The Earth has a number of differences from the planets of the Solar System and other star-planetary systems. These differences were acquired during its formation and geological history. In the early Chaotic eon occurred the accretion of the Earth, the separation of the primary substance of the Earth into a mantle and a nucleus, a satellite of the Earth - the Moon appeared. 4500 Ma ago in the Gadey aeon the geological history of the Earth began. At this time, the endogenous processes on the Earth were controlled to a great extent by meteorite-asteroid bombardments, which caused large-scale melting and differentiation of the upper shells of the Earth. In the magmatic chambers differentiation proceeded until the appearance of melts of granitoid composition. The continental crust of Gadey time was almost completely destroyed by meteoric bombardments, the last heavy bombardment occurred at the end of the Gadey aeon 4000-3900 Ma ago. The geological situation of the Gadey time can be judged only from the preserved zircons from the rocks of that epoch. In particular, their geochemical features indicate that the Earth has an atmosphere. The Gadey eon was replaced by the Archean one, from which the processes of self-organization began to predominate on the Earth. At this time, a crust composed of komatiite-basalt and tonalite-trondhjemite-granodiorite (TTG) series of rocks was formed. In its formation, the processes of sagduction (vertical growth of the crust) over the rising mantle plumes was played the leading role. At the same time the lower basaltic crust was bured in the mantle, eclogitized and melted, which led to the appearance of the sodium series of TTG rocks. At the end of the Archean 3.1-3.0 Ga tectonics of the cover (LID tectonics), which determined the style of the structure and development of the Archean crust, is replaced by the tectonics of small plates, which was later replaced by modern tectonics - the tectonics of plates combined with mantle plumes.

Murzinka massif is a sheet-like interformational body steeply deeping to the East with length about 6 km. Proterozoic metamorphic rocks of the predominantly granulite facies ( P = 5-6 kbar, T = 750-800°C) occur at the base of massif, and volcanic-sedimentary Silurian-Devonian rocks metamorphosed in the epidote-amphibolite facies - in the roof of it. Analyzes of rocks are made in the Institute of Geology and Geochemistry. A.N. Zavaritsky (Ekaterinburg, Russia) by standard methods. Petrogen elements were determined on the X-ray fluorescence spectrometers CPM-18, CPM-25, VRA-30 and the rare elements - on the ICP-MS mass spectrometer ELAN-9000 company Perkin Elmer. In the eastern direction the rocks lying in the base of the massif change their composition from predominantly basic to granitic. The gneisses of granitoid composition underwent a high degree of melting, and theirs anatectic melt formed the western part of Murzinka massif. The granites form three complexes: yuzhakovsk - vein of biotite orthoclase antiperthite granites, varying in K₂O content, in the metamorphic rocks of the base of the massif, the vatikha - biotite orthoclase antiperthite granites in western part of the murzinka massif, and the murzinka s.s. - two-mica predominantly microcline granites in the eastern part of the massif. Vatikha and murzinka granites have the same isotopic age (about 255 Ma). A clear geochemical zonation is revealed in the massif: from the west to the east (from the base to the roof), the contents of Rb, Li, Nb, Ta grow in the granites of the vatikha and murzinka complexes. In the same direction, the ratios K/Rb, Zr/Hf, Nb/Ta decrease, as well as the content of Ba and Sr. Accordingly, the compositions of such rock-forming minerals as plagioclase and biotite also change. The isotope characteristics of the granites of the vatikha (Sr_i = 0.70868-0.70923 and εNd₂₅₅ from -8.9 to -11.9) and murzinka (Sr_i = 0.70419-0.70549, εNd₂₅₅ from -2.6 to +2.3) complexes suggest that the substratum of the former was the Proterozoic granite-gneisses, and of the second - the rocks of the newly formed crust, possibly similar to the Silurian-Devonian volcanogenic-sedimentary rocks, which contact with the murzinka granites at the west.

