Native gold from the Inagli Pt–Au placer deposit (the Aldan Shield, Russia): geochemical characteristics and implications for possible bedrock sources

2017 ◽  
Vol 53 (3) ◽  
pp. 323-338 ◽  
Author(s):  
Tatyana V. Svetlitskaya ◽  
Peter A. Nevolko ◽  
Vladislav V. Kolpakov ◽  
Nadezhda D. Tolstykh
Keyword(s):  
Native Gold ◽  
Aldan Shield ◽  
Placer Deposit ◽  
Geochemical Characteristics

scholarly journals Mineralogical and Geochemical Features of Native Gold From Placers of the Evota Gold-Bearing Region (Russia, Aldan Shield)

2021 ◽  
Vol 906 (1) ◽  
pp. 012116
Author(s):  
Anatolii Zhuravlev ◽  
Zinaida Nikiforova ◽  
Aleksey Ivanov ◽  
Michil Ivanov
Keyword(s):  
Native Gold ◽  
Aldan Shield ◽  
Potassium Feldspar ◽  
Primary Sources ◽  
Alkaline Magmatism ◽  
High Grade ◽  
Alluvial Deposits ◽  
Ore Mineralization ◽  
Very High ◽  
Gold Bearing

Abstract Evota gold-bearing region is located in south of Republic Sakha (Yakutia) within the Nimnyr terrane of Aldan shield. A large numbers of gold-bearing placers are known on studied territory, but the primary sources for them have not been established. In this work, based on the study of the mineralogical and geochemical features of gold from alluvial deposits of the Evota gold-bearing region, possible genetic types of primary sources are considered. Obtained data showed that native gold in the studied objects has a very high, high and medium fineness. The roundness of gold is different. Almost ore crystals with sharp edges and well-rounded individuals with polished faces were found. The fineness of the studied gold grains was determined by microprobe analyzer Cameca Camebax-micro and varies in the range from 812 to 1000 %⁰. A thin (up to 20 μm) high-grade rim was found in two grains (cr. Zolotoy). The central part of one of them has a fineness of 865 %o, and in the edge part it reaches 1000 %⁰, which indicates that this gold was in the hypergenesis zone. Admixture elements determined as traces and are presented Cu, Pd, Fe, Ni. Minerals-microinclusions - quartz, potassium feldspar, pyroxene, staurolite, maldonite, bismuthite revealed in gold grains. In some watercourses, for example, in the creek Sukhoi, only very high fineness gold (993-1000 %⁰) was found. The presence of high-grade gold (cr. Sukhoi), intergrowths of gold with bismuthite (cr. Zolotoy), as well as inclusions of maldonite (cr. Yagodny) gives opportunity for assuming that primary sources could be basic ores such presented in the P. Pinigin deposit. At the sites (cr. Elovyi, r. Evota), both medium-grade and very high-grade gold were found, the fineness range varied from 827 to 998 %⁰. The presence of gold with medium fineness and good roundness in studied watercourses probably indicates an additional supply of gold from primary sources formed as a result of the alkaline magmatism development of the Mesozoic age. Thus, for gold with high and very high fineness by admixture-elements, chemical composition and microinclusions, a genetic relationship with primary sources similar to the P. Pinigin deposit was found; for gold grains with medium fineness, formation in gold-ore mineralization characterized for the Mesozoic stage ore development such in deposits of Central-Aldan ore region is assumed.

scholarly journals Types of Tellurium Mineralization of Gold Deposits of the Aldan Shield (Southern Yakutia, Russia)

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 698
Author(s):  
Larisa A. Kondratieva ◽  
Galina S. Anisimova ◽  
Veronika N. Kardashevskaia
Keyword(s):  
Large Scale ◽  
Native Gold ◽  
Gold Mineralization ◽  
Aldan Shield ◽  
Original Data ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Gold Content ◽  
Southern Yakutia ◽  
Igneous Activity

The published and original data on the tellurium mineralization of gold ore deposits of the Aldan Shield are systematized and generalized. The gold content is related to hydrothermal-metasomatic processes caused by Mesozoic igneous activity of the region. The formation of tellurides occurred at the very late stages of the generation of gold mineralization of all existing types of metasomatic formations. 29 tellurium minerals, including 16 tellurides, 5 sulfotellurides and 8 tellurates have been identified. Tellurium minerals of two systems predominate: Au-Bi-Te and Au-Ag-Te. Gold is not only in an invisible state in sulfides and in the form of native gold of different fineness, but also is part of a variety of compounds: montbrayite, calaverite, sylvanite, krennerite and petzite. In the gold deposits of the Aldan Shield, three mineral types are distinguished: Au-Ag-Te, Au-Bi-Te, and also a mixed one, which combines the mineralization of both systems. The decrease in the fineness of native gold is consistent with the sequence and temperatures of the formation of Te minerals and associated mineral paragenesis from the epithermal–mesothermal Au-Bi-Te to epithermal Au-Ag-Te. The conducted studies allowed us to determine a wide variety of mineral species and significantly expand the area of distribution of Au-Te mineralization that indicates its large-scale regional occurrence in the Aldan Shield.

