scholarly journals Analysis of the spatial patterns in localization of gold mineralization relative to the system of deep faults in the Chortomlyk greenstone structure of the Ukrainian shield

2019 ◽  
Vol 27 (3) ◽  
pp. 537-545
Author(s):  
I. V. Zhiltsova ◽  
M. V. Ruzina ◽  
M. L. Malova ◽  
N. V. Bilan ◽  
O. A. Tereshkova ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Gold Mineralization ◽  
Spatial Relationship ◽  
Ukrainian Shield ◽  
Sulphide Mineralization ◽  
First Order ◽  
Hydrothermal Mineralization ◽  
Deep Faults ◽  
Localization Conditions ◽  
Gold Bearing

The results of analysisof the patterns of the spatial relationship between hydrothermal gold ore formations and the zones of metasomatites and systems of deep faults within the Chortomlyk greenstone structure of the Middle Pridniprovie megablock in the Ukrainian Shield are given. As a result of studying the localization conditions of gold mineralization, it was established that the gold-bearing mineralization is confined to tectonically fractured zones and is localized among metasomatically altered rocks. The hydrothermal series of metasomatites in the Chortomlyk greenstone structure is represented by greisens, propylites, amphibole-carbonate metasomatites and listvenite-berezites. The mineralization of Au and Mo is associated with metasomatites of the greisen type. The study of spatial relationship between the fields of metasomatites and the gold mineralization and zones of deep faults revealed that the closest relationship is expressed with systems of faults with azimuths of 0° and 270°, 17° and 287°, 77° and 347°. The results of the studies allowed us to develop a newprospecting criterion, which, in turn allows us to state that the gold mineralization within the Chortomlyk greenstone structure is spatially confined to metasomatites related to the schistosity, fracture, millonitization, and cataclase zones with high content of sulphide mineralization. These zones are localized in nodes of intersecting faults of the first order of the system 77° and 347° with discontinuous violations of high orders of azimuths of 0° and 270°, 17°and 287°. The results of the research can be used to develop a set of predictive criteria and the allocation of promising sites of hydrothermal mineralization of gold within the Chortomlyk greenstone structure of the Middle Pridniprovie megablock in the Ukrainian shield.

scholarly journals Molybdenum mineralization of Serhiivka Au-Mo deposit (Middle Dnipro, Ukrainian Shield)

2020 ◽  
pp. 3-11
Author(s):  
V. Sukach ◽  
L. Riazantseva ◽  
V. Somka ◽  
S. Bondarenko
Keyword(s):  
Gold Mineralization ◽  
Ukrainian Shield ◽  
Eastern Flank ◽  
Molybdenum Deposit ◽  
Ore Minerals ◽  
Main Components ◽  
Localization Conditions ◽  
Host Rocks ◽  
Basic Rocks ◽  
First Time

The article is devoted to molybdenum mineralization of the Eastern flank of Au-Mo Serhiivka deposit, located in the Middle Dnipro megablock of the Ukrainian Shield (USh). The generalized description of mineralization is performed on such important questions: discovery and exploration history, structure and composition of the host rocks, metamorphic and metasomatic alteration of rocks, structural position and localization conditions of molybdenum mineralization, ore composition, description of major ore minerals, morphology of mineralization and the most widespread views about its genesis. Molybdenum ores were discovered and named East-Serhiivka occurrence for the first time in 1974, before the discovery of gold mineralization, which occurred in 1985. Serhiivka deposit consists of two Mesoarchaean volcanic-plutonic associations (VPA) of different composition: the early mafic and the late felsic. The Eastern flank of the deposit, where the molybdenum mineralization is concentrated, is a structural knot similar to the lying letter “T”. It is formed by complex joint of the sub-latitudinal Serhiivka and sub-meridional Solone subvolcanic bodies and the East-Serhiivka massif of plagiogranitoids of the late VPA, which intrude basic rocks of early VPA. Molybdenum mineralization is localized in linearly elongated zones with a chaotic network of thin quartz, carbonate-quartz veinlets and poor (2–5 %) sulfide impregnation, including molybdenite. About 20 vein-impregnated ore zones have been recovered with up to 100–150 m thickness and 0,01 to 0,3 %, sometimes more than 1 % average molybdenum grade. The ores are subdivided into two major mineral types: 1) quartz-molybdenite; 2) quartz-sulfide-gold-molybdenite. The main components of ores molybdenite and native gold are associated with pyrite, chalcopyrite, magnetite, occasionally – pyrrhotite, arsenopyrite, scheelite, bismuth telluride, silver and others. Typical non-metallic minerals are quartz, carbonate, feldspar, chlorite, amphibole, biotite, sericite. It is supposed hydrothermal-metamorphogenic genesis of molybdenum (and gold) ores. Molybdenite and gold are rarely detected in the same intersections, which indicates separate genesis of these minerals. According to the accepted classification molybdenum mineralization is systemized as linear stockwork. Molybdenum ores of Serhiivka deposit are mostly considered as independent, separate from gold mineralization, potentially workable mine. It is the most prospective one in the Middle Dnipro region, USh and Ukraine in general. We suggest a comprehensive approach to studying, resource and reserves evaluation of Serhiivka deposit, taking into account the potential of both molybdenum and gold mineralization, as well as concentrations of rhenium and osmium in molybdenite. Geological exploration on the base of this approach will increase investment prospects of Serhiivka gold-molybdenum deposit.

