SPATIOTEMPORAL AND GENETIC RELATIONSHIPS OF GOLD ORE AND MERCURY-ANTIMONY MINERALIZATION AT THE HG-SB-GOLD-BEARINGCHAUVAI DEPOSIT (KIRGHIZIA): GEOLOGY, MINERALOGY OF ORES AND FEATURES OF HYDROTHERMAL-METASOMATIC PROCESSES

Author(s):  
A. V. Malyutina ◽  
◽  
Yu. O. Redin ◽  
A. S. Gibsher ◽  
V. P. Mokrushnikov ◽  
...  

The Chauvai Hg-Sb deposit is a striking example of combining two contrasting types of mineralization in space: mercury-antimony and gold ones. The article studies the spatial-temporal and genetic relationships of goldore and mercury-antimony mineralization based on a complex of both traditional geological and mineralogicalgeochemical methods, as well as modern instrumental methods for analyzing the mineral composition. Two types of ores with clear structural confinedness have been found at the deposit: a) mercury-antimonic (cinnabarantimonite) ores, associated with jasperoid breccias and manifested exclusively along the tectonic contact of limestone of the Alai section and terrigenous rocks of the Tolubai Formation, and b) gold- sulphide (arsenopyritepyritic) ores, localized in slightly modified carbonate-terrigenous rocks of the Tolubai Formation, overlying the plane of tectonic contact. Ore formation occurred during the following stages: in the late diagenetic, without interruption passing into the catagenetic-hydrothermal, characterized by the formation of gold mineralization, and then in the later hydrothermal-telethermal, characterized by the development of Hg-Sb mineralization. It is established that the main carrying agent of invisible gold (“invisible gold”) in ores is framboidal and idiomorphic pyrite and, especially, its high-arsenic varieties. A set of conducted studies has shown that the gold ore and mercury-antimony mineralization is broken in time and is genetically associated with various hydrothermalmetasomatic processes, and the Chauvai deposit can be classified as a Carlin-like type.

2021 ◽  
Vol 12 (2) ◽  
pp. 392-408
Author(s):  
Yu. A. Kalinin ◽  
K. R. Kovalev ◽  
A. N. Serdyukov ◽  
A. S. Gladkov ◽  
V. P. Sukhorukov ◽  
...  

We present new age constraints for igneous rocks and ore-metasomatic formations of the gold deposits in the Akzhal-Boko-Ashalin ore zone. In terms of their ore formation, these deposits correspond mainly to the orogenic type, which generally reflects specific metallogeny of the West Kalba gold-bearing belt in East Kazakhstan. Gold-quartz veins and mineralized zones of the gold-sulphide formation are confined to fractures feathering regional NW-striking and sublatitudinal faults. Their common features include the following: gold-bearing veinlet-disseminated pyrite-arsenopyrite ores that are localized in carbonaceous-sandy-schist and turbidite strata of different ages; structural-tectonic control of mineralization, numerous dikes of medium-basic compositions in ore-control zones; and the presence of post-orogenic heterochronous granite-granodiorite rocks, although their relation to gold-ore mineralization is not obvious. Igneous rocks of the study area have similar ages in a narrow range from 309.1±4.1 to 298.7±3.2 Ma, which is generally consistent with the previously determined age of granitoid massifs of gold-ore fields in East Kazakhstan. A younger age (292.9±1.3 to 296.7±1.6 Ma) is estimated for felsic rocks of the dyke complex. For the ore mineralization, the 40Ar/39Ar dating of sericite from near-ore metasomatites yields two age intervals, 300.4±3.4 Ma and 279.8±4.3 Ma. A gap between of the ages of the ore mineralization and the igneous rocks is almost 20 Ma, which may indicate that the processes of ore formation in the ore field continued in an impulse-like pattern for at least 20 Ma. Nevertheless, this confirms a relationship between the hydrothermal activity in the study area and the formation and evolution of silicic igneous rocks of the given age interval, which belong to the Kunush complex, according to previous studies. This interpretation is supported by reconstructed tectonic paleostress fields, showing that directions of the main normal stress axes changed during the ore mineralization stage, which is why the ore bodies significantly differ in their orientations. The above-mentioned data are the first age constraints for the study area. Additional age determinations are needed to further improve understanding of the chronology of ore-forming processes. Actually, all the features characterizing the gold mineralization of the Akzhal, Ashalin and Dauba ore fields, including the data on lithology, stratigraphy, structural tectonics, magmatism, isotope geochronology, mineralogy and geochemistry, can be used as criteria when searching for similar ore fields in East Kazakhstan.


