The Geochemical Features of Epithermal Gold-Telluride (Au-Te) Ores of the Podgolechnoe Deposit (Central Aldan Ore District, Yakutia)

2017 ◽  
Vol 743 ◽  
pp. 422-425 ◽  
Author(s):  
Yackov Yur’evich Bushuev ◽  
Vasilii Ivanovich Leontev
Keyword(s):  
Sedimentary Cover ◽  
Ore Deposits ◽  
Crystalline Basement ◽  
Alkaline Magmatism ◽  
Epithermal Gold ◽  
Geochemical Composition ◽  
Gold Ores ◽  
Gold Ore ◽  
Gold Telluride ◽  
Ore District

The Central Aldan ore district is a geologically unique area, representing the conjunction zone of the ancient structures of the Archean–Proterozoic crystalline shield, overlain by the Vendian–Cambrian sedimentary cover. The latter was formed in the Mesozoic by intensive alkaline magmatism. Within the Central Aldan ore district, most of primary gold-ore deposits are confined to the sedimentary cover. Until recently it was considered that only ancient complexes in the crystalline basement contain commercial Au-U mineralization. As a result of the geological exploration works over the period of 2003–2006, the Podgolechnoe deposit was discovered. Gold mineralization in this deposit occurs both in rocks of sedimentary cover and crystalline basement. Ore bodies in rocks of the crystalline basement (A-type alkaline deposits) contain epithermal gold-telluride (Au-Te) mineralization, which is new for Central Aldan ore district. This work presents results of the study of geochemical composition of the Podgolechnoe deposit ores and their comparison with typical epithermal gold-ore deposits. In total, 15 samples were studied. The homogeneity of the sample collection, the correlation between Au and other elements, the enrichment coefficients of elements-admixtures, and the REE distribution were analyzed. It was established that gold ores of the Podgolechnoe deposit are geochemically heterogeneous, but, in general, they correspond to the geochemical spectrum characteristic of the gold ores of A-type epithermal deposits. In contrast to Au-U deposits, common in the studied area, ores of the Podgolechnoe deposit show no correlation between gold and uranium.

Ore Mineralization in Adular-Fluorite Metasomatites: Evidence of the Podgolechnoe Alkalic-Type Epithermal Gold Deposit (Central Aldan Ore District, Russia)

2017 ◽  
Vol 743 ◽  
pp. 417-421 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Yackov Yur’evich Bushuev
Keyword(s):  
Ore Deposits ◽  
Epithermal Gold ◽  
Gold Ore ◽  
Ore Bodies ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Ore Deposit ◽  
Host Rocks ◽  
Ore District

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.

Geochemical Features of Au-Te Epithermal Ores of the Samolazovskoye Deposit (Central Aldan Ore District, Yakutia)

2018 ◽  
Vol 769 ◽  
pp. 207-212 ◽  
Author(s):  
Yackov Yur’evich Bushuev ◽  
Vasilii Ivanovich Leontev ◽  
Maria M. Machevariani
Keyword(s):  
Lower Cambrian ◽  
Crystalline Basement ◽  
Granitic Gneiss ◽  
Gold Telluride ◽  
Ore Bodies ◽  
Geochemical Study ◽  
Order Of Magnitude ◽  
Archean Basement ◽  
Epithermal Au ◽  
Ore District

