scholarly journals Stratigraphic-lithological factors of the location of gold mineralization in the central part of the Bukantau Mountains in Uzbekistan

2021 ◽  
Vol 937 (4) ◽  
pp. 042084
Author(s):  
A Tangirov ◽  
T Ishboboev ◽  
B Urunov

Abstract The leading role in the placement of gold mineralization in the Bukantau mountains belongs to structural and lithological factors. For gold-ore and gold-silver occurrences, sandy-shale strata of the flyschoid and olistostrome formations are favorable, then, rocks of the volcanogenic-dolomite-siliceous formation and then the carbonate formation (Okzhetpes type). The leading types of near-ore hydrothermal alteration of the host rocks in the studied deposits are silicification and, to a lesser extent, carbonatization and sericitization. They are accompanied by chloritization, biotitization, argillization, etc. Gold ore deposits and ore occurrences of sulfide-disseminated ores are confined mainly to the deposits of the Karashakh suite of the Middle Carboniferous (C2b + m1 kr). Moreover, gold-sulfide mineralization in the rocks of the Karashakh Formation is unevenly distributed.

LITOSFERA ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 706-716
Author(s):  
N. N. Ankusheva ◽  
R. V. Kuzhuget

Research subject. The paper presents data on the mineralogical, geochemical and fluid inclusion features of the Southern Ak-Dag gold-sulphide-quartz ore occurrence in Western Tuva.Methods. Mineral formation temperatures, salt composition and fluid salinity were examined using a Linkam TMS-600 cryostage and an Olympus BX 51 microscope. The chemical composition of samples was identified using a MIRA 3 LMU (Tescan Orsay Holding) scanning electron microscope equipped with INCA Energy 450+XMax 80 and INCA Wave 500 microanalysis systems; BSE photos were taken by Tescan Vega 3 and Hitachi ТМ-1000 SEM instruments.Results. The ores under study were found to contain both high-grade and medium-grade gold with an Ag content of up to 17.05 wt %. The average gold fineness comprised 904 ‰, ranging from 830 to 928 ‰. According to fluid inclusion data, gold-sulphide-quartz veins were formed at temperatures of 280–240 °C and pressures of 0.8–1.2 kbar from aqueous fluids having a salinity of 8.6–6.4 wt % NaCl eq. The narrow range of fluid salinity at decreasing temperatures and the prevalence of high-grade gold in sulphide-quartz veins indicate a relatively high rate of mineral formation in a narrow permeable zone without any significant interaction with host rocks or mixing with meteoric waters.Conclusions. Gold mineralization in the Southern Ak-Dag ore occurrence, which was formed within one ore substage, corresponds to the type of gold-galena-chalcopyrite with barite. The established similarity of native gold in the Southern Ak-Dag occurrence and other deposits in the Aldan-Maadyr ore cluster in terms of P-T parameters of ore formation and mineralogical and geochemical features, as well as association of the ore mineralization with beresites, indicate the possibility of discovering industrial ore deposits in the region and confirm its paragenetic relation with Devonian magmatic activity.


2013 ◽  
Vol 828 ◽  
pp. 1-10
Author(s):  
Adilkhan Baibatsha ◽  
Kulyash Dyussembayeva ◽  
Aimkhan Kassenova

The gold-sulfide deposit Southern Ashaly is localized in carbonaceous terrigenous formation (black shale strata) of the middle carboniferous (Bukon suite, which is the ore-hosting for super large deposit Bakyrchik). The Southern Ashaly is at the exploration stage and according to preliminary estimates of the expected resources belongs to a large deposit in scale. Ore gold mineralization of such level as Southern Ashaly in southwestern Kalba is found for the first time and gives hope for the discovery of such objects in the Boko Vassilyevskoye ore field. Ore-hosting at the field Southern Ashaly is carbonaceous terrigenous formation of the middle carboniferous, with no visible signs of volcanic formations. But, it was revealed, at microscopic research by us, paragenetic relation of the gold mineralization with small intrusions of plagiogranites and zones of plagiogranite porphyry dykes and found volcano-sedimentary rocks (aleuritic tuffsandstone, tuff breccia) which have undergone hydrothermal-metasomatic changes. The vein-disseminated gold-sulfide mineralization is associated with beresitizated plagiogranites and plagigranite-porphyries and hydrothermally altered tuff sandstones, tuff breccia and carbonaceous shales. Southern Ashaly unlike Bakyrchik deposit which contains invisible gold in sulfides, all the gold is concentrated in the pyrite mainly in the form of micro-sized (1-5 µm or less) in arsenopyrite is noted rarely.