Scarn Gold Mineralization of the Bandurka Ore Occurrences (Ingul Megablock, Ukrainian Shield)

2017 ◽  
Vol 39 (2) ◽  
pp. 8-18
Author(s):  
N. Lyzhachenkо ◽  
◽  
S. Bondarenko ◽  
S. Kurylо ◽  
V. Syоmkа ◽  
...  
Keyword(s):  
Gold Mineralization ◽  
Ukrainian Shield

scholarly journals Re–Os Pyrite Geochronological Evidence of Three Mineralization Styles within the Jinchang Gold Deposit, Yanji–Dongning Metallogenic Belt, Northeast China

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 448 ◽  
Author(s):  
Shun-Da Li ◽  
Zhi-Gao Wang ◽  
Ke-Yong Wang ◽  
Wen-Yan Cai ◽  
Da-Wei Peng ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Northeast China ◽  
Gold Mineralization ◽  
Metallogenic Belt ◽  
Isotopic Analyses ◽  
Mantle Sources ◽  
Stage 1 ◽  
Geochronological Evidence ◽  
Gold Bearing

The Jinchang gold deposit is located in the eastern Yanji–Dongning Metallogenic Belt in Northeast China. The orebodies of the deposit are hosted within granite, diorite, and granodiorite, and are associated with gold-mineralized breccia pipes, disseminated gold in ores, and fault-controlled gold-bearing veins. Three paragenetic stages were identified: (1) early quartz–pyrite–arsenopyrite (stage 1); (2) quartz–pyrite–chalcopyrite (stage 2); and (3) late quartz–pyrite–galena–sphalerite (stage 3). Gold is hosted predominantly within pyrite. Pyrite separated from quartz–pyrite–arsenopyrite cement within the breccia-hosted ores (Py1) yield a Re–Os isochron age of 102.9 ± 2.7 Ma (MSWD = 0.17). Pyrite crystals from the quartz–pyrite–chalcopyrite veinlets (Py2) yield a Re–Os isochron age of 102.0 ± 3.4 Ma (MSWD = 0.2). Pyrite separated from quartz–pyrite–galena–sphalerite veins (Py3) yield a Re–Os isochron age of 100.9 ± 3.1 Ma (MSWD = 0.019). Re–Os isotopic analyses of the three types of auriferous pyrite suggest that gold mineralization in the Jinchang Deposit occurred at 105.6–97.8 Ma (includes uncertainty). The initial 187Os/188Os values of the pyrites range between 0.04 and 0.60, suggesting that Os in the pyrite crystals was derived from both crust and mantle sources.

Predictive geochemistry of ore gold in Eastern Transbaikalia

2020 ◽  
Vol 26 (10) ◽  
pp. 6-14
Author(s):  
Yu. Pavlenko ◽  
Keyword(s):  
Gold Mineralization ◽  
Geological Mapping ◽  
Earth’S Crust ◽  
Natural Environments ◽  
Gold Concentration ◽  
Gold Ore ◽  
Natural Concentration ◽  
Eastern Transbaikalia ◽  
Earth's Crust ◽  
Gold Bearing

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

Gold-bismuth-telluride-sulphide assemblages at the Viceroy Mine, Harare-Bindura-Shamva greenstone belt, Zimbabwe

2008 ◽  
Vol 72 (4) ◽  
pp. 953-970 ◽  
Author(s):  
T. Oberthür ◽  
T. W. Weiser
Keyword(s):  
Native Gold ◽  
Gold Mineralization ◽  
Close Association ◽  
Shear Zones ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Main Stage ◽  
Melting Temperatures ◽  
Native Bismuth ◽  
Gold Bearing

