40ar/39ar Age of Gold-Quartz Ores and the Relationship of Plastic and Brittle Deformations at the Marinskoe Deposit of the Allakh-Yun Metallogenic Zone (Southern Verkhoyansk)

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.