The plume-dependent magmatism is widespread and well justified. The bulk of it is represented by flood basalts, basalts of oceanic islands (OIB), and basalts of oceanic plateaus (OPB), though the whole scope of plume magmatism is very diverse. A noticeable role among them is played also by acid (silicic) magmatic rocks - rhyolites and granites. Two main types of plume magmatism are recognized. The first belongs to Large Igneous Provinces (LIP) and is thought to be born at the Core-Mantle boundary within structures, called superswells, that produce giant, short-living mantle upwellings, resulting in abundant volcanism on the Earth’s surface. The second type is represented by linear volcanic chains characterized by regular age progressions. They are formed by single plumes - thin ascending mantle flows, acting during longer periods of time. It is shown that the abundance of silicic magmatism strongly depends on the type of the earth’s crust. Among flood basalts of continents, silicic magmatism is usually present, subordinate in volume to basalts and belongs to a bimodal type of magmatism. But in some cases LIP in continents are formed predominantly by silicic rocks; they are given the name Silicic LIPS, or SLIPS. In oceans, LIP are fundamentally basaltic with no considerable volume of silicic volcanics, if any. The time-progressive volcanic chains in continents are rare and usually comprise a noticeable silicic component. In oceans, the chains are composed mostly of basalts (OIB type), though in the top parts of volcanoes more acid and alkaline differentiates are present; usually they lack rhyolites and granites, except the cases of a presence of some strips of continental crust or anomalously thick oceanic crust. This review can lead to a thought of an important role of melting of continental crust in formation of plume-dependent rhyolite-granite magmatism. As for the Urals, the proofs for a presence of plume-dependent magmatism in its history were presented only recently. Among the plume episodes, some are characterized by presence of silicic components, in particular: Mashak (1380-1385 Ma), Igonino (707-732 Ma), Man’khambo (mainly Cambrian), Ordovician Kidryasovo, Stepninsky (Permian) and Urals-Siberian (Triassic).

Some problems appeared after determinations of the old age of dunite material in the ultrabasite massifs of the folded regions and zonal massifs on the continental plateaus: 1) the problem of equilibrium of zircon and olivine + pyroxene composition in ultrabasite; 2) the problem of different age of zircon in every massif of ultrabasite and the way of the zonal zircon crystal formation; 3) the problem of the origin of the most old dunite material in ultrabasite massives; 4) the problem of formation of zonal zircon crystals in dunite. Experimental investigation of phase equilibrium in MgO-SiO₂-ZrO₂ system showed that zircon able to crystallize coincidentally with olivine and pyroxene. It was found that zircon in dunite is stable to 1450°C. Zircon is replaced to baddeleite at more high temperature. It is shown that the zonal zircon crystal can be formed by its transformation to baddeleite and the inverse process. The mechanism of dunite material accumulation at partial melting of mantle peridotite and possible way of transport of the residue dunite to the surface in diaper form are considered. The difference between ultrabasite of the Platinum belt of the Urals and Alpine type of ultrabasite is discussed. It is proposed that massifs of the Alpine type ultrabasite were intruded сlose to the surface where they interacted with porous water. The interaction of hyperbasites with the pore fluid will lead to their intensive serpentinization, the redistribution of chromium and its concentration in the form of ore bodies.