AbstractGold mineralization at the Viceroy Mine is hosted in extensional veins in steep shear zones that transect metabasalts of the Archaean Arcturus Formation. The gold mineralization is generally made up of banded or massive quartz carrying abundant coarse arsenopyrite. However, most striking is a distinct suite of Au-Bi-Te-S minerals, namely joseite-A (Bi4TeS2), joseite-B (Bi4Te2S), hedleyite (Bi7Te3), ikunolite (Bi4S3), ‘protojoseite’ (Bi3TeS), an unnamed mineral (Bi6Te2S), bismuthinite (Bi2S3), native Bi, native gold, maldonite (Au2Bi), and jonassonite (AuBi5S4). The majority of the Bi-Te-S phases is characterized by Bi/(Se+Te) ratios of >1. Accordingly, this assemblage formed at reduced conditions at relatively low fS2 and fTe2. Fluid-inclusion thermometry indicates depositional temperatures of the main stage of mineralization of up to 342°C, in the normal range of mesothermal, orogenic gold deposits worldwide. However, melting temperatures of Au-Bi-Te phases down to at least 235°C (assemblage (Au2Bi + Bi + Bi7Te3)) imply that the Au-Bi-Te phases have been present as liquids or melt droplets. Furthermore, the close association of native gold, native bismuth and other Bi-Te-S phases suggests that gold was scavenged from the hydrothermal fluids by Bi-Te-S liquids or melts. It is concluded that a liquid/melt-collecting mechanism was probably active at Viceroy Mine, where the distinct Au-Bi-Te-S assemblage either formed late as part of the main, arsenopyrite-dominated mineralization, or it represents a different mineralization event, related to rejuvenation of the shear system. In either case, some of the gold may have been extracted from pre-existing, gold-bearing arsenopyrite by Bi-Te-S melts, thus leading to an upgrade of the gold ores at Viceroy. The Au-Bi-Te-S assemblage represents an epithermal-style mineralization overprinted on an otherwise mesothermal (orogenic) gold mineralization.

Mineral Prospectivity Modeling using AVIRIS-NG VNIR-SWIR data and Gravity data for Gold-Sulphide mineralization in parts of GADAG schist belt, Karnataka, India 

2021 ◽  
Author(s):  
Komal Rani
Keyword(s):  
Near Infrared ◽  
Gold Mineralization ◽  
Gravity Data ◽  
Mapping Method ◽  
Schist Belt ◽  
Sulphide Mineralization ◽  
Alteration Zones ◽  
Subsurface Structures ◽  
Present Study Area ◽  
Basement Depth

<p>Gadag schist belt, India is known for sulphide-gold mineralization. In the study area mineralization is controlled structurally and lithologically. In this context, Airborne Visible-Infrared Imaging Spectrometer - Next Generation (AVIRIS-NG) Visible Near InfraRed (VNIR) - Shortwave Infrared (SWIR) bands were utilized to derive alteration zones and structures present in the study area. Lithological boundaries have also been updated using AVIRIS-NG VNIR-SWIR bands derived images enhancement products i.e. Minimum Noise Fraction (MNF) and False Colour Composite (FCC). Further, image spectra of alteration zones (Hydrous mineral etc.) derived from AVIRIS-NG calibrated VNIR-SWIR bands were compared with the standard corresponding reference library spectra (USGS, JPL spectral library). These image spectra have been utilized to demarcate the alteration zones using the Matched Filtering spectral mapping method. Structures were demarcated using high pass (HP) filtered image and FCC images. Low pass (LP) filter image and along with MNF & FCC image composite were utilized to update the lithological boundaries in the study area.</p><p>Ground gravity data has also been processed to derive the subsurface evidences relevant to the deposit in the present study area. Subsurface structures which are responsible for the transportation of mineral rich fluid in the near subsurface are delineated using the gravity data derived products. Apart from this, basement depths are also derived from the gravity data which are being utilized for the validation as well as to further precise the locations of mineral deposits.  These subsurface structures (gravity data), lithology, lineament density and alteration zones are very important evidential layers which have been integrated using fuzzy logic integration techniques to identify potential zones of gold-sulphide mineralization in the present study area. The prospective zones are validated using the secondary data and basement depth derived from the gravity data.</p><p>For similar kind of gold-sulphide mineralization, AVIRIS-NG data and Gravity data can be used to derive the important evidential layers in any part of the world. There are only few studies where such integration approach has been utilized to explore new potential zones of gold sulphide mineralization. </p><p>Keywords: AVIRIS-NG, VNIR-SWIR, alteration, MNF, FCC, Gravity, Basement Depth</p>

