Sokolivsky (Inguletsky) quarry is located in the South-Western (Sokolivsky) suburb of Kropyvnytsky. The quarry exposes typical porphyry granites of the Kropyvnytsky (Kirovohrad) type. The granites are biotite, in some areas garnet-biotite, light gray in the lower ledges and pink in the upper ones. Granites are characterized by wide variations in the content of biotite and garnet, which is likely due to the layered structure of the stratum, which was transformed into granites as a result of ultrametamorphism, but was not homogenized due to incomplete (partial) melting. As a result of studying the anatomy of accessory zircon crystals by optical microscopy, heterogeneous relict zircon nuclei of substrate rocks were found in the middle of the crystals, which indicates a crustal source of the ancestral granite melts that formed the Kropyvnytsky massif. The age of the granites of the massif was determined by the U-Pb isotope method using monazite. It was found that the heterogeneous biotite-microcline-plagioclase granite (sample 18/23) was formed 2043 +/- 30 Ma and the gray-pink biotite-difeldspar (sample 19/23) - 2031 +/- 2.5 Ma. The difference in the time of formation by almost 10 million years is most likely due to the long (more than 10 million years) existence of the granite melt and different times of crystallization of monazite, caused by differences in the chemical composition of the melt, in particular the activity of calcium and phosphorus in different parts of the magmatic center.
We conducted a geochronological and petrological study of felsic igneous rocks associated with the formation of the Soroky and Berestova greenstone structures in the Azov Domain of the Ukrainian Shield. According to U-Pb LA-ICP-MS dating, granitoid intrusions in the Soroky and Berestova greenstone structures formed at 3003±31 Ma and 2931±84 Ma, respectively. In contrast, trondhjemite found as fragments in the tectonic zone was dated at 3224±37 Ma. These ages define the interval of greenstone belt formation in the Azov Domain, spanning from 3220 to 3000 Ma. Geochemical data indicate that metarhyolites, which form the greenstone structures, along with tonalites and granodiorites that intrude them, resulted from the partial melting of juvenile crustal rocks, characterized by short crustal residence times. Trondhjemite found in the tectonic zone was generated by melting of a protolith with an extended crustal residence time. The obtained data indicate a significant role of the melting of older continental crust in the origin of greenstone belts in the Azov Domain of the Ukrainian Shield.
Based on studies of the fluid phase of inclusions in minerals of rocks of different genetic types from the Earth's lith osphere, the relationship (connection) of individual parameters: pressure - temperature, pressure - density and temperature - density - in the creation of fluid pressure, in particular ultrahigh, in the rock environment during magmatic, metamorphic and hydrothermal mineral formation is shown. Using the example & iukcy; of studying ultrahigh fluid pressures during the crystallization of quartz crystals of the "Marmarosh diamonds" type, it is proven that ul trahigh fluid pressure is associated with the internal chemical transformation of the initial water oil fluid with the accumulation of a high density gas phase (& Scy;& Ncy;4) as the main barogenic factor of ultrahigh fluid pressures. For indi vidual gold ore objects of the Ukrainian Shield, high fluid pressure in vein quartz were caused by the oxidation of graphite of host rocks to & Scy;& Ocy;(2) with its subsequent active participation in the formation of vein gold mineralization. This is evidenced by the closeness of the isotopic composition of carbon & Scy;& Ocy;(2) of fluid inclusions in quartz and an thraxolite veins and in graphite and carbonate of host rocks. According to the results of determinations of fluid pressure of mineralogenesis among different types of lithosphere rocks, it follows that fluid pressures of mineral ogenesis in the rock environment, including ultrahigh ones, are the product of mineral, chemical and other trans formations in the rock fluid system against the background of geodynamic and geochemical processes at a specific object. According to geological data, fluid pressure of crystallization of minerals of basaltoid magmas during their penetration into the rock and water (oceanic) environment, as well as the magnitude of the pressures of inclusions of water salt solutions in quartz from Volyn pegmatites, are commensurate with the depth of mineral crystalliza tion. The ultrahigh fluid crystallization pressure of the Carpathian "Marmarosh diamonds" appears to be inde pendent of depth., although some individual values may be commensurate with lithostatic pressure. There is not enough reason to judge the commensurability of fluid pressure from fluid inclusions in minerals of metamorphic rocks with the probable depth of their crystallization.
Synthesis in a fluid with supercritical parameters is a universal method for high temperature growth under high pressure of various substances. By the method of fluid synthesis at a pressure of up to 200 MPa and a temperature of 500700 degrees C, carbon powder was obtained from carbon black and activated carbon by the reverse Boudoir reaction, which was identified as cubic graphite. This experiment continues previous developments on the topic of fluid synthesis of carbon modifications. The equipment on which the experiments were conducted allows to create in a short time the specified conditions in a wide range of pressure, temperature and time values. The schematic diagram of such equipment is presented in many works published by us earlier. It was experimentally found that in the case of the formation of carbon structures from the starting material (soot or activated carbon) at the PT parameters specified in the experiments, the cubic graphite structure dominates. The induction of the latter from soot occurred at higher values of P, T, while for activated carbon the main parameter of synthesis is its duration at lower values of P, T. The new results expand the picture of the formation of the cubic graphite phase depending on the thermodynamic parameters of the experiment and fit into the framework of the previously proposed new model of the formation of carbon phases. It is shown that pressure; temperature and time significantly affect the formation of cubic graphite. In particular, pressure is the main factor in a significant increase in the yield of powder during synthesis. Temperature and time also increase the yield of cubic graphite, but have their own optimum. To work out the optimal modes for obtaining cubic graphite of a perfect structure, we can use the results we obtained of the influence of various starting substances during its synthesis.
The Carpathian region is very poor in rare earth minerals. Until now, only Ce and Y phosphates were known in ancient rocks of the Marmarosh massif. The discovery of silicate from the epidote supergroup in the spilitized Mesozoic (J(3)-K-1) basalts of the Chyvchyn suite was the first in the Ukrainian Carpathians. A characteristic feature of the basalts according to X-ray fluorescence analysis is the content of REE and Co above the Clark content and an increased content of other rare elements - Ba, Sr, Zr, Cr, Rb. According to the results of microprobe chemical analyses, the mineral was identified as allanite-(Ce) with a deficiency of REE and Fe, which are compensated by Ca and Al, respectively. Allanite in paragenesis with quartz (chalcedony), titanite magnetite, calcite and chlorite forms reniform aggregates up to 100 mu m in size, confined to the contact zone of the effusive with the xenolith of the terrigenous-carbonate rock, near the calcite vein. Microscopic brownish-brown individuals of allanite (10-20 mu m) in aggregates are anisotropic, weakly pleochroic. The average composition of the mineral according to eight measurements corresponds to the formula Ca1.48REE0.46Al2.26Fe0.74Si3.07O12(OH). The mineral was formed as a result of the interaction of basaltic magma (probably alkaline specialization) with terrigenous-carbonate rock under conditions of greenschist metamorphism, closer to epidote-amphibolite (300-500 degrees C). It was assumed that the reniformshape of the aggregates is inherited from organogenic residues in limestones. The liquation hypothesis, which is based on the formation of separated spherical drops of silicate-carbonate melt as a result of the interaction of basaltic lava with limestone, seems more likely. Allanite in paragenesis with other minerals is the result of crystallization of this melt. The liquation hypothesis of the formation of reniform aggregates is consistent with visual facts, in particular with the shape and distribution of aggregates, similar mineral composition, zonal structure, etc. The discovery of allanite among the basalts of the Chyvchyn suite enriched in rare elements opens up the prospect of searching for other minerals with these elements.