Author(s):  
Х.О. Чотчаев ◽  
Р.Р. Гогичев

В статье приводятся основные рудоконтролирующие факторы, дается оценка металлогенической позиции рудного узла его приуроченностью к над- и околоинтрузивным зонам магматических образований Теплинского комплекса представленного дайками микродиоритов (1 фаза), гранит-порфиров и дацитов (2 фаза), массивами и штоками кварцевых диоритов и гранодиоритов (3 фаза), и многочисленными дайками и штоками андезито-дацитов и риодацитов (4 фаза). Большое разнообразие золоторудных формаций, типов и подтипов объясняется смешанным характером магматических источников золотого оруденения, а также участием в процессе рудообразования тектонических, стратиграфо-литологических, метаморфических факторов. В условиях Теплинского рудного поля в качестве основного поискового метода на жильные и вкрапленные золоторудные скопления рекомендуется геохимическое опробование по первичным и вторичным ореолам Basic ore-controlling factors are given, is given estimation of the metallogenic position of ore formation by its confinement to above- and to near-intrusive zones of the Tepli complex magmatic formation represented by the dikes of microdiorites (1 phase), granite-porphyries and dacite (2 phase), by massifs and by the stocks of quartz it is dioritic and granodiorite (3 phase), and by numerous dikes and by the stocks of andesite-dacite and riodacites (4 phase). The wide variety of gold-ore formations, types and subtypes is explained by the mixed nature of the magmatic sources of gold mineralization, and also by participation in the process of the ore formation of tectonic, stratigrafo-lithologic, metamorphic factors. Under the conditions of Tepli ore field as the basic search method to the vein and sprinkled gold-ore accumulations is recommended geochemical testing on the primary and second halos


2020 ◽  
Vol 26 (10) ◽  
pp. 6-14
Author(s):  
Yu. Pavlenko ◽  

The subject of the research is the methods of forecasting the Eastern Transbaikalia - a large mining region of Russia, in which the main internal and external criteria for ore content are established by modern geological mapping at a scale of 1:1,000,000. The article considers endogenous geochemical criteria for gold concentration in the Earth’s crust of the region, which constitute a mandatory methodological method for predicting gold ore objects at any scale. The aim of the work is to clarify the achieved level of knowledge about the mineralogical and geochemical criteria for gold concentration in the course of the evolution of the Earth’s crust up to the formation of industrial deposits and the isolation of ore formations. The methodology of the study is to systematize a huge amount of factual material concerning the processes of natural concentration of gold, to analyze its representativeness, to assess the completeness and reliability of published and stock information used to clarify the mineralogical and geochemical criteria for predicting ore gold. Using the chemical properties of gold, the forms of finding gold, amount of it in the forming geological complexes and natural environments, their evolution, distribution in structural and tectonic zones, some causes of concentration and mineralogical and geochemical prediction criteria are considered. Special attention is paid to the need to study and account for nanoscale (dispersed) gold. As the main ore-formation units of gold mineralization, standardized ore formations are defined with a division into gold ore proper, complex gold-bearing and gold-bearing and geological and industrial types of deposits. There are 15 geological and industrial types, of which 13 are transbaikal deposits standards and two are attracted from other regions. These types of deposits differ in the number of objects related to them. Due to some similarity in the composition of ore matter, geological and industrial types differ in the most important classification characteristics for the forecast. Areas of distribution of direct and indirect mineralogical and geochemical features grouped into mineralogical and geochemical forecast criteria are promising for endogenous concentration of gold mineralization


Author(s):  
V. Mykhailov ◽  
А. Tots

Tanzania is one of the leading gold mining countries in the world and the discovery of new gold resources on its territory is an actual task. Known gold deposits are concentrated mainly in the northwest of the country, in the metallogenic zone of Lake Victoria, where they are associated with the Archean greenstone belts, and to a lesser extent – in the southwest, in the ore regions of Lupa and Mpanda, confined to the Ubendian Paleoproterozoic mobile belt. With regard to the eastern regions of Tanzania, where the Proterozoic structures of the Uzagaran mobile belt are developed, until recently in this region any significant manifestations of gold mineralization were not known. As a result of our research in the northern part of the Morogoro province of the Republic of Tanzania, a new previously unknown gold deposit Mananila was discovered. It is represented by a large volume, up to 400–450 m long, up to 60–80 m thick, mineralized shear zone over intensely leached and schistosed migmatites, gneisses, amphibolites, penetrated by echelon systems of quartz veins and veinlet, steeply dipping bodies of quartz breccia up to 1.0–1.5 m thick. Gold contents range from 0.61 to 8.11 g/t, the average zone content is 2.5–3.0 g/t. Parallel to the main zone, similar structures are developed on the site, although they are of lower thickness. The forecast resources of the deposit are estimated at 20 tons of gold. 2.8 km to the east from the Mananila field, the recently discovered Mazizi gold deposit is located, and a number of small occurrences of gold are also known in the region. All these objects are located within a large shear zone of the northeastern strike, up to 4–5 km width, over 20 km in length. This serves as the basis for the identification of a new gold ore region in the northern part of the Morogoro province of the United Republic of Tanzania, within the Proterozoic mobile belt of Usagaran, the possible gold content of which has never been previously discussed in geological literature.


1975 ◽  
Vol 17 (10) ◽  
pp. 1121-1127 ◽  
Author(s):  
G.V. Pisemskiy ◽  
S. D. Slier ◽  
T. P. Zhadnova ◽  
L. M. Ganzha ◽  
A. C. Pletnev ◽  
...  

2015 ◽  
Vol 58 (3) ◽  
pp. 180 ◽  
Author(s):  
T. Ya. Malysheva ◽  
R. M. Pavlov ◽  
N. R. Mansurova ◽  
T. V. Detkova

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.


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