Distribution Of Gold Deposits Research Articles

Mapping of geological complexity and analyzing its relationship with the distribution of gold deposits in the Guangxi Gold Ore Province, Southern China

The Guangxi gold ore province contains >370 gold deposits with total resources of >260 t Au. Factor analysis (FA) of geochemical data, and calculation of lineament density within 10 km, 20 km, and 30 km circular search grids across a geological map, were applied in Guangxi to highlight geological complexity and to analyze its relationships with the distribution of gold deposits. The FA of stream sediment geochemical data for 42 elements, subjected first to center logarithmic transformation (clr), yield several element combinations that allowed distinction of metallogenic signatures from geological backgrounds. The element combinations of the first and second factors were Cd–Co–Cr–Cu–Li–Mn–Ni–P–Sb–Y–Zn–Mg and Be–Bi–La–Nb–Pb–Sn–Th–U–W–Zr–Al, and the spatial distributions of their factor scores overlap the Devonian to Permian strata and granite, respectively. The distribution of factor scores of mineralization-related element combination, Ag–As–Au–Mo, coincides with 70 % of gold deposits. The lineament density mapping can highlight different-scale faults and lithological contacts by using circular search grids with different diameters. The C–A fractal modeling for lineament density has indicated four populations, namely low, moderate-low, moderate-high, and high lineament densities. About ∼80 to ∼90 % of the known gold deposits exist in areas with moderate-low to moderate-high lineament densities. This highlights the importance of distinguishing geological complexity based on faults and lithological contacts, which are commonly the pathways for the focused fluid flow and gold ore formation. The deposit-scale geological complexity mapping has predicted several exploration targets, where high-grade gold orebodies have been prospected successfully by drilling in 2018. The geological complexity mapping is a kind of geochemical and geological complementation for resource potential assessment.

Mapping Main Structures and Related Mineralization of the Arabian Shield (Saudi Arabia) Using Sharp Edge Detector of Transformed Gravity Data

Saudi Arabia covers most of the Arabian Peninsula and is characterized by tectonic regimes ranging from Precambrian to Recent. Using gravity data to produce the lateral boundaries of subsurface density bodies, and edge detection of potential field data, a new subsurface structural map was created to decipher the structural framework controls on the distribution of gold deposits in Saudi Arabia. Moreover, we detected the relationships between major structures and mineral accumulations, thereby simultaneously solving the problem of edge detectors over complex tectonic patterns for both deeper and shallower origins. Analytic signal (ASg), theta map (TM), TDX, and softsign function (SF) filters were applied to gravity data of Saudi Arabia. The results unveil low connectivity along the Najd fault system (NFS) with depth, except perhaps for the central zones along each segment. The central zones are the location of significant gold mineralization, i.e., Fawarah, Gariat Avala, Hamdah, and Ghadarah. Moreover, major fault zones parallel to the Red Sea extend northward from the south, and their connectivity increases with depth and controls numerous gold mines, i.e., Jadmah, Wadi Bidah, Mamilah, and Wadi Leif. These fault zones intersect the NFS in the Midyan Terrane at the northern part of the AS, and their conjugation is suggested to be favorable for gold mineralization. The SF maps revealed the boundary between the Arabian Shield and Arabian Shelf, which comprises major shear zones, implying that most known mineralization sites are linked to post-accretionary structures and are not limited to the Najd fault system (NFS).

Research Method for Dyke Swarms Based on UAV Remote Sensing in Desert Areas: A Case Study in Beishan, Gansu, China

The Beishan area of Gansu, China, is an arid desert area, and the surface rocks are well-exposed, creating excellent conditions for drone remote sensing geological mapping experiments. The magmatic rocks and metamorphic rocks in the Beishan area are widely exposed, and a large number of basic and acidic dykes have developed. The formation and distribution of gold deposits are closely related to the dykes. In order to explore the development rules of dykes in this area, a 20km2; area in the Changliushui area of Beishan was selected as the target, and a set of methods for studying the dyke swarm using drones was formed and applied: Images were collected and high-resolution orthophotos and three-dimensional models were synthesized, combined with ground work, and finally remote sensing geological interpretation was performed, to obtain high-precision geological maps. Based on this, the dykes were identified in detail and divided into four phases. The strikes and dips information of the dykes was extracted, and it could be concluded that the dominance of the strikes of the dykes in the target area is NEE, and the inclination is nearly upright, while the length and thickness of dykes obey a skewed distribution. The application of the method not only provides more geological information, but also provides clues for the tectonic evolution and formation mechanisms of dyke swarms, indicates the prospecting direction of future gold deposits.

