scholarly journals AGE SPAN FORMATION IN GRANITOIDS OF UKRAINIAN SHIELD

2020 ◽  
pp. 12-16
Author(s):  
L. Stepanyuk ◽  
О. Hrinchenko ◽  
T. Dovbush ◽  
O. Ziultsle ◽  
N. Konoval ◽  
...  
Keyword(s):  
Ukrainian Shield ◽  
Open Pit ◽  
Isotopic Dating ◽  
Potassic Feldspar ◽  
Genetic Nature ◽  
Southwestern Area ◽  
Dating Method ◽  
Magmatic Replacement ◽  
Granitic Melt

The paper discusses Berdychiv type granitoids that have always stirred up interest among researchers of the Ukrainian Shield. These rocks include minerals that are uncharacteristic of granites - cordierite, sillimanite, andalusite - and are closely related to rocks of the supposed substratum. At the same time, there still remain questions about the genetic nature of Berdychiv granites. Despite the fact that most researchers treat these granites as intrusive (anatectic) formations, there are other concepts according to which these granites are considered to be the products of metasomatic transformation (magmatic replacement) of primarily argillaceous and marly series of substratum. The Stryzhavka open pit, which is located in the Upper Bug region of the Ukrainian Shield displays differently cataclised porphyry-like plagiogranitoids (predominantly, garnet-bearing varieties in its southwestern area, locally rock-forming potassic feldspar varieties), and garnet-bearing leucocratic granites similar to those of Berdychiv type granites. The monazites of biotite-garnet granodiorite and biotite-garnet granite were dated by uranium-lead (U-Pb) isotopic dating method. The monazite of granodioritеs is dated 2049,3±3,5 million years based on the upper intersection of concordia with discordia. Significantly lower values of age (about 15 million years younger) for the monazite selected from granite, approximating 2035,1±1,9 million years were established. We assume it to be caused by prolonged crystallization of granitic melt and rather early crystallization of more basiс granodioritic magma in comparison with granitic one. Thus, the duration of the granitoid formation uncovered in the Stryzhavka open pit exceeds 15 million years, which correlates accurately with the estimates for occurrence duration of the granitic melts, which gave rise to various granites of the Ukrainian Shield.

scholarly journals Uranium-Lead Geochronology on Monacite of Granites of the Lypnyazka Massif and its Framing (Ingul Megablock of the Ukrainian Shield)

2021 ◽  
pp. 71-79
Author(s):  
L.M. Stepanyuk ◽  
◽  
S.I. Kurylo ◽  
V.O. Syomka ◽  
T.I. Dovbush ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Ukrainian Shield ◽  
Upper Crust ◽  
Isotopic Dating ◽  
Granite Massif ◽  
Rare Elements ◽  
The Village

The Lipnyazka massif is located in the Dobrovelychkivsky district of the Kirovohrad region, v. Lipnyazka and further south. Structurally, it is located within the Bratskyy Synclinorium of the Ingul megablock and coincides with the Mikhailovsky anticline. The main petrotype of the massif rocks are porphyry-like granites, often with a gneiss-like texture, aplito-pegmatoid, pegmatoid granites and pegmatites. The latter most often form secant vein bodies. Uranium-lead isotopic dating of granitoids of the Lipnyazka granite massif has been performed, with which a number of deposits and ore occurrences of rare elements, primarily lithium, are spatially and probably genetically connected. The age of porphyry-like granites (2032 ± 6 million years), which is the main petrotype of rocks distributed in the area of the village of Limestone and pegmatoid granites (2027 ± 1 million years), which cut porphyry-like in the form of vein bodies. Aplithoid framed granites (2046 ± 8 million years old), common in the area of the mouth of the Sukhyi Tashlyk River (Dobryanka village), are somewhat older. Based on the results of determining the isotopic composition of strontium in the accessory apatite of granites, a conclusion was made about the upper crust source of granites of the Lipnyazka massif (87Sr/86Sr – 0.730-0.785).