The Samolazovskoye deposit (Central Aldan ore region, Russia) is confined to the porphyry syenite lopolith (J3-K1), localized between the granitic gneiss Archean basement and the series of the Vendian-Lower Cambrian carbonate cover rocks. Four hydrothermal-metasomatic parageneses have been identified within the deposit: skarn paragenesis, developed on the syenites and carbonate cover rocks contact; so called «gumbaite» paragenesis (kalifeldspar + fluorite + carbonate ± quartz), superimposed on the intrusive massif rocks; feldspatholitic paragenesis (quartz + feldspar), developed in the granitic gneisses of the crystalline basement; ore-bearing fluorite-roscoelite-carbonate-quartz paragenesis, superimposed on all of the above. The article compares ores evolved within gumbaitic syenites, basement feldspatholites and breccias, composed of all the above-mentioned rocks clasts. The geochemical study of given ores, resulted in two identified elements associations: gold-telluride (Au, Sb, As, V, Tl, Te, Hg, W) related to the fluorite-roscoelite-carbonate-quartz hydrothermal-metasomatic paragenesis and (uranium)-polymetallic (Bi, Cu, Pb, Zn, Mo, Se, Li, U), associated with the syenites gumbaitization (?). There is only gold-telluride association within the basement ore bodies, while the ore bodies localized in the syenites intrusion hold both associations, along with the Au and Ag contents being an order of magnitude higher. Breccia ores are characterized by the maximum concentrations of the ore elements. Gold-telluride association of the Samoazovsky deposit ores is specific to epithermal Au-Te mineralization associated with alkaline (A-type) magmatism.

scholarly journals Localisation of gold ores in faults of different types

2020 ◽  
pp. 33-43
Author(s):  
E. M. Nekrasov
Keyword(s):  
Fault Zones ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Gold Ores ◽  
Gold Ore ◽  
North East ◽  
Ore Bodies ◽  
Different Types ◽  
Local Shift ◽  
Gold Bearing

The results of the author’s and general works of domestic and foreign geologists, who studied the location of the largest gold deposits in fault zones, characterised by the structure of ore-bearing zones and the concentration of reserves of ores and gold of different scale in them, are presented. The main reasons for such differences are considered. The longest faults on our planet are regional shifts. They are continuously traced for hundreds (up to 1,400) of kilometres along the boundaries of gold-bearing belts and provinces. However, gold ore deposits are located in their zones at extremely limited (point) intervals not exceeding 3—5 km. They are always enclosed between ancient transverse or oblique-oriented fractures of deep, most likely mantle, formation and penetration. In all mineralised faults, gold ore bodies are localised in various geological and structural traps, which are considered in the article and are reflected in the plans and sections. The crossing nodes of regional shifts, as well as overfaults and faults of transverse faults (and dislocations), act as the main promising objects in the deposits search and exploration. Obviously, such nodes should be considered as direct signs of the possible evidence of gold ores. The internal structure of the world leader, gold-bearing Muruntaussky (North-East) local shift (Uzbekistan), studied in detail by the author and other geologists, is given as an example.

scholarly journals Constraints of nonseismic geophysical data on the deep geological structure of the Benxi iron-ore district, Liaoning, China

2020 ◽  
Vol 12 (1) ◽  
pp. 887-903
Author(s):  
Chun-Hui Xu ◽  
Lin-Fu Xue ◽  
Chong Peng
Keyword(s):  
Iron Ore ◽  
Sedimentary Cover ◽  
Geological Structure ◽  
Ore Deposits ◽  
Geophysical Data ◽  
Liaoning Province ◽  
Magnetotelluric Data ◽  
Iron Ore Deposits ◽  
Iron Bearing ◽  
Ore District

AbstractThe Benxi area in Liaoning Province is one of the most important iron-ore districts in China. This study uses nonseismic geophysical data (in the form of gravity–magnetic–magnetotelluric data) and based on the section modeling method to model the deep, three-dimensional geological structure of the Benxi area. Based on the modeling results and deep geological structure characteristics, the Benxi area can be divided into three first-order deep geological tectonic units. A close relationship is between tectonic unit and iron-ore concentrations. First, high-quality iron-ore deposits occur within the tectonic boundary and sedimentary boundary zone of the Jiao–Liao–Ji Belt, reflects the protective effect of sedimentary cover on the iron-bearing formation. Second, enriched iron-ore deposits are mainly developed in Mesozoic granitic intrusion zone, reflects the hydrothermal leaching of silicon in host iron-bearing formations during magma intrusion. Thus, the findings of this study have important implications for future prospecting in the Benxi iron-ore district.

