scholarly journals TOURMALINE MINERALIZATION IN CARBONACEOUS SHALE OF THE BAIKAL DEPOSIT (SOUTH URAL)

Author(s):  
A.V. Snachev ◽  
◽  
A.V. Kolomoets ◽  
M.A. Rassomakhin ◽  
V.I. Snachev ◽  
...  

The article discusses the geological structure of the Baikal deposit, located within the Kumak ore field and confined to the black shale of the Bredy Formation (C1bd). It has been established that the gold mineralization within the occurrence is confined mainly to the members of quartz-mica-tourmaline metasomatically altered carbonaceous shales. Gold is noted here in intergrowth with tourmaline. In terms of their chemical composition, tourmalines belong to dravite and foitite and are close to those of orogenic gold and gold-sulfide deposits. The close intergrowth of thin needle- like tourmaline and gold indicates the synchrony of their formation and allows the manifestation of Baikal deposit to be attributed to the quartz-tourmaline formation.

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.


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


LITOSFERA ◽  
2019 ◽  
pp. 111-138
Author(s):  
I. Yu. Melekestseva ◽  
V. V. Zaykov ◽  
G. A. Tret’yakov ◽  
K. A. Filippova ◽  
V. A. Kotlyarov

Subject. The article presents the results of study of Mechnikovskoe gold deposit associated with listvenites and beresites of the Miass region of the Southern Urals.Materials and methods. Materials were sampled during the field work of 2010– 2012. The chemical composition of rocks is analyzed by methods of classical chemistry (rock-forming oxides) and ICP MS (trace elements). The mineral composition is determined on an electron microscope with EDS.Results. The deposit is composed of tectonic sheets of serpentinites, carbonatized serpentinites and listvenites (sheet I), metadiabases and plagioclase metabasalts of the Irendyk Formation and beresites and volcanosedimentary rocks and metabasalts of the Karamalytash Formation (sheet II). In the central part of the deposit, the volcanic rocks are intruded by a dike of finegrained island-arc granites. Chromites of serpentinites are characterized (on average) by high Cr# (89) and low Mg# (29) values and low contents of Al2O3 (6.94 wt %) and MgO (5.5 wt %). Gold-bearing rocks include listvenites, beresites and carbonaceous shales. The major ore mineral is pyrite; accessory minerals are Au and Ag minerals, chalcopyrite, fahlores, galena, sphalerite, pyrrhotite, cubanite, vaesite, melonite, secondary copper sulfides, barite, rutile, monazite and xenotime. Gold of the deposit contains low Ag contents (3.52 wt %) and minor amount of Cu and Hg (<1 wt % in most analyses).Conclusions. The listvenites and beresites of the deposit were formed after ultramafic and mafic rocks, respectively. The discovery of gold in various rocks indicates that gold mineralization was deposited after the formation of the geological structure of the deposit. The source of gold was most likely related to a magmatic fluid.


2019 ◽  
Vol 75 ◽  
pp. 184-217 ◽  
Author(s):  
Basem A. Zoheir ◽  
Peter R. Johnson ◽  
Richard J. Goldfarb ◽  
Dietrich D. Klemm

2021 ◽  
pp. 4-18
Author(s):  
ANATOLY IVANOV ◽  
YURI AGEEV ◽  
ALEXANDER MEZENTSEV ◽  
BASIL MOLOCHNY ◽  
VICTOR KONKIN

New data is provided on gold mineralization in the southern Baikal-Patom metallogenic province, Ikibzyakskoye ore field, located in Pravo-Mamakansky deep fault zone separating Patom fold area from Baikal-Vitim volcanic-plutonic belt. For the first time, the metallogenic province was found to comprise granitoid-hosted ore vein-stringer zones with high-grade economic gold sulfide-quartz mineralization. This mineralization is localized within fault shistosity zones manifesting intense beresitization and listvenitization (in metabasite xenoliths).


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