination of small structural forms

Abstract

Accorting to examination of the small structural forms and rotation shapes a new geotectonic model of the Karabash massif’ formation which is located in a zone of the Main Uralian Fault is considered. The clockwise torsion, steep incline axis to the North-East, cracking and several other features are explained by the conditions of tectonic crustal-mantle flow’s rising in a regional zone of a right shift. Eastern block was active. Conditions of decompression and warm-up caused avtometamorfizm and antigoritisation of ultrabasite. A rapid pressure collapse in the upper horizons of a crust was accompanied by a formation of the large steep echelon-like stretching cracks sub-parallel the sides of a shear zone in which metamorphic fluids were thrown off. As a result of sintectonic hydrothermal mineralization the stretching cracks filled by diopside, chlorite, garnet, carbonates and other minerals which formed the rodingite-like metasomatic rocks. Early rodingites were also subjected to deformation in a right shift zone (cataclasis, boudinage, rotational deformation) with simultaneous filling of cracks by the new generations of above-mentioned minerals. As a result of this deformations in the rodingite veins were formed the especially intensive cataclasis pillar-like zones. These zones have a steep fall to the NE and contain the richest gold ore. Following an interpretation of a satellite imagery there are three gently dipping (about 35°NE) of tectonic fractures cutting of the Karabash massif are distinguished. It is suggested that these fractures are the large torsion cracks which cut the the southern flank of a field. With a taking in a mind of rotation direction a lower part of the southern flank of a gold deposit could be located further to the east.