Ingul Megablock Research Articles

The age of monzonites of the eastern part of the Korsun-Novomirgorod pluton (Ingul megablock of the USh)

The article presents the results of monzonites research of the eastern part of Korsun-Novomirgorod pluton. The pluton is situated in the northwestern part of the Ingul megablock. Besides basic rocks varieties — gabbro-anorthosite and rapakivi granites the rocks of monzonite composition of different genesis are widely presented here. Small bodies of monzonites form outputs among rapakivi granites of Shpola massif at the junction of tectonic structures of different rank. Monzonite is a hybrid rock which contains xenoliths of frame rock and possibly ancient dyke formations. Zircon is represented by several generations, which are distinguishable by optical studies, as well as by different U / Th ratio. Some grains contain a nuclei and zircon inclusions, appearance of which was determined by the process of contamination. All fractions obtained discordant zircon age values. Dating calculated by isotope ratio 207Pb / 206Pb has been taken as the most reliable. Due to the presence of relict zircons received isotopic age of the figures are overstated and do not reflect the formation of monzonite. As the maximum possible monzonite age we can take a minimum age, calculated by 207Pb / 206Pb — 1.740 Ma. The assumption about the formation of monzonite melt as a result of contamination of basic magma by ancient crustal rocks of acid composition has been given, which does not contradict the results of the study of the isotopic composition of strontium, neodymium, and geochronological data.

Special features of distribution of seismic waves propagation velocity in the Earth crust in the area of uranium deposits (Kirovograd ore area of Ingul megablock of the Ukrainian Shield)

Special features of distribution of seismic waves propagation velocity in the Earth crust in the area of uranium deposits (Kirovograd ore area of Ingul megablock of the Ukrainian Shield)

Density heterogeneity of the Earth’s crust of the Ingul megablock of the Ukrainian Shield according to the data of three-dimensional gravity modeling

Density heterogeneity of the Earth’s crust of the Ingul megablock of the Ukrainian Shield according to the data of three-dimensional gravity modeling

Mafic dykes of Ingul megablock (Ukrainian Shield): relationship of surface and deep structures of the lithosphere, fault tectonics and geodynamics

Morphology, structure position, formation and dyke saturation of the swarms were ascertained. New dyke swarms of «second range» were established. Intersection areas of the dyke swarms «traces» were defined. They are considered as the magmatic focuses at the different lithosphere depths, which are connected with cells of the repeatedly activated plume. Analysis of the Earth crust deep structure and peculiarities of mantle heterogeneities in the proposed magmatic focuses of dykes permitted us to conclude, that they are associated with pulsing mantle plume. Under its influence melted mantle material moved forward from greater depths in the east to smaller one in the west. It found the escape as dykes in the north-western faults but Golovanevsk suture zone limited further extension of material.

Scarn Gold Mineralization of the Bandurka Ore Occurrences (Ingul Megablock, Ukrainian Shield)

Scarn Gold Mineralization of the Bandurka Ore Occurrences (Ingul Megablock, Ukrainian Shield)

Уран-свинцевий ізотопний вік гранітів Вознесенського масиву (Інгульський мегаблок Українського щита)

Уран-свинцевий ізотопний вік гранітів Вознесенського масиву (Інгульський мегаблок Українського щита)

Глибинна будова Iнгульського мегаблока за даними геоелектричних дослiджень

Глибинна будова Iнгульського мегаблока за даними геоелектричних дослiджень

Geofluids and up-to-date display of activization of the Ingul megablock of the Ukrainian Shield

High degree of geological-geophysical studies of crustal processes combined with analysis of 3D P-velocity model of the mantle under the Ukrainian Shield and its southern surrounding up to the depth of 2500 km allowed to correlate manifestations of defined possible super-deep fluid process with hydrocarbon-gas-condensate occurrences within the limits of Novokonstantinov ore field.

Минералого – петрографические особенности долеритов Розановского дайкового поля (Южная часть Ингульского мегаблока Украинского щита)

The authors of this paper were the first to study Mafic dyke rocks drilled in deep boreholes in the southern part of the Ingul Megablock (IMB) of the Ukrainian Shield. The drilled dykes refer to the under-explored Rozanovka Dyke Field (RDF). The objective of the work was to determine the mineralogical and petrographical features of RDF dyke rocks which could further be used as an indicator to refer them, as well as other IMB mafic dykes, to certain regional magmatic associations. Under the authors' tentative examination is the mineralogy of dyke rocks as well as the chemistry of the main rock-forming minerals: plagioclase, pyroxenes, and olivine. It has been established that among the studied samples there prevail cainotypic olivine dolerites showing mineralogical and petrographical features of the Proterozoic dolerite-diabase association. Being an indicator for the subplatform stage of ancient cratons development, the association is viewed as a paleoanalog of the continental plateau-basalt Phanerozoic association. Practical application of this finding is in identifying the potential Cu-Ni specialization of many well-known dolerite-diabase complexes. A more accurate definition of the petrography, geotectonic position and metallogenic specialization of RDF dolerites requires further geochemical research.