Ore Mineralization of the Epithermal Samolazovskoe Gold-Ore Deposit, Aldan Shield (Russia)

2018 ◽  
Vol 769 ◽  
pp. 213-219 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Konstantin Chernigovtsev
Keyword(s):  
Aldan Shield ◽  
Crystalline Basement ◽  
Linear Type ◽  
Ore Deposit ◽  
Gold Ore ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Ore Deposit ◽  
Full Volume ◽  
Ore District

The Samolazovskoe gold-ore deposit is located in the Central Aldan ore district (Russia) within the Yukhta multiphase volcano-plutonic massif, consisted of rocks of the monzonite-syenite formation (J3–K1). Four hydrothermal-metasomatic mineral parageneses are distinguished in the deposit: skarn, developed at the contact of syenites and rocks of the carbonate cover (V–Є); gumbeite, superimposed on the rocks of the intrusive massif; feldspatholite, developed in granite gneisses of the crystalline basement (PR) at their contact with the intrusive massif; ore-bearing fluorite–roscoelite–carbonate–quartz, superimposed on all above-mentioned types of mineralization. The main types of mineralization in the Samolazovskoe deposit are the following: (1) vein-disseminated linear type (now recovered in full volume); (2) vein-disseminated stockwork type; and (3) breccia-like type. Vein-filling minerals of the ores are quartz, fluorite, roscoelite, and carbonate. The main ore minerals are pyrite and marcasite; the secondary ones are bournonite, fahlore, sphalerite, galena, and chalcopyrite. Coloradoite and calaverite are less common; native gold occurs very rarely. Pyrite and marcasite are characterized by the following impurities (wt%): Sb (0.64–1.90), As (0.94–5.25), Te (1.02–3.82), and V ( 0.21–0.31).

Spatial Relations of Gold Ore Deposits and Cretaceous Granitoids of Chukotka

2018 ◽  
Vol 482 (4) ◽  
pp. 421-425
Author(s):  
A. Galyamov ◽  
◽  
A. Volkov ◽  
A. Sidorov ◽  
◽  
...  
Keyword(s):  
Spatial Relations ◽  
Ore Deposits ◽  
Gold Ore

Tracing the SW border of the Svecofennian Domain in the Baltic Sea region: evidence from petrology and geochronology from a granodioritic migmatite

2021 ◽  
Author(s):  
Evgenia Salin ◽  
Jeremy Woodard ◽  
Krister Sundblad
Keyword(s):  
Baltic Sea ◽  
Short Distance ◽  
Sedimentary Cover ◽  
Crystalline Basement ◽  
Drill Core ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
Drill Site ◽  
Southwestern Margin ◽  
The Baltic

AbstractGeological investigations of a part of the crystalline basement in the Baltic Sea have been performed on a drill core collected from the depth of 1092–1093 m beneath the Phanerozoic sedimentary cover offshore the Latvian/Lithuanian border. The sample was analyzed for geochemistry and dated with the SIMS U–Pb zircon method. Inherited zircon cores from this migmatized granodioritic orthogneiss have an age of 1854 ± 15 Ma. Its chemical composition and age are correlated with the oldest generation of granitoids of the Transscandinavian Igneous Belt (TIB), which occur along the southwestern margin of the Svecofennian Domain in the Fennoscandian Shield and beneath the Phanerozoic sedimentary cover on southern Gotland and in northwestern Lithuania. It is suggested that the southwestern border of the Svecofennian Domain is located at a short distance to the SW of the investigated drill site. The majority of the zircon population shows that migmatization occurred at 1812 ± 5 Ma, with possible evidence of disturbance during the Sveconorwegian orogeny.