2021 ◽  
Vol 40 (3) ◽  
pp. 28-40
Author(s):  
K.N. Dobroshevsky ◽  
◽  
N.A. Goryachev ◽  
◽  

An interpretation of the first obtained Re-Os dating of pyrite and arsenopyrite of the Malinovsky gold ore deposit is given. A comparison of the obtained data and the known dates of the ore-bearing granitoids of the ore field made it possible to determine the age of mineralization at 100-90 Ma. This age corresponds to the time of completion of the Alb-Cenomanian transform margin of Asia continent geodynamic setting with significant left-shear kinematics, as indicated in the article by the structural features of the localization of ore bodies and magmatic bodies. The distribution of gold ore deposits in this time within the Sikhote-Alin orogenic belt and in the shear structures of the south of the Korean Peninsula are noticeably shown.


2021 ◽  
pp. 40-67
Author(s):  
Aleksander Chernykh ◽  
Alexey Shirobokov ◽  
Irina Arsentieva

The Elegest-Mezhegei, Aptara, and Shivilig forecasted gold ore clusters and the Kharalyg and Irbitei forecasted gold-silver-polymetallic ore clusters were distinguished within the East Tannu-Ola iron-copper-polymetallic-gold ore region, based on examination of historical and new geological, geochemical, and metallogenical data. Subsequently, the Urgailyg, Proezdnoe, and Chumurtuk forecasted gold ore fields were delineated within the Elegest-Mezhegei cluster; the Despen ore field was delineated within the Aptara ore cluster; and the Ovur-Ongesh ore field was outlined within the Shivilig cluster. In addition, the Ulug-Sailyg and Ak-Charinsk gold-molybdenum-copper ore fields were distinguished outside the ore clusters. The article summarizes the investigation history, geological-structural position, geological features, and geochemical specialization of the rocks of the East Tannu-Ola region. Descriptions of the ore clusters embrace peculiarities of their geological structure, ore mineralogy, and native gold, as well as parameters of the gold-sulfide-quartz, goldskarn, gold-containing polymetallic VMS, and porphyry molybdenum-copper mineralized zones. The conclusions highlight the metallogenic epochs and distribution regularities of the gold and gold-containing mineralization within the region studied.


Author(s):  
Д.Б. Давыденко ◽  
С.Г. Парада

Приведены результаты металлогенического анализа новых данных, полученных в ходе проведения геолого-поисковых и региональных геофизических работ на территории Донецкого бассейна, представляющего центральный фрагмент Днепрово-Донецкой рифтогенной системы. По результатам металлогенического анализа и математической обработки геофизических данных, включающих оригинальную технологию объектно-ориентированной фильтрации, установлены полихронность и полигенность золотого оруденения, соответствующие полиэтапному развитию Донецкого авлакогена. В составе золотоносных руд вычленяются два основных типа: 1) крупнообъемные зоны и залежи золото-сульфидно-прожилково-вкрапленной минерализации в песчанико-сланцевых углеродистых толщах, относящихся к осадочно-(метаморфогенно)-гидротермальному генетическому классу, связанные с литогенезом и метаморфизмом каменноугольных углеродистых отложений на доорогенном этапе развития авлакогена (Бобриковское и др. месторождения) 2) эпитермальные кварцевые жилы и локальные жильно-прожилковые зоны золото-серебряно-полиметаллической минерализации, связанные с развитием вулкано-плутонических аппаратов центрального типа на этапе мезозойской тектоно-магматической активизации авлакогена, выделяемые по геофизическим данным (Керчикское и др. рудопроявления). Отнесение к осадочно-(метаморфогенно)-гидротермальному генетическому классу золотоносных минерализаций бобриковского типа обосновано особенностями локализации, размещения и вещественного состава руд, а также особенностями геологического строения Донбасса, свойственными классическим рудным районам с подобным типом оруденения в углеродисто-терригенных (черносланцевых) формациях: внутриконтинентальная позиция складчатых структур и отсутствие гранитоидного магматизма, отчетливо выраженная асимметрия складчато-разрывных структур, сочетание углеродисто-терригенных и карбонатных формаций различной степени их постседиментационного преобразования, наличие стратифицированной сульфидной минерализации. Выделение мезозойских вулкано-плутонических структур центрального типа, с которыми связана эпитермальная золотоносная минерализация керчикского типа, основано на выявлении изометричных положительных аномалий магнитного поля, сопряженных с изометричными отрицательными аномалиями гравитационного поля, а также выходами магматических пород. Выявленные в Западном Донбассе к настоящему времени золотоносные руды бобриковского типа представляют собой объекты ранней доорогенной минерализации золото-сульфидно-прожилково-вкрапленного типа в углеродисто-терригенных комплексах. Выявленные в Восточном Донбассе к настоящему времени золото-серебряно-полиметаллические руды керчикского типа представляют собой позднепродуктивную стадию, связанную с регенерацией и перераспределением доорогенных золотоносных минерализаций на этапе мезозойской тектоно-магматической активизации The results of a metallogenic analysis of new data obtained during geological exploration and regional geophysical work in the Donets basin, which is the central fragment of the Dnieper-Donetsk riftogenic system, are presented. According to the results of metallogenic analysis and mathematical processing of geophysical data, including the original technology of object-oriented filtering, the polychronism and polygenicity of gold mineralization is established, corresponding to the poly-phased development of Donetsk aulacogen. In the composition of gold ores, two main types are distinguished: 1) large-volume zones and stratiform deposits of gold-sulfide-vein-disseminated mineralization in sandy-shale carbon strata, belonging to sedimentary (metamorphic) -hydrothermal genetic class, associated with lithogenesis and metamorphism of stony-carbon metamorphism at the preorogenic stage of development of aulacogen (Bobrikovskoye and other deposits) 2) epithermal quartz veins and local vein-vein zones of gold-silver-polymetallic mineralization associated with the development of central-type volcanic-plutonic apparatuses at the stage of Mesozoic tectonic-magmatic activation of aulacogen, identified according to geophysical data (Kerchik and other ore occurrences). The assignment to the sedimentary (metamorphogenic) -hydrothermal genetic class of Bobrikovsky type gold-bearing mineralizations is justified by the features of localization, distribution and material composition of the ores, as well as the peculiarities of the geological structure of the Donbass, characteristic of classical ore regions with a similar type of mineralization in carbon-terrigenous (black shale) formations the position of folded structures and the absence of granitoid magmatism, a pronounced asymmetry of folded-discontinuous structures, with the carbon-terrigenous and carbonate formations of varying degrees of their post-sedimentation transformation, the presence of stratified sulfide mineralization. The isolation of the Mesozoic volcanic-plutonic structures of the central type, which are associated with the zythermal gold-bearing mineralization of the Kerchik type, is based on the detection of isometric positive anomalies of the magnetic field, coupled with isometric negative anomalies of the gravitational field, as well as the outputs of igneous rocks. Gold-bearing ores of the Bobrikov type identified in the Western Donbass to date are objects of early pre -ogenic mineralization of a gold-sulfide-vein-disseminated type in carbon-terrigenous complexes. The gold-silver-polymetallic ores of the Kerchik type discovered in the East Donbass to date represent a late-productive stage associated with the regeneration and redistribution of pre -ogenic gold-bearing mineralizations at the stage of Mesozoic tectonic-magmatic activation