Evolutionary-genetic method for forecasting ore gold objects

2020 ◽  
Vol 26 (10) ◽  
pp. 15-27
Author(s):  
Yu. Pavlenko ◽  
◽  
S. Karelin ◽  
Keyword(s):  
Gold Mineralization ◽  
Granite Gneiss ◽  
Gold Content ◽  
Genetic Method ◽  
Geological Processes ◽  
Initial Substrate ◽  
Evolutionary Genetic ◽  
Eastern Transbaikalia ◽  
Reliable Knowledge ◽  
Gold Bearing

The subject of the research is methods for predicting natural heterogeneities containing mineralized areas of the earth’s interior, accumulations of ore gold, which allow obtaining reliable knowledge about a mineral object, applying effective methods for its assessment, study and practical use. The topic of research is an evolutionary-genetic method for predicting ore gold objects, which was used to assess the prospects for gold content in Eastern Transbaikalia on a scale of 1: 500,000 at the beginning of this century. The purpose of the work is to present a new forecasting method, which boils down to identifying geological formations specialized for gold (geoblocks, strata, horizons, zones), and within them - areas of multiple gold concentration. The research methodology consists in identifying the main stages, geological processes leading to the concentration of gold in the process of long-term evolution of natural facies and formations, clarifying the sources of gold and gold-bearing objects in them. As a result of forecasting, it was found that at high initial gold contents in the initial substrate, one or two stages of its mobilization formation and redistribution are sufficient, at low gold contents, multiple redistribution and concentration are required. The likelihood of the industrial and larger-scale gold mineralization is directly correlated with the prospects of geological structures for the localization of endogenous mineralization, conditions that exclude the dispersion of matter in the final phase of ore formation, and the number of concentration stages. The method makes it possible to exclude from the perspective huge areas of the central parts of granite-gneiss domes and granite plutons and requires careful attention to mafic blocks that are not exposed according to geophysical data by erosion, as well as to xenoliths and remnants of potentially gold-bearing host rocks among granitoids

scholarly journals An overview of types and characterization of hot fluids associated with reservoir formation in petroliferous basins

2018 ◽  
Vol 36 (6) ◽  
pp. 1359-1375 ◽  
Author(s):  
Wenxuan Hu ◽  
Xiaolin Wang ◽  
Dongya Zhu ◽  
Donghua You ◽  
Haiguang Wu
Keyword(s):  
Gulf Coast ◽  
Noble Gas ◽  
Close Association ◽  
Eastern China ◽  
Spatial Relationship ◽  
Junggar Basin ◽  
Gas Field ◽  
Isotopic Signatures ◽  
Carbonate Cements ◽  
Deep Faults

Increasing petroleum explorations indicate that the formation of many reservoirs is in close association with deep hot fluids, which can be subdivided into three groups including crust-derived hot fluid, hydrocarbon-related hot fluid, and mantle-derived hot fluid. The crust-derived hot fluid mainly originates from deep old rocks or crystalline basement. It usually has higher temperature than the surrounding rocks and is characterized by hydrothermal mineral assemblages (e.g. fluorite, hydrothermal dolomite, and barite), positive Eu anomaly, low δ18O value, and high 87Sr/86Sr ratio. Cambrian and Ordovician carbonate reservoirs in the central Tarim Basin, northwestern China serve as typical examples. The hydrocarbon-related hot fluid is rich in acidic components formed during the generation of hydrocarbons, such as organic acid and CO2, and has strong ability to dissolve alkaline minerals (e.g. calcite, dolomite, and alkaline feldspar). Extremely 13C-depleted carbonate cements are indicative of the activities of such fluids. The activities of hydrocarbon-related hot fluids are distinct in the Eocene Wilcox Group of the Texas Gulf Coast, and the Permian Lucaogou Formation of the Jimusaer Sag and the Triassic Baikouquan Formation of the Mahu Sag in the Junggar Basin. The mantle-derived hot fluid comes from the upper mantle. The activities of mantle-derived hot fluids are common in the rift basins in eastern China, showing a close spatial relationship with deep faults. This type of hot fluid is characterized by high CO2 content, unique gas compositions, and distinct noble gas isotopic signatures. In the Huangqiao gas field of eastern China, mantle-derived CO2-rich hot fluids have created more pore spaces in the Permian sandstone reservoirs adjacent to deep faults.