scholarly journals Overview in situ U - Pb isotopic dating method on cassiterite. Application to determine for Sn - W mineralization age of the Lung Muoi deposit in the Pia Oac region, Cao Bang province

2020 ◽  
Vol 61 (5) ◽  
pp. 1-10
Author(s):  
Luyen Dinh Nguyen ◽  
Hieu Trung Pham ◽  
Nhuan Van Do ◽  
Thai Ngoc Tran ◽  
Thu Thi Le ◽  
...  
Keyword(s):  
New Age ◽  
Mineral Research ◽  
Isotopic Dating ◽  
Icp Ms ◽  
The World ◽  
Dating Method ◽  
Mineralization Age

In recent years, the U - Pb isotopic dating method for cassiterite minerals has been used by many scientists around the world in the field of mining and mineral research. This paper presents an overview of the history, development and results achieved using this dating method in the field of mining and mineral research in the world. The LA - ICP - MS U - Pb isotopic dating method for cassiterite minerals was used at the Lung Muoi Sn - W deposit in Pia Oac region, Cao Bang province. The result of LA - ICP - MS U - Pb cassiterite isotopic dating shows the Sn - W mineralization in the Lung Muoi deposit crystallized at 88 Ma. The new age results in this paper are very consistent with the previously published results of the Pia Oac granite.

scholarly journals Revisiting stratigraphic complexes and regional stratigraphic scheme of the lower precambrian of the Ukrainian shield

2019 ◽  
pp. 40-48
Author(s):  
V. P. Kyrylyuk
Keyword(s):  
Material Composition ◽  
Ukrainian Shield ◽  
Historical Period ◽  
The West ◽  
Isotopic Dating ◽  
Early Precambrian ◽  
Stratigraphic Unit ◽  
Leading Role ◽  
Tectonic Position

The stratigraphic scheme of the Early Precambrian of the Ukrainian Shield bears a number of differences from the traditional regional stratigraphic schemes: 1) along with stratified subdivisions it includes intrusive and ultrametamorphic complexes that are not accounted for in the “Stratigraphic Code of Ukraine”; 2) The leading role in creating the regional stratigraphic scheme was played by isotopic dating results; 3) The Stratigraphic Scheme does not include the taxon “complex”, as it is described in the “Stratigraphic Code of Ukraine”. According to “Stratigraphic Code of Ukraine”, “Complex” is the largest regional stratigraphic unit that corresponds to a large geo-historical period. Due to the absence of the taxon of “complex” in the regional Precambrian stratigraphic scheme, the main stages of geological development of the region in the Precambrian have not been identified for the Ukrainian Shield. The first article of the cycle is devoted to the feasibility of introducing the taxon of “complex” in the regional stratigraphic scheme on the materials of the Ukrainian Shield. It notes that most of the series in the current stratigraphic scheme correspond to complexes by their level of study and their historical and geological content. Such units are Konkska, Kryvorizka, Teterivska, Ingulo-Inguletska and some other series. Each of them can be separated into several series. The Dniestrovsko-Bugska and Bugska series, the West-Priazovska and Central-Priazovska series of granulite-gneiss complexes are artificially separated and shown as different age subdivisions in the current stratigraphic scheme. These series should be included in the Bug Area and Azov Area complexes, but their volumes and names need clarification. Amphibolite-gneiss complexes can be included in the stratigraphic scheme without dismemberment into series, since they correspond to a large geohistoric stage marked by the peculiarities of their material composition and structural-tectonic position.

scholarly journals Uranium-Lead by Monacite Geochronology of Granites Distributed in the Middle Current of ihe River Ros (Ros-Tikich Megablock Ukrainian Shield)

2021 ◽  
pp. 89-93
Author(s):  
Т.I. Dovbush ◽  
◽  
L.M. Stepaniuk ◽  
О.V. Ziultsle ◽  
Т.B. Yaskevych ◽  
...  
Keyword(s):  
Geological Structure ◽  
Ukrainian Shield ◽  
Isotopic Age ◽  
Isotopic Dating ◽  
Leading Role ◽  
The Village ◽  
Good Agreement

