New data on the study of deformation structures of the Lower-Yana overthrust and the eastern flank of the Lower-Yana Au-Sb-Hg metallogenic zone are presented. The overthrust is manifested by melanged, shattered, dislensed debris of local rocks with chaotic blocks and rounded boulders of xenogenic carbonate formations with traces of large-scale movements. Heterochronous fold-thrust, strike slip and normal faults parageneses related with Mesozoic-Cenozoic regional tectonic processes are described. The Lower-Yana overthrust and poorly permeable Jurassic clastic rocks of allochthon served as a screen for trans-crustal Au-Sb-Hg ore-forming fluids ascending along the Yana fault zone.

The results of structural-kinematic studies of the Marinskoe orogenic gold deposit in the Allakh-Yun metallogenic zone (Southern Verkhoyansk) are presented. The deposit is localized in the asymmetric anticlinal fold hinge disrupted by longitudinal faults. Late-orogenic brittle ore-controlling structures are superimposed on early-orogenic brittle-plastic deformations, which may indicate the exhumation of the latter before ore formation. Three differently oriented systems of gold-bearing vein-veinlet bodies formed in the thrust-fault stress field are identified. 40Ar/39Ar age of the sericite from the transverse quartz-carbonate vein was 119.4±4.7 Ma. This dating corresponds to the time of formation of large granitoid massifs and late orogenic gold deposits of the Allakh-Yun zone associated with asthenospheric upwelling in the rear of the active continental margin.

The Badran orogenic gold deposit is located in the Yana-Kolyma belt, Eastern Siberia, it has proven reserves of ~9.3 t of gold and an average grade of 7.8 g/t. The total gold production at the Badran deposit since 1984 amounted to ~ 34 t. Despite many years of study, the origin of the gold deposits of the Yana-Kolyma metallogenic belt one of the world's largest belts, and the Badran deposit is controversial. Synthesis of regional geology, geology and structure of the Badran deposit, fluid inclusion analysis, mineral and (S-O) isotope chemistry defines the genetic model, origin of fluids and source of metals in the evolution of the ore-forming system, equivalent to other orogenic gold deposits on the margin of the Siberian craton. The deposit is localized in the Upper Triassic clastic rocks and is controlled by the NW-trending thrust. The ore bodies of the deposit are controlled by the Nadvigovaya zone; the formation of ore bodies is associated with Late Jurassic-Early Cretaceous deformations by reverse-thrust kinematics, which was the transit path of trunk fluids. The calculated position of the paleotectonic stress fields of the ore stage is as follows: σ1 - 46/60, σ2 - 315/2, σ3 - 225/28. Polyphase mineralization occurs as disseminated arsenian pyrite and arsenopyrite ores with invisible gold, quartz veins with native gold and Fe, Pb, Zn, Cu sulfides and sulfosalts of orogenic type, and locally post-ore Ag, Sb-bearing minerals and Hg epithermal features. The quartz veins with native gold were formed from a boiling low-medium saline (1.5-10 wt% NaCl eq.) aqueous-carbonic fluids at temperatures of 290 to 210 °C and pressures of 300-250 to 125 bar. δ34S values of pyrite and arsenopyrite vary from -1.1‰ to +2.4‰, with an average of +0.4‰; the δ18О of quartz from +15.1‰ to +17.5‰ at constant d18ОH2O about +7.5 ‰ (± 1.0‰). High contents of As (up to 2.4 wt%), Co/Ni ~ from 0.3 to 9.9 in pyrite of proximal alteration, are typical for hydrothermal systems. The results obtained confirm that the ore-forming fluids did not have a single origin, but were formed from a mixture of subcontinental lithospheric mantle and metamorphic sources. The subcrustal lithospheric mantle was fertilized in the time preceding mineralization (Late Jurassic) and was derived directly from the down-going subduction slab and overlying sediment wedge at the closure of the Oymyakon Ocean.

The results of the geochemical analysis of near-ore metasomatites and ore zones of the Kuchus Au-Sb-Hg deposit are presented. The analysis of the concentration of the main (rock-forming) elements in near-ore metasomatites and the nature of their migration indicate a large-scale occurrence of low-temperature acid metasomatosis in the studied strata. Rare elements are divided into 4 groups by the nature of migration in metasomatites and ore zones and presence of correlation relationship and formation of aureoles. The distribution of the elements of a productive association is laterally zonal.

On the example of gold-ore deposits of East Yakutia a micro-structural analyses of enclosing rocks have been made. The techniques of analyses and classifications have been considered which helped to determine micro structural paragenesis and to define the level and a character of deformation. Besides, it was established that a morphology of ore bodies depended on the type of deformation.