The article proposes a genetic geological model of diamond deposit formation associated with kimberlites and lamproites. It is based on the synthesis of published data on diamond-bearing kimberlite systems and an original study of the ontogenetic features of diamond crystals. Deep diamond crystallization, its upward transportation and subsequent concentration in near-surface kimberlite-lamproite bodies and other rocks, including those brought to the surface by high-amplitude uplifts of crystalline basement rocks, are combined in a single system. An assumption is made about the primary sources of the Anabar placer diamonds. The possibility of hydrocarbon generation at mantle levels corresponding to diamond formation areas and their transportation to the upper crustal zones by a mechanism similar to the mantle-crust migration of diamond-bearing fluidized magmas is shown. The high rate of their upward movement allows transportation to the surface without significant loss as a result of dissolution in melts and sorption on the surface of mineral phases. The significant role of fluid dynamics at all stages of this system is noted.
The Nora area located in the Dzhagdy-Selemdshinsky metallogenic zone (the eastern part of the Mongol-Okhotsk fold belt) is poorly explored but there is an evident prospect for discov-ering a hard-rock gold deposit. Based on the common Mongol-Okhotsk fold belt strike and the previous exploration results, the recent prospecting works were focused upon revealing ore-bodies of the east-west strike. Analysis of their data has drown the conclusion that there might be at least two stages of gold-bearing mineralization at the explored area. The first one - Au -Ag-As-W stage is typical for deposits in the Dzhagdy -Selemdshinsky zone. It occurs mostly in ore-bodies of the east-west strike. The second – later stage, with the Au-(Ag)-Pb-(Zn) association, has been for the first time detected at this area. It is controlled by latent fractured structures of the north-south strike. Maximum gold concentration is characteristic for ore-bodies with combined development of both stages. Revealed regularities in location of various types gold-bearing mineralization should be taken into consideration for the grid of prospecting works and confirm the high potential of the Nora area.
Peculiarities in distribution of concentrations and mass shares of gold in its ores in recoverable gold deposits should be considered as indicators of the genetic nature of gold mineralization. Practical application of the revealed distribution allows the new estimating of the nature of those gold concentrations.
On the base of typomorphic peculiarities of gold from placers and primary occurrences there are made conclusions about multistage and polytypic character of gold mineralization at the area, with some assumptions for belonging of gold occurrences to certain ore formation types. These data may be used as guidance for prospecting expansion.