Examining the controls on gold deposit distribution in the Swayze greenstone belt, Ontario, Canada, using multi-scale methods of spatial data analysis

Understanding the spatial controls on mineral deposits is crucial in mineral exploration targeting. This paper uses a combination of spatial data analysis techniques, such as the distance distribution method, Fry, nearest neighbor index, Ripley’s K-function multi-distance, fractal, and kernel density analysis, to better define controls on the distribution of gold deposits in the Swayze greenstone belt, Ontario, Canada. According to results obtained with the distance distribution method, D2 structures were critical in controlling the spatial distribution of the gold mineralization, with 97% of the gold deposits occurring within 7 km of these structures (and 65% within 4 km). Fry analysis confirmed this spatial relationship with a close agreement between the orientations of the D2 structures and gold deposit alignment. The outcome of Ripley’s K-function cluster analysis suggests that gold deposits occur within 4 km distances of other gold deposits. These findings are consistent with the results from the fractal analysis, showing that gold deposit distribution is bifractal and that different geological features occurred at local (<8 km) versus regional (>8 km) scales. We conclude that higher-order D2 structures and lower-order faults connected to the D2 structures acted as pathways to focus gold-bearing hydrothermal fluids, thus leading to the observed concentration and distribution of gold deposits at the regional to local scales.

Discussion on the Minerogentic Series of Gold Deposit in Qinghai

Gold is one of the most important strategic minerals in Qinghai province. Based on the metallogenic characteristics, types, ore control factors and spatial distribution of gold deposits, the metallogenic regularities of gold deposits were put forward. It’s divided the pre-Cambrian, Early Paleozoic, Late Paleozoic, Mesozoic and Cenozoic the metallogenic series assemblages, and also their distribution features are discussed which focus on five metallogenic periods. According to the theory of metallogenic series of ore deposits, combining with characteristics of typical gold deposits, twenty metallogenic series are preliminarily divided in Qinghai province. It is pointed out some suggestions about prospecting and exploration of gold deposits in Qinghai.

Magmatic control of gold mineralization in Western Primorye (by geophisical data)

An analysis of the regional gravitational field of the north-east of China, Korea and Western Primorye was carried out. The distribution of gold deposits was compared with the development of Mesozoic magmatism and negative anomalies of the gravitational field. Based on the analysis of geological, mineragenic, petrophysical and geophysical materials, geological and geophysical zoning of the western part of the Khanka massif was performed, and a scheme for interpreting geological and geophysical data with elements of minerageny was drawn up. A connection was established between the anomalies of the magnetic and gravitational fields and the position of the supposed gold-bearing ore regions and nodes located in the zone of joints of the North China Triassic-Jurassic volcanic-plutonic belt with the Proterozoic substrates of the Khanka massif. According to geophysical data, Early Jurassic intrusions were identified as, controlling the location of the gold nodes. It was concluded that the gold mineralization is related to the Jurassic magmatism, which increases the prospects for the discovery of gold mineralization in the Khanka district of the Western Primorye.

Magmatic Control of Gold Mineralization in Western Primorye

The article analyzes the regional gravitational field of northeastern China, Korea, and Western Primorye. The distribution of gold deposits is compared with the development of Mesozoic magmatism and negative gravitational field anomalies. Based on an analysis of geological, minerogenic, petrophysical, and geophysical materials, geological and geophysical zoning of the western part of the Khanka massif was carried out and a scheme was compiled for interpreting geological and geophysical data with minerogenic elements. The authors have determined the relationship between magnetic and gravitational field anomalies and the position of prospective gold-bearing ore districts and clusters in the junction zone of the North China Triassic–Jurassic volcanoplutonic belt with Proterozoic substrates of the Khanka massif. Based on geophysical data, early Jurassic intrusions were identified, which controlled the location of gold ore clusters. A conclusion is drawn about the relationship between gold mineralization and Jurassic magmatism, which increases the prospects for discovering gold mineralization in the Prikhankaysky region of Western Primorye.