scholarly journals LOCALIZATION CONDITIONS AND THE GOLD CONTENT OF THE SCARNS OF ZYGYRKOL ORE ZONE (KABARDINOBALKARSKAYA REPUBLIC)

2017 ◽  
Author(s):  
С.Г. Парада ◽  
В.В. Столяров
Keyword(s):  
Reverse Fault ◽  
Optimum Level ◽  
Gold Content ◽  
Minimum Level ◽  
Lower Section ◽  
The North ◽  
Geological Conditions ◽  
Localization Conditions ◽  
North Western ◽  
Gold Bearing

Охарактеризованы геологические условия локализации золотоносных скарнов Зыгыркольской рудной зоны, выявленных при участии авторов в последние годы на Северном фланге Тырныаузского рудного узла. Установлено длительное (с позднего палеозоя) развитие деформаций в пределах Гитче-Тырныаузского рудного поля, и что к формированию продуктивной на золото Зыгыркольской рудной зоны привели вертикальное растяжение и взбросо-сдвиговые деформации альпийского этапа. Выделены четыре участка развития золотоносных скарнов. Раскрыты характер и степень их золотоносности. Они определяются уровнем денудационного среза Зыгыркольской зоны, которая воздымается в северо-западном направлении под меньшим углом, чем возвышается рельеф, что приводит к уходу под рельеф оптимального рудоносного уровня. Оптимальным уровнем среза обладает Нижний участок, где наиболее золотоносные скарны выходят на земную поверхность. Минимальным уровнем среза обладает Перевальный участок, где продуктивные на золото скарны располагаются на 100?200 м ниже земной поверхности. Are described the geological conditions for localization of the gold-bearing Zygyrkol ore zone scarns, revealed with the participation of the authors in recent years on the northern flank of Tyrnyauz ore unit. Is established the prolonged (from the late Paleozoic period) development of deformations within the limits of Gitche-Tyrnyauz ore field, and that to shaping of productive to gold Zygyrkol ore zone gave vertical tension and the reverse fault-shift deformations of Alpine stage. Four sections of the development of gold-bearing scarns are isolated. Nature and degree of their gold content are opened. They are determined by the level of the Zygyrkol zone denudation shear, which rises up in the North Western direction hearth by smaller angle than is raised relief, which leads to the withdrawal under the relief of optimum ore-bearing level. The lower section, where the gold-bearing scarns leave to the earth’s surface, possesses the optimum level of shear. The crossing section, where the scarns productive to gold are located on 100?200 m lower than earth’s surface, possesses the minimum level of shear.

scholarly journals Role of the Environment in the Placement of Apocarbonate Gold Mineralization Chakylkalyan Megablock (Southern Uzbekistan)

2021 ◽  
Vol 7 (6) ◽  
Author(s):  
T. Yarboboev ◽  
Sh. Sultanov ◽  
I. Ochilov
Keyword(s):  
Carbonate Rocks ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Gold Deposition ◽  
Sufficient Detail ◽  
Available Information ◽  
Gold Bearing ◽  
Geochemical Specialization

Analysis of the available information and the results of many years of research on gold deposits in Uzbekistan made it possible to identify the main unconventional types of deposits. Among them, the most interesting are apocarbonate, crustal, sulfide-carbonaceous and apovolcanogenic quartzite (Upper-Kattakashkasai ore occurrence). The apocarbonate type is widespread in Uzbekistan, has been studied in sufficient detail and information is provided on it in this article. The article examines the existence, distribution and genesis of ores of Karlin type gold deposits. The generalizing characteristics of the Karlin type gold mineralization are given. The issues of geochemical specialization of the Paleozoic strata of the Chakylkalyan megablock are considered, the most favorable stratolevel for the localization of mineralized zones is determined, and the features of carbonate rocks in the process of gold deposition during reactions with silicic solutions are characterized. Based on the materials of regional geochemical profiling, the behavior of the main ore-forming elements in the rocks of both carbonate and volcanogenic-terrigenous strata is analyzed. As a result of the analysis, subclarkic contents of the main ore-forming elements (As, Co, Ni, Pb, Cu, Ag, V, Cr, Sc) were revealed, which create increased concentrations in gold-bearing pyrites of both apocarbonate gold mineralization and related formations.

Sign in / Sign up

Export Citation Format

Share Document