2017 ◽  
Vol 743 ◽  
pp. 417-421 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Yackov Yur’evich Bushuev

The Podgolechnoe deposit, which belongs to the alkalic-type (A-type) epithermal gold-ore deposits, lies in the Central Aldan ore district (Russia). Gold-ore mineralization is associated with a volcano-plutonic complex made of rocks of the monzonite-syenite formation (J3–K1). The ore bodies are localized in the crushing zones developed after crystalline schists, gneisses, and granites of the crystalline basement complexes (Ar–Pr). Metasomatic alterations in host rocks have potassic specialization. Vein ore minerals are adular, fluorite, roscoelite, sericite, and carbonate. Ore minerals are pyrite, galena, sphalerite, cinnabar, brannerite, monazite, bismuth telluride, stutzite, hessite, petzite, montbraite, and native gold. The deposit has been explored as a gold-ore deposit, however, due to complex composition of ores there is a need to reveal the possibilities of the integrated development of this deposit. This could provide for a reserve increment and an increase in the gross recoverable value of ores due to the extraction of associated components.


Author(s):  
E. M. Nekrasov

The gold ore chimneys of 2 types have been shown to be developed at the near-surface deposits of gold and silver ores. These types are: 1 - bulk ones, of the vein-nested-veinlet ore bodies of stockwork shapes and 2 - small pay streaks of the ore bodies, appeared either in single veins or in the veins, being a part of the wide ore bundles. The example of the first type is the Central ore column of Balei deposit and the column of the Glavnaya (Main) vein of the Karamkenskoe deposit. A deiailed analyses of the graphic material, made by N.V. Petranovskaya for Balei deposit, confirms, that under the bottom of the ore controling vein №2 in the vertical interval from 100 to 250-350 m the rich ores can be prevailed in the zones, which are likely to join with ore bodies of Taseevsky site. The discovery of the new bulk gold ore chimnies is likely to be there. With this, an additional exploration of the south-east flanks of the Balei deposit is needed, that can lead to the discovery of the new bulk gold ore chimnies.


2021 ◽  
pp. 108-116
Author(s):  
VITALY ALEKSEEVICH STEPANOV ◽  
◽  
ANTON VLADIMIROVICH MELNIKOV ◽  

The history of the discovery, development and study of the Kirovskyi gold ore deposit in the Priamur gold-bearing province is considered. The deposit is attributed to the gold-bismuth type of vein deposits of the gold-sulfide-quartz formation. Gold mineralization is genetically related to the formation of the Dzhalinda intrusion of Early Cretaceous granitoids or a series of later dikes of «variegated» composition. The isotopic age of gold mineralization, determined by the Rb-Sr method, is in the fork 131-126 Ma. Further prospects of the deposit are associated with the search for large-volume deposits with stockwork type ore bodies.


2018 ◽  
Vol 482 (4) ◽  
pp. 421-425
Author(s):  
A. Galyamov ◽  
◽  
A. Volkov ◽  
A. Sidorov ◽  
◽  
...  

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