Geological and isotopic constraints on ore genesis, Huangjindong gold deposit, Jiangnan Orogen, southern China

The Huangjindong gold deposit, with gold resources of ∼80 t, is hosted in Neoproterozoic slates along the Chang-Ping Fault in the Jiangnan Orogen, southern China. The orebodies are dominated by auriferous arsenopyrite-pyrite-quartz-(scheelite) veins; quartz-rich breccias that are cemented by late arsenopyrite, pyrite, muscovite, and quartz; auriferous stibnite-quartz veins; and disseminated gold in arsenopyrite-pyrite-sericite-quartz altered rocks. Neither significant alteration zoning nor ore-element zoning are recognized within the orebodies, although the orebodies at shallower crustal levels are slightly more stibnite-rich. At the regional scale, the first-order control on the distribution of gold deposits is the NNE- to NE-trending crustal-scale, sinistral strike-slip Chang-Ping Fault. As in other gold provinces globally, this controlling fault is not gold mineralized. The gold occurrs in WNW to E-W-trending zones of thrusts and fracture arrays associated with tight ‘locked-up’ asymmetrical folds. The broadly E-W-trending orebodies formed independently within approximately NE-trending fault-bounded corridors defined by the first-order Chang-Ping, and second-order Ni-Wan and Keng-Shang/Chang-Long Faults. Hydrothermal activity was initiated at the ductile-brittle transition, but evolved to brittle-dominated deformation, all within a transpressional environment.Oxygen and hydrogen isotope compositions of fluids (δD = −44.4‰ to −34.2‰; δ18O = +8.6‰ to +9.5‰) calculated from gold-related hydrothermal quartz and hydrothermal sericite, respectively, are consistent with a metamorphic source. Sulfur isotope compositions of the gold-bearing arsenopyrite and pyrite (median values between −8.0‰ and −6.0‰) are generally distinct from δ34S of the regional Neoproterozoic slates in the Jiangnan Orogen, but overlap the compositions of pyrites in global sediment-hosted orogenic gold deposits. Lead isotope compositions of the gold-bearing arsenopyrite and pyrite (206Pb/204Pb: 17.049 to 18.417; 207Pb/204Pb: 15.263 to 15.712; 208Pb/204Pb: 37.597 to 39.220) suggest that the lead was sourced from metamorphic rocks involved in the orogenic events. Therefore, both the stable and radiogenic isotopic data indicate that ore-forming fluids and metals were derived from a metamorphic source, although the precise nature of that source is unclear.On the basis of these geological and isotopic data, Huangjindong is interpreted as an orogenic gold deposit. The gold ore bodies show classic structural controls, being adjacent at the province scale to the crustal-scale Chang-Ping Fault but located in thrusts and associated tight anticlinal fold hinges that lie in corridors between markedly oblique, relatively brittle fault arrays that parallel the Chang-Ping Fault.

Regional structural controls of gold mineralisation, Bendigo and Castlemaine goldfields, Central Victoria, Australia