GEOCHEMICAL CHARACTERISTICS OF ILMENITE SANDS OF CHHATRAPUR BEACH PLACER DEPOSIT OF ORISSA, INDIA: A PIXE STUDY

2003 ◽  
Vol 13 (03n04) ◽  
pp. 121-131 ◽  
Author(s):  
A. K. MOHANTY ◽  
V. VIJAYAN ◽  
D. SENGUPTA ◽  
S. K. DAS ◽  
S. K. SAHA
Keyword(s):  
Ferrous Iron ◽  
Placer Deposit ◽  
Geochemical Characteristics ◽  
Heavy Mineral ◽  
Source Rocks ◽  
Eastern Ghats ◽  
Major Constituent ◽  
Metamorphic Rocks ◽  
Mineral Assemblages ◽  
Principal Source

Geochemical characteristics of detrital ilmenites of Chhatrapur beach placer deposit studied by PIXE and EDXRF methods. Ilmenite occurs as the major constituent of the heavy mineral assemblages. The detrital ilmenite contains TiO 2 52.52 - 56.85 wt%, FeO 1, (total Fe ) 38.36 - 42.28 wt%, in addition to trace amounts of Al , Mg , Si , Ca , V , Cr , Mn , Cu and Zn . The khondalite-charnockite suites of Eastern Ghats Group of rocks were important source rocks for the ilmenite bearing heavy mineral sands. Based on TiO 2 concentration in the detrital ilmenite grains, which suggests that the principal source rocks were high grade metamorphic rocks. Ti /( Ti + Fe ) ratio in the ilmenite varied from 0.50 to 0.52, which indicates slight oxidation. FeO/Fe 2 O 3 ratio (3.20) in the concentrates indicates that around one third of the ferrous iron content of the ilmenites has been oxidized by weathering.

Significance of Mineralogical and Lithologic-Petrographical Rank in the Ranking of Geological Information

2020 ◽  
Vol 42 (4) ◽  
pp. 33-49
Author(s):  
O.V. CHEPIZHKO ◽  
V.V. YANKO ◽  
V.M. KADURIN ◽  
I.M. NAUMKO ◽  
S.M. SHATALIN
Keyword(s):  
Fluid Flow ◽  
Black Sea ◽  
Bottom Sediments ◽  
Oil And Gas ◽  
Sedimentary Cover ◽  
Geochemical Characteristics ◽  
The Black Sea ◽  
Flow Parameters ◽  
Geochemical Parameters ◽  
Geological Information

For the first time the importance of mineralogical and lithological-petrographical ranks in the line of geological information ranks is substantiated for implementation of long-term forecasts, standard and non-standard approaches to research of physical and geochemical parameters as a basis of creation of complex system of forecast criteria and prospecting indicators of hydrocarbons within the sedimentary cover of Black sea based on the theory of global fluid-flows derivation. These criteria have different sensitivity to the object (hydrocarbon deposits) and are therefore ranked. The ranking determined the following parameters: 1) seismic data within the object, obtained by the method of deep seismic sounding, RWM SDP; 2) parameters of tectono-geodynamic structures; 3) the main characteristics of sedimentary cover and bedrock; 4) geochemical characteristics; 5) parameters of mineral complexes and fluid inclusions in mineral neoformations; 6) the value of the distribution of meiobenthos. Based on modern views of oil and gas geology, structural-tectonic and lithological-facies criteria are among the main ones. The study of the mineralogical component of sediments is made with using mineralogical, thermobarogeochemical and X-ray spectral methods. Fixation of anomalies of fluid flow at the bottom of the Black Sea as to the distribution of abiotic parameters in order to assess the prospects of oil and gas is determined by structural and tectonic features and high permeability of fluid flow; parameters of mineral complexes (minerals, facies) and genetic connections; heterogeneity of geochemical characteristics of bottom sediments; the presence of hydrocarbon inclusions in authigenic minerals of bottom sediments.

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