Xenocrysts and megacrysts hosted in the rocks of Early Cretaceous olivine-basalt-basanite-nephelinite association that outcropped in erosion crater of Makhtesh Ramon (Natural Reserve of Mishmar ha-Nagev, Israel) are the topic of the current research. Magmatic rock association contains the wide spectrum of xenoliths trapped at different crustal levels. These are upper mantle, lower, and upper crustal xenoliths. Mantle xenoliths are represented by peridotites, olivine clinopyroxenites, clinopyroxenites, olivine websterites, websterites and their amphibole-bearing analogs. Lower crustal xenoliths are mafic granulites, such as metagabbros and plagioclasites, upper crustal xenoliths are the fragments of Neoproterozoic tuffs. Xenocrysts and megacrysts are fragments of xenoliths that chipped from them during their transportation to the surface. Different rate of xenoliths, xenocrysts, and megacrysts alteration by host magma and late fluids is a common petrographic particularity. The fluid alteration occurred at phreatomagmatic stage of magma crystallization. Alteration is observed by the appearance of new textures and products of reactional interaction. Xenocrysts and megacrysts are mainly represented by minerals that compatible with rock magmatic association. These are olivine, clinopyroxene, amphibole, nepheline, plagioclase, anorthoclase, apatite, magnetite, and spinel. Xenocrysts of quartz and orthopyroxene are incompatible to host rock magmatic association under-saturated in SiO₂. Main reasons determining interaction between magma and xenolith are rapid decompression, metamorphism and metasomatism. Xenocrysts are subjected to metamorphism that corresponds to high-temperature facies of contact metamorphism, up to the partial melting of xenocrysts. Metasomatism is smoothing out the composition of xenocrysts to the composition of the same minerals that crystallized from host melt. There are several important criterions, which permit to identify xenocrysts and divide them from phenocrysts. These are partial melting, solid-state decomposition, recrystallization of primary (before-trapping) textures, recrystallization and self-faceting of initially anhedral grains into the crystals with perfect habit. Chemical composition of xenocrysts has both mineral - geochemical indications of xenogenic origin and new-formed sings of alteration.

Geopetrological model of diamond-bearing fluid-explosive breccia formations is a well-structured system of the features that are typical of several similar formations in the Cis-Ural and West Ural areas of the Perm Krai. The model reflects a number of basic common factors in these structures’ morphology, their rock composition and the conditions for their formation. Regional and local geological positions featuring diamond-bearing formations as well as the parameters common for their widespread formation areas are characterized. The necessity of mineralogical and geochemical studies of black sand, while prospecting for diamond-bearing targets is highlighted. This will help identify specific mineral associations and geochemical anomalies typical of these widespread formation areas. The description of the geological structure, which the best-studied Efimov deposit, is given in detail. The description of this deposit is used as an example of illustrating the shape of breccia bodies and their polyphase structure, as well as describing their texture and rock structure specifics. Particular attention is paid to the petrographic characteristics of all kinds of fluid-explosive breccias, which to a different extent contain clastic, protomagmatic and newly formed fluidogenic material. The paper gives the characteristics and specifics of mineral grains of various origin, many of which are abundant in gas-liquid inclusions, characterized by block extinction, while quartz possess planar elements. Brought into focus are the differences in the diamond bearing capacity of rocks belonging to different successive evolution phases of fluid breccia formations. The model considered in the paper will make it possible in the course of studies of newly discovered breccia structures with a limited number of parameters to predict their missing features and assessment criteria with respect to possible beneficial mineralization.

U-Pb dating of the pyrochlore-group minerals from the Nb-rare metal ore deposits of ilmeny-vishnevogorsky carbonatite-miaskite complex of the Ural fold region was carried out. To date the individual pyrochlore crystals were used a new technique of local U-Pb SHRIMP-II dating which was developed at the CIR VSEGEI (St.Petersburg). In the case of high-U pyrochlore (with more than 2.5 wt % UO₂) a laser ablation and ICP-MS method was applied for U-Pb-dating. The studied isotope pyrochlore system indicates a multi-stage formation of rare metal niobium mineralization. The earliest age of ore formation (378 ± 4.9 Ma) is fixed by U-pychlore isotope systems of Potanino deposit. This stage of ore formation is probably associated with the final stages of the alkaline-carbonatite magmatic system crystallization. The next stages of ore formation (230 ± 1.5 Ma) are widely manifested in Vishnevogorsk and later on the Potanino deposit (217.2 ± 1.9 Ma) and were probably related to remobilization and redeposition of alkaline-carbonatite and rare metal substances.