The Bendigo and Castlemaine goldfields are classic examples of structurally controlled orogenic gold deposits in the Bendigo Zone of central Victoria, SE Australia. Detailed mapping and biostratigraphic interpretation has led to a better understanding of the regional structural controls of this type of gold-quartz mineralisation. Mineralised quartz veins are hosted by the Castlemaine Group, an Early-to-Middle Ordovician turbidite succession at least 3,000 m thick. Gold deposits are controlled by low-displacement faults that are clustered into several belts (the goldfields) indicating a regional structural control. The timing of mineralisation overlapped with that of the major period of deformation including folding, cleavage development and regional faulting. The Bendigo and Castlemaine goldfields are located in an area termed the Whitelaw thrust sheet bounded by two unmineralised, high-displacement, regional-scale faults. Mapping has revealed an interrelationship between the regional-scale faults, regional structural style and goldfield location. The goldfields lie immediately west of the boundary between the upper and lower portions of the thrust sheet and are characterised by symmetric folds with sub-horizontal to synclinal enveloping surfaces, relatively low co-axial strains and moderate cleavage development. The non-gold-bearing areas immediately east of each goldfield correspond with the lower part of the Whitelaw thrust sheet and are characterised by higher non-coaxial strains, stronger cleavage and folds with wide west-dipping limbs giving rise to easterly vergent sections and steeply west-dipping enveloping surfaces. That mineralisation was an integral part of the thin-skinned style of deformation in the central Bendigo Zone is indicated by timing relationships and the interrelationship between local-scale mineralised structures and regional-scale features such as large-displacement unmineralised faults, regional variations in fold style and overall thrust sheet geometry. The work supports previous models that suggest mineralised fluids were focussed along a linked system of deep-seated faults. The primary conduits may have been major regional-scale ‘intrazone’ faults, which are inferred to sole into detachments near the base of the Castlemaine Group. It is proposed that these structures linked with minor intrazone faults and then with networks of low-displacement mineralised faults that were strongly controlled by folds. The location of minor intrazone faults was probably controlled by internal thrust sheet geometry. The distribution of gold deposits and of gold production suggests that maximum fluid flow was concentrated along the eastern margins of networks of low-displacement faults.

Tectonics and distribution of gold deposits in China – an overview

Gold exploration in China has expanded rapidly during the last two decades since a modern approach to economic development has become a national priority. China currently produces 180 tonnes (t) of gold annually, which is still significantly less than South Africa, USA, and Australia. However, China is now recognized as possessing significant gold resources in a wide range of mineral deposit types. Present estimates of gold resources in China exceed 4,500 t, which comprise 60% in gold-only deposits, more than 25% in base metal-rich skarn, porphyry, and vein deposits, and more than 10% in placer accumulations. The major gold provinces in China formed during the main episodes of Phanerozoic tectonism. Such tectonism involved interaction of China's three major Precambrian cratons, North China, Tarim, and Yangtze (or South China when combined with Cathaysia block), with the Angara (or Siberian), Kazakhstan–Kyrgyzstan, and Indian cratons. Resulting collisions included deformation of accreted oceanic sequences between the cratonic blocks. The most important ore-forming orogenies were (1) the late Paleozoic Variscan (405–270 Ma), which led to amalgamation of the Angara, North China and Yangtze cratons, (2) the Indosinian (270–208 Ma), which led to the collision of North China and South China cratons, (3) the Yanshanian (208–90 Ma), which was largely influenced by the subduction of the Izanagi–Pacific plates beneath eastern China, and (4) the Himalayan (<90 Ma) indentation of the Indian continent into Eurasia. No important Precambrian gold systems are recognized in China, mainly because of reworking of exposed Precambrian rocks by these younger orogenies, but there are a few Caledonian (600–405 Ma) gold-bearing systems in northern Xinjiang. Most of China's orogenic, epithermal, and Carlin-like gold deposits are in the reworked margins of major cratonic blocks and in metasedimentary rock-dominated fold belts adjacent to these margins. Accordingly, the major gold provinces are present along the northern, southeastern and southern margins of the North China craton, along the southwestern and northwestern margins of the Yangtze craton, in the Tianshan and Altayshan orogenic belts in northern Xinjiang, and throughout the southeastern China fold belt. Gold-placer deposits derived from these primary deposits are concentrated in the northernmost part of northeastern China and along the northwestern margin of the Yangtze craton. The major provinces with significant gold in porphyry-related copper systems and base metal skarns are present in the Yangtze River area along the northeastern and southeastern margin of the Yangtze craton, in the fold belt in southwestern China, and scattered through northern China. Three-quarters of the Chinese gold-only deposits occur within the North China craton margins. Half are located in the uplifted Precambrian metamorphic rocks and most of the remainder are hosted in the Phanerozoic granitoids that intruded the reworked Precambrian terranes. The abundance of granite-hosted gold contrasts the North China craton with other Precambrian cratons, such as those in Western Australia, central Canada, and Zimbabwe, where gold is mainly hosted in the Archean greenstone belts. This difference may be explained by the multiple episodes of Phanerozoic tectonism along the North China craton margins resulting from the collision of the Angara, North China, and South China cratons, and from subduction of the Izanagi–Pacific oceanic plates underneath the eastern China continent.