Application of high resolution airborne geophysics to epithermal gold exploration in Northeast Queensland and Coromandel, New Zealand

1989 ◽  
Vol 20 (2) ◽  
pp. 99 ◽  
Author(s):  
S.S. Webster ◽  
R.W. Henley
Keyword(s):  
High Resolution ◽  
Regional Scale ◽  
Cost Effective ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Magnetic Data ◽  
Mapping Technique ◽  
Epithermal Gold ◽  
Airborne Geophysics ◽  
Airborne Geophysical Data

High resolution airborne geophysical data over broad areas have been found to optimize exploration for epithermal gold deposits in differing geological environments.Genetic exploration models may be tested in favourable sites by the recognition of geophysical signatures. These signatures reflect structural, lithological and alteration patterns arising from controls on ore deposits and can be applied at regional or detailed scales, using the same data set.At regional scale (e.g. 1:100,000) the magnetic data reflect the regional tectonics and divide the area into domains for the application of appropriate genetic models. At prospect scale (e.g. 1:25,000) the radiometric data allow the extrapolation of poorly outcropping geology to provide a cost-effective mapping technique. The magnetic data can be used to supplement this interpretation or can be used to target deeper sources for direct investigation by drilling.

Types, structure and location of fractured gold pockets

2021 ◽  
pp. 62-75
Author(s):  
Evgeny Nekrasov ◽  
Alexander Nekrasov
Keyword(s):  
Baikal Region ◽  
Western Siberia ◽  
South Urals ◽  
High Grade ◽  
Gold Ores ◽  
Gold Ore

Fractured gold ore pockets of various types are classified and their structure is described in detail. This will allow explorationists to confirm high-grade gold ores, which is especially important in underground deposit mining. Gold pockets were mapped and analyzed by the author at deposits in Uzbekistan (Muruntau, Daugyz, Charmitan, Kokpatas), eastern Trans-Baikal region (Darasun, Balei, etc.) and Kochkarskoye (South Urals). Also, the paper describes the material collected by the author at gold pockets in Natalkinskoye, Nezhdaninskoye, Pavlik and Kyuchus deposits in Yakutia, Berikul in Western Siberia, Bakyrchik in Kazakhstan as well as deposits from Australia (Kalgoorlie, Northman, etc.), USA (Comstock, etc.), Canada (Porcupine), among others.

scholarly journals Influence of basement rocks on fluid evolution during multiphase deformation: the example of the Estamariu thrust in the Pyrenean Axial Zone

2020 ◽  
Author(s):  
Daniel Muñoz-López ◽  
Gemma Alías ◽  
David Cruset ◽  
Irene Cantarero ◽  
Cédric M. Jonh ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
Crystalline Basement ◽  
Normal Faults ◽  
Published Data ◽  
Fluid Migration ◽  
Rock Interaction ◽  
Fluid Chemistry ◽  
Vein Formation ◽  
Basement Rocks ◽  
Calcite Veins

Abstract. Calcite veins precipitated in the Estamariu thrust during two tectonic events decipher the temporal and spatial relationships between deformation and fluid migration in a long-lived thrust and determine the influence of basement rocks on the fluid chemistry during deformation. Structural and petrological observations constrain the timing of fluid migration and vein formation, whilst geochemical analyses (δ13C, δ18O, 87Sr/86Sr, clumped isotope thermometry and elemental composition) of the related calcite cements and host rocks indicate the fluid origin, pathways and extent of fluid-rock interaction. The first tectonic event, recorded by calcite cements Cc1a and Cc2, is related to the Alpine reactivation of the Estamariu thrust, and is characterized by the migration of meteoric fluids, heated at depth (temperatures between 56 and 98 °C) and interacted with crystalline basement rocks before upflowing through the thrust zone. During the Neogene extension, the Estamariu thrust was reactivated and normal faults and shear fractures with calcite cements Cc3, Cc4 and Cc5 developed. Cc3 and Cc4 precipitated from hydrothermal fluids (temperatures between 127 and 208 °C and between 102 and 167 °C, respectively) derived from crystalline basement rocks and expelled through fault zones during deformation. Cc5 precipitated from low temperature meteoric waters percolating from the surface through small shear fractures. The comparison between our results and already published data in other structures from the Pyrenees suggests that regardless of the origin of the fluids and the tectonic context, basement rocks have a significant influence on the fluid chemistry, particularly on the 87Sr/86Sr ratio. Accordingly, the cements precipitated from fluids interacted with crystalline basement rocks have significantly higher 87Sr/86Sr ratios (> 0.710) with respect to those precipitated from fluids that have interacted with the sedimentary cover (

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