Granitoids play a leading role in the geological structure of the Ros-Tikich megablock. The rocks of the Ros-Tikich series, which form the supercrystalline base here, have survived among the granitoids only in the form of some remnants of different sizes. In the coastal outcrops of the middle course of the river Ros (east of Bila Tserkva) and in the quarries located near the river, the most common are two-feldspar granitoids, isolated as part of two complexes – Uman and Stavyshche. Plagiogranitoids and supercrustal rocks have survived among them in the form of separate fragments. Of the accessory uranium-containing minerals, zircon and titanite are present in two-field spar granites, and monazite was found in single samples of granites in which titanite was absent. The age of obscure porphyry-like granite discovered by the Ostrivsk quarry – 2063.5 ± 1.2 million years and uniformgrained granite, distributed in the quarry of the village of Bovkun – 2042.5 ± 8.6 million years. The obtained values of the isotopic age of these granites are in good agreement with the results of uranium-lead isotopic dating of zircons from twofeldspar granites of the Ros-Tikich megablock (1990-2080 million years). This allows us to propose to combine the granites of the Stavyshche and Uman complexes into one Paleoproterozoic complex.

scholarly journals Kaersutite lamprophyres of the Pokrovo-Kyriivo massif (the Azov area, Ukraine): petrographic features, mineral composition, geochemistry

2020 ◽  
Vol 41 ◽  
pp. 42-53
Author(s):  
V.O. Gatsenko ◽  
◽  
S.V. Kushnir ◽  
Keyword(s):  
Mineral Composition ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Mafic Rock ◽  
Ukrainian Shield ◽  
Open Pit ◽  
Tio2 Content ◽  
Fine Grained ◽  
Bottom Hole ◽  
Folded Structure

The paper represents results of the petrographical, geochemical and mineralogical studies of a dyke of porphyry-like mafic rock from the Pokrovo-Kyriivo massif of the Azov area, the Ukrainian Shield. This dyke of fine-grained rock has unique mineral composition as the main mineral in the groundmass is kaersutite. According to mineralogical and petrographic features, it can be identified as kaersutite lamprophyre. The Devonian Pokrovo-Kyriivo massif is located at a junction of the Azov Domain of the Ukrainian Shield and the folded structure of Donbas. This massif is composed of subalkaline (pyroxenite, gabbro) and alkaline (malignites, nepheline syenite) rocks which are cut by numerous dykes varying in composition from ultramafic to intermediate. The dyke of finegrained kaersutite lamprophyre was discovered in the bottom hole of the drillhole 36, where it is intruded into mediumgrained gabbroids and pyroxenites. The groundmass of the rock is composed of kaersutite, titanomagnetite, albite, chlorite, titanite, pyrite, chalcopyrite, apatite, monazite. The phenocrysts are represented by chlorite and talc pseudomorphoses after a diamond-shaped mineral with shortened obtuse angles. According to electron microprobe analysis, kaersutite has low TiO2 content and intermediate mg# values of 0.54—0.67. According to the chemical composition, studied kaersutites differ from the same mineral in the microgabro dyke in the Pokrovo-Kyriivo massif, and from kaersutites in camptonites of the Khlibodarivka open pit in the Azov area. At the same time, it is similar to kaersutites from camptonites of the Novoukrainka dyke field of the Inhul terrane. Kaersutite lamprophyre also differ from dyke rocks of the Pokrovo-Kyriivo massif by the absence of clinopyroxene, mica, ilmenite and low content of TiO2 in titanomagnetite, which does not exceed 6 %. This is due to a low TiO2 content in the rocks (up to 3.5 %), relative to other dyke gabbro of the area. According to mineralogical-petrographic and chemical characteristics, kaersutite lamprophyres are unique rocks that have no direct counterparts in the Azov area or on the Ukrainian Shield in the whole.

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