Tectonics, granitoids and mesozoic gold deposits in East Shandong, China

Mesozoic granitoids in East Shandong 1 East Shandong gold province is also called Jiaodong gold province, where “Jiao” refers to the Jiaozhou Peninsula, and “dong” stands for east. 1 contain some 30 Moz gold, making East Shandong the largest granitoid-hosted gold province in the world. The gold province is located along the northern boundary of the suture zone between the North China and South China cratons. According to their mineralogical, geochemical and geochronological characteristics, two groups of Mesozoic granitoids are recognised in East Shandong, namely the Middle Yanshanian (MY) (ca. 160–150/130? Ma) and the Late Yanshanian (LY) (ca. 117–85 Ma) granitoids. The first group of granitoids only occur to the north of the suture zone, whereas the second group of granitoids occur on both sides of the suture zone. These characteristics suggest that the two groups of granitoids were associated with different tectonic events. A tectonic analysis suggests that the MY granitoids are the result of collision and suturing of the North and South China cratons during the Triassic to Jurassic, whereas formation of the LY granitoids is attributed to the distal (inland) influence of subduction of the Pacific–Izanagi plate underneath the Eurasian continent during the Cretaceous. The major gold deposits are spatially associated with the MY granitoids in East Shandong. Most of the gold occurs either as quartz-veins in the granitoids or disseminated in altered shear zones along the boundary of the granitoids and Archaean metamorphic rocks. The major gold mineralization and alteration generally display the characteristics of gold-only provinces, namely CO 2-rich, low salinity and reduced fluids and proximal mica and sulfide alteration. These characteristics are different from those of Phanerozoic granitoid-related skarn–porphyry systems. Accordingly, the gold mineralization may be more tectonically and structurally controlled rather than have a direct genetic relationship with the granitoid itself. According to the relationships between tectonics, granitoids, distribution of gold deposits and fluid geochemistry, the major gold in East Shandong may have been formed during the subsequent exhumation stage after the collision of the North and South China cratons.

Type and Distribution of Gold Deposits along the Northern Margin of the North China Craton, People's Republic of China

Gold deposits and prospects are widely distributed along the northern margin of the North China craton. Up to the present, about 900 individual gold deposits, which constitute one of the most important gold metallogenic belts and the second largest gold-producing base in China, have been discovered, explored, and mined. About one-third of China's endogenic gold deposits and 45% of its gold reserve come from this belt, particularly in the Early Precambrian metamorphic terrains. All these gold deposits can be classified into five principal types according to their host rocks: (1) gold-bearing quartz or albite-quartz veins hosted by Archean amphibolite, gneiss, and migmatite; (2) gold-quartz veins hosted by Proterozoic schist, slate, sandstone, and marble; (3) gold deposits hosted by or related to intrusive complexes, including (3a) calc-alkaline granitoids, (3b) alkaline syenite and monzonite, and (3c) ultramafic intrusions; (4) gold deposits occurring in Phanerozoic volcanics; and (5) a group containing placer gold. The tectonic settings, geological features, and temporal and spatial distribution of these different types of gold occurrences indicate that gold mineralization reflects to a great extent the evolution of tectonic environments at the northern margin of the North China craton throughout geological time. Type-1 and -2 deposits generally are hosted by Archean and Proterozoic volcano-sedimentary rocks with variable degrees of metamorphism. The ore-forming materials of these two categories were derived from their wall rocks and were enriched by late metamorphism and magmatism. Types 3 and 4 are recognized in different stages and in various intrusive rocks and volcanics that were formed during Hercynian and Mesozoic Yanshanian orogenies. Gold and base metals were deposited from aqueous fluids with relatively low CO2 content (<20 mol%) and low to moderate salinity (5 to 16 wt% NaCl equiv.) that were related to a mixed fluid of magmatic and meteoric water. Type 5 results from recent weathering of existing gold-bearing volcano-sedimentary, metamorphic, and intrusive rocks as well as gold ores or protores.

