The history of tectonic development and granitoid magmatism of Northeast Asia in the late Mesozoic is considered. The variety of tectonic situations and granitoid magmatism are favorable circumstances for the solution of many fundamental problems in geology, but tectono-magmatic division into districts is complicated owing to variability of the composition and the structure of the Earth’s crust. A rational approach to the tectonic division into districts of a region by the research of granitoid magmatism based on determining consolidated crust blocks with various tectonic history is offered. Pre-mesozoic and mesozoic structures of the Far East, among which primary and superimposed on the Precambrian and Paleozoic base Verkhoyansk orogeny prevails, are determined. The conclusion on the important role of middle massifs and passive margins with a thin Riphean-Paleozoic cover in geodynamic development of the Far East is drawn. The mesozoic activization of ancient structures along with young granitoid magmatism is established. The driving force of the Pacific ore belt granitization was the interaction of the Paleo-Pacific Plate and plates in Northeast Asia in the middle-late Mesozoic. The history of regional tectogenesis and granitoid magmatism in the late Triassic – Eocene (230-33,7 million years) taking into account the latest geodynamic concepts is tracked. The place in tectonic history of the Asian continental margin of plutonic and volcanic-plutonic belts is determined. Four stages of tectono-magmatic development of the Far East are established: the Jurassic and the early Cretaceous collisional, the early Cretaceous upsubduction, the late Cretaceous upsubduction-transform and the late Cretaceous – Paleogene rift-related. The directed constructive evolution of the Earth’s crust of the Far East is established: origin and building of ancient cratons on margins of the continental crust sated with granitoid intrusions, increase of a silica acidity and alkalinity of the granitoid magmas and formation of late Cretaceous ore-bearing lithium-fluoric granites at the final stage.
Taking into consideration published and author's data, occurrence of areas of rare-metal granitic magmatism in Central and East Asia is investigated. The Far East Belt of lithium-fluoric granites and ongonites is defined. Reasons and history of development of rare-metal granitic belts in North-east Asia are discussed. The conclusion that the Far East Belt of lithium-fluoric granites controls the largest tungstentin fields of the Far East is drawn.
The main lines of monazite-(Ce) and xenotime-(Y) composition evolution were established in granitoids of the Verkhneurmiysky massif in Amur River region. It is suggested to use revealed features of accessory phosphates composition for a regional partition of granitoids and the assessment of intrusive massifs orepotential.
Zwitters are metasomatic rocks associated with rare-metal granites. Petrological, geochemical and mineralogical features of zwitters are given. For dark micas features of chemical composition and type of structure is described. Geochemical specialization of metasomatic solutions is characterized. Data about accessory minerals are given.
In terms of current research, the methodological comparison of the evolutional crystal morphological analysis and the thermodynamic approach to the zircon thermometry was carried out. The complex application of the both methods is the most appropriate to assess the thermal evolution of the granites. The main features of the thermal evolution in granites of the Verkhneurmiysky massif were revealed. The obtained trends of the thermal evolution confirms the existing conception of the geological evolution of the Badzhalskaya volcanic zone.
Having used electron microscopy permits and microanalysis systems for monitoring the general chemical composition of the sample researched forms of occurrence of toxic elements in the granitoids one of regions. As a result, studies have established stable and unstable forms of occurrence of toxic elements. Concluded that secondary hydrothermal forms of concentration of toxic elements may constitute an environmental hazard. Two cycle scheme proposed geoecological monitoring, providing samples of sediment and flowing waters of the river basins.
In the Mesozoic history of the volcano-plutonic magmatism of Badzhalsky area the fourth Late Cretaceous ongonitic stage is specified. The ongonitic magmatism of the Amur River region was evolving during several hundreds of thousand years, had cellular nature and eventuated in the zinnwaldite-microcline-albite granitoids formation with rare-metal accessory complex. In the near-contact zone of the Verhneurmiysky massif Pravourmiysky ongonitic complex, which controls the biggest tungsten-stanniferous deposits of the area and includes ongonite dykes and rare-metal granites of the Dozhdlivy intrusive dome, is determined.
Having used electron microscopy permits and microanalysis systems researched typomorphic features of the zircons from Verchneurmijsky granite massif in Priamurye. Crosscutting study of the zircon crystal morphology and ultimate composition to predict peculiar properties of mineragenesis conditions and afford opportunity to draw sharp disjunction of zircon features from different intrusive phases. Features of the zircons can be used at regional partition of intrusive formations and searches of rare-metal granites.
Having used an optical and raster electronic microscopy were analyzed a topaz granites with accompanying them ongonites discovered for the first time in Chaunsky area of Chukotka. Finding history, specifics of geological location, mineral composition and rock structure are described. Their connection with stannane orebody is considered. The topaz granites have essentially albite composition, contain zinnwaldite, topaz, fluorite and first located in Far East granites wolframoixiolite. The pyrkakajsky intrusive complex of rare-metal granites is allocated. A conclusion about the development possibility of Chaunsky rare-metal deposits potentials is drawn.
The Kamentsev I.E. and Sorokin N.D. method is used to investigate the dependence of Al-Si-ordering and structure of alkaline feldspars decomposition in different granites from the Severny massif (Chukotka) under thermobaric conditions of their crystallization. The temperature and pressure on the granite system in the initial period of feldspars ordering are determined quantitatively for the first time for the region. Progressive pressure change which exceeds lithostatic load by 750 МPа at the late stage of lithium-fluoride granites formation is revealed. It is hypothesized that the deposits similar to explosive ore-bearing breccia can be discovered in the Chukotka. The conclusion on possibility to apply the Sobolev-Dobretsov concept of superpressure to interpret the process of rare-metal magmatism is drawn.