Геологічна позиція та речовинний склад пікритів Новоукраїнського дайкового поля (Інгульський мегаблок Українського щита)

Геологічна позиція та речовинний склад пікритів Новоукраїнського дайкового поля (Інгульський мегаблок Українського щита)

Peculiarities of distribution of seismic velocities in the Earth’s crust of the Kirovograd ore district of the Ingul megablock of the Ukrainian Shield. 2

As a result of studying the peculiarities of the seismic waves velocities in the Kirovograd ore district Earth’s crust and its structures some regularities of the velocity characteristics of the structures under studying were revealed. It is shown that these structures were confidently marked out in the field of the seismic wave velocities. It opens some new possibilities for tectonic zoning of the Kirovograd ore district and the Ukrainian shield territory.

An experience in constructing a three-dimensional geoelectric model based on the results of 2D inversion of magnetotelluric field parameters on an example of the Ingul megablock

Based on dozens of MTS curves involving magnetic variation of parameters 2D inversion of 8 mutually perpendicular profiles covering the area from 30 to 320 ◦E and from 47,8 to 49,50 ◦N was first performed. The obtained results of the simulation were used to construct a three-dimensional model of the geoelectric region using a complex software developed by the authors. The model indicates that the subsoil of the region studied to a depth of 60 km, has got numerous conductivity heterogeneities. The depth of the roof, of the most reliably selected objects, occurs below 6 km. The most conductive parts of objects (with a resistance of less than 10 ohm m and the integral conductivity of more than 50 % of the total) are located at the depths of 20—40 km. The most conductive parts of anomalous objects are consistent with Smelyansk and Bobrinets fracture zones and with their cross-section with Golovanev suture zone.

The development of the Ingul megablock of the Ukrainian Shield during the formation of the Novoukrainsky and Korsun-Novomirgorod Plutons

Analysis of geological structure and the studies of composition of magmatic complexes of the Ingul block of the Ukrainian Shield makes possible to come to some conclusions on its deep structure during the period of 2,1-1,7 Ga. It has been found that the melts of the initial phases of the Novoukrainka and the Korsun-Novomirgorod plutons were differentiated at the border the crust - the mantle, and the melts of the final phases were differentiated within the crust. The appearance of the melting source at the border the crust - the mantle was produced by the melt supply along the permeable "transforming" zone. Appearance of crustal asthenosphere was caused by heat and material supply from the mantle asthenosphere. Combination of metasomatic and magmatic processes, as well as conductive heating lead to production of vast crustal melting source. Vertical component of the deep process during formation of the Novoukrainka and Korsun-Novomirgorod plutons is the same or similar but during the period 2,0-1,6 Ga lateral decrease of melting sources is noticed. Possibly, it was that period, which could be considered as the time of undepleated mantle formation, when its composition approaches lherzo-lite one and the temperatures become lower than its solidus temperature under the major part of the Ukrainian Shield.

Features of the distribution of seismic velocities in the earth's crust of the Kirovograd ore region of the Ingul megablock of the Ukrainian Shield. 1.

In consequence of studying of the peculiarities of the seismic waves velocities in the Kirovograd ore district and its structures Earth‘s crust some regularities of the velocity characteristic of the structures under studying were revealed. In following in construction of the complex 3D geology-geophysical model of the Kirovograd ore district Earth‘s crust these results may be used.

Precambrian of the Ukrainian Shield and Plate Tectonics

By the example of the Ukrainian Shield Ingul megablock the reconstruction features of the plate tectonic development of the lithosphere in the Archean - Early Proterozoic have been shown. We analyze the geological model proposed by E. B. Glevassky in comparison with the tectonophysical data on the megablock. The proceedings of the independent studies are consistent with each other within the framework of the plate tectonic approach taking into account PT-conditions of the Early Precambrian. In contrast to the geological model providing the collision nature of the megablock granitoids, the tectonophysical model establishes that most granite massifs were formed in the process of microplates pushing apart.