Principais domínios metalogenéticos do ouro: representatividade no tempo geológico, sua distribuição espacial e importância econômica

A distribuição dos depósitos de ouro ao longo da coluna geológica do Arqueano ao Recente não é uniforme mas marcadamente assimétrica. Das épocas geológicas da Terra, o Arqueano se constitui no período mais favorável às mineralizações auríferas que se concentraram devido à combinação de eventos tectonometamórficos e ígneos que deram origem aos greenstone belts, podendo ser encontradas em praticamente todas as áreas do planeta. Exemplos na Província Estrutural Superior e Slave no Canadá incluem os distritos auríferos de Porcupine, Kirkland-Larder Lake, Noranda Cadillac-Malartic-Val d'Or, Long Lac, Red Lake e Yellowknife, ao passo que nos escassos terrenos pré-cambrianos dos U .S.A. a mina de Homestake figura como o depósito de ouro mais expressivo. Nos Crátons de Kaapvaal e da Rodésia da África Meridional destacam-se os distritos de Barberton, Steynsdorp e Murchison e diversos outros depósitos no Zimbabwe. Na Austrália Ocidental, encontram-se concentrados preferencialmente nos greenstone belts do Cráton do Yilgarn. Finalmente, na Índia são famosos os distritos auríferos de Kolar que se -situam nos greenstone belts do sistema Dharwar. As mineralizações auríferas do Proterozóico são de pequeno porte e de pouca expressividade econômica (exceto Witwatersrand), reaparecendo de forma conspícua apenas a partir do Mesozóico, com os depósitos mais jovens mostrando um teor mais alto em prata. Exemplos importantes compreendem Mother Lode em rochas jurássicas de Sierra Nevada na Califórnia (U.S.A.) e os depósitos terciários associados a cobre porfirítico (por exemplo Bingham, Utah e vários depósitos ao longo da cadeia Andina), a rochas carbonáticas (por exemplo Carlin, Nevada) e a veios polimetálicos (por exemplo Butte, Montana). O Brasil, de forma análoga a outras áreas arqueanas, tem nos greenstones belts as mais importantes fontes de ouro, quer seja diretamente na sua forma primária (por exemplo Morro Velho, Raposos, Crixás e Andorinhas), ou indiretamente associado aos pláceres atuais (garimpos oriundos da Amazônia Oriental). O Proterozóico brasileiro, em termos de mineralizações auríferas importantes, caracteriza-se principalmente pelos conglomerados do Grupo Jacobina, Formação Moeda e Chapada Diamantina, pela Mina de Passagem no Supergrupo Minas, Serra Pelada na Formação Rio Fresco e a Faixa Weber no Greenstone Belt do Rio Itapicuru (BA). Em qualquer análise metalogenética de uma província aurífera onde se pretende compreender as leis que regem suas mineralizações no espaço e tempo, deve-se levar em conta a existência de uma multitude de metalotectos reveladores, suas diversas combinações e intensidade dos processos, especialmente no caso dos depósitos de ouro em greenstone belts arqueanos.

Lysosomal gold accumulations in pulmonary macrophages.

Although soluble gold has been widely used in the treatment of rheumatoid arthritis, little is known about the distribution of gold deposits in extra-articular tissues. In the synovial lining cells and articular cartilage, the morphology of lysosomes containing gold, the aurosomes, is well documented. Because gold may cause pulmonary injury, the morphology and distribution of gold deposits in pulmonary tissue should be recognized. We found morphologically typical aurosomes with electron-dense membranes and granules, giving the spectrum of gold in electron microprobe analysis, in the interstitial and alveolar macrophages in the open lung biopsies of 3 patients who had received gold treatment but not in 12 patients who had not received gold treatment. In contrast to previous studies, aurosomes were not found in the endothelial cells.

Distribution of Gold Deposits in Alaska

Previous articleNext article FreeDistribution of Gold Deposits in AlaskaGeo. F. BeckerGeo. F. Becker Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 3, Number 8Nov. - Dec., 1895 Article DOIhttps://doi.org/10.1086/607401 Views: 60 PDF download Crossref reports no articles citing this article.