Tevelev, Al. V., Kosheleva, I. A., Tevelev, Arc. V., Okhapina, E. Y.
The Boundary Zones of the Eastern Urals
Natural restrictions of the East Uralian structures are two intensive deformed boundary zones, which are the Sheludivy Gory Boundary Zone (SGBZ) in the west and the Redutovo Boundary Zone (RBZ) in the east. SGBZ represents a package lens-shaped and steeply dipping faulted blocks, horizontal dimension of which usually does not exceed 2 km. Thin linear serpentinite bodies are found some times between the slices of various origin and composition, and different in age. Along the whole length, SGBZ is saturated by numerous quartz veins and other hydrothermalites with gold-ore occurrences. Rocks within the SGBZ shows extremely uneven tectonization, complementary faults are often accompanied by small vertical (strike-slip-related) and recumbent folds. We suggest that observed structure of the SGBZ has been formed in transpressive setting during the late Kimmerian orogeny.
The Redutovo boundary zone inherits a Triassic rift basin, and has a width near 5 km at the length more than 80 km. RBZ is composed also of a package of the steeply dipping faulted blocks with horizontal dimensions less then 2 km. The rocks of these slices are the Ordovician siliceous shales and basalts (similar to formations of SGBZ)), the lower Carboniferous volcanics and carbonates, late Paleozoic granites, and the Triassic basalts and coal-bearing clastics. Like SGBZ, this zone is also saturated by numerous quartz and other veins with gold-ore occurrences. Deformation degree in this boundary zone are significantly higher than in the former. Recent geometry of the Cheliabinsky Graben remnants allow to suggest that closure of this rift zone took place under transpressive arrangement resulted from motions in N-S convergent dextral strike-slip fault zone. Intensity of deformation strongly increases nearby the faults separated the different tectonic blocks.
The work is supported by RFFI, grants 96-05-65519, 96-05-65521.