Hydrothermal Gold Mineralization at the Rodnikovoe Deposit in South Kamchatka, Russia
Reads0
Chats0
TLDR
The Rodnikovoe gold mine in southern Kamchatka as mentioned in this paper was the first known gold mine to be mined using the K-Ar method, and the age of the mine was estimated to be 0.9 to 1.1 Ma.Abstract:
. The Rodnikovoe gold deposit situated in a presently active hydrothermal system located north of the Mutnovsko-Asachinskaya geothermal area in southern Kamchatka, Far Eastern Russia, consists of typical low-sulfidation quartz-adularia veins in a host rock of diorite. The age of the mineralization was dated by the K-Ar method as 0.9 to 1.1 Ma based on adular-ia collected from the veins. Representative ore minerals in the deposit are electrum, argentite, aguilarite, polybasite, pearceite and lenaite. Dominant alteration minerals are adularia, α-cristobalite, chlorite, illite and kaolinite. Hydrothermal solutions of neutral pH were responsible for the mineralization, which is divided into six stages defined by tectonic boundaries. Gold mineralization occurred in stages I and III. Hydrothermal brecciation occurred during stages III, IV and VI. Stages II, IV, V and VI were barren. The estimated ore formation temperature based on a fluid inclusion study is 150 to 250 °C at a depth of approximately 170 m below the paleo-water table. Boiling of hydrothermal fluids is hypothesized as the cause of the intermittent deposition of gold ore. The sulfur and oxygen fugacities during the deposition of anhydrite prior to the hydrothermal brecciation were higher than those during the gold mineralization stages. The occurrence in the hydrothermal breccia of fragments of high grade Au-Ag and polymetallic ores suggests that higher grade mineralization of these metal ores might have occurred in a deeper portion of the deposit.read more
Citations
More filters
Journal ArticleDOI
Epithermal Gold-Silver Mineralization of the Asachinskoe Deposit in South Kamchatka, Russia
Abstract: The Asachinskoe epithermal Au-Ag deposit is a representative low-sulfidation type of deposit in Kamchatka, Russia. In the Asachinskoe deposit there are approximately 40 mineralized veins mainly hosted by dacite–andesite stock intrusions of Miocene–Pliocene age. The veins are emplaced in tensional cracks with a north orientation. Wall-rock alteration at the bonanza level (170–200 m a.s.l.) consists of the mineral assemblage of quartz, pyrite, albite, illite and trace amounts of smectite. Mineralized veins are well banded with quartz, adularia and minor illite. Mineralization stages in the main zone are divided into stages I–IV. Stage I is relatively barren quartz–adularia association formed at 4.7 ± 0.2 Ma (K-Ar age). Stage II consists of abundant illite, Cu-bearing cryptomelane and other manganese oxides and hydroxides, electrum, argentite, quartz, adularia and minor rhodochrosite and calcite. Stage III, the main stage of gold mineralization (4.5–4.4 ± 0.1–3.1 ± 0.1 Ma, K-Ar age), consists of a large amount of electrum, naumannite and Se-bearing polybasite with quartz–adularia association. Stage IV is characterized by hydrothermal breccia, where electrum, tetrahedrite and secondary covellite occur with quartz, adularia and illite. The concentration of Au+Ag in ores has a positive correlation with the content of K2O + Al2O3, which is controlled by the presence of adularia and minor illite, and both Hg and Au also have positive correlations with the light rare-earth elements. Fluid inclusion studies indicate a salinity of 1.0–2.6 wt% NaCl equivalent for the whole deposit, and ore-forming temperatures are estimated as approximately 160–190°C in stage III of the present 218 m a.s.l. and 170–180°C in stage IV of 200 m a.s.l. The depth of ore formation is estimated to be 90–400 m from the paleo-water table for stage IV of 200 m a.s.l., if a hydrostatic condition is assumed. An increase of salinity (>CNaCl≈ 0.2 wt%) and decrease of temperature (>T ≈ 30°C) within a 115-m vertical interval for the ascending hydrothermal solution is calculated, which is interpreted as due to steam loss during fluid boiling. Ranges of selenium and sulfur fugacities are estimated to be logfSe2 = −17 to −14.5 and logfS2 = −15 to −12 for the ore-forming solution that was responsible for Au-Ag-Se precipitation in stage III of 200 m a.s.l. Separation of Se from S-Se complex in the solution and its partition into selenides could be due to a relatively oxidizing condition. The precipitation of Au-Ag-Se was caused by boiling in stage III, and the precipitation of Au-Ag-Cu was caused by sudden decompression and boiling in stage IV.
Journal ArticleDOI
The Asachinskoe epithermal Au-Ag deposit in southern Kamchatka: physicochemical conditions of formation
TL;DR: The Asachinskoe epithermal Au-Ag deposit (southern Kamchatka) is referred to as low-sulfidation in quartz-adularia-sericite in Corbett's classification.
Journal ArticleDOI
Physicochemical formation conditions of silver sulfoselenides at the Rogovik deposit, Northeastern Russia
TL;DR: In this article, the chemical compositions of acanthite, naumannite, and associated ore minerals have been studied from the samples of polychronous Au-Ag ores at the Rogovik deposit.
Journal ArticleDOI
Ore-forming Ages and Sulfur Isotope Study of Hydrothermal Deposits in Kamchatka, Russia
Ryohei Takahashi,Hiroharu Matsueda,Victor M. Okrugin,Naotatsu Shikazono,Shuji Ono,Akira Imai,Elena D. Andreeva,Koichiro Watanabe +7 more
TL;DR: In this paper, the authors analyzed 13 ore deposits including hydrothermal gold-silver and base metal, in order to elucidate the geological time periods of ore formation, relationship to regional volcanic belts, type of mineralization, and origin of sulfur in sulfides.
Journal ArticleDOI
Polymetallic and Au‐Ag Mineralizations at the Mutnovskoe Deposit in South Kamchatka, Russia
TL;DR: The Mutnovskoe mine as mentioned in this paper is a polymetallic vein and Au-Ag quartz vein associated type of hydrothermal deposit located in the Porozhisto-Asachinskaya metallogenic province of South Kamchatka, Russia.
References
More filters
Book
Fluid-Mineral Equilibria in Hydrothermal Systems
TL;DR: In this article, the authors introduce the practical concepts and calculations involved in interpreting the chemistry of high-temperature fluids in geothermal systems and hydrothermal ore-forming environments.
Journal ArticleDOI
The effect of salinity on the maximum thermal gradient of a hydrothermal system at hydrostatic pressure
TL;DR: In this paper, the effect of salinity on the temperature-depth relations of a brine of constant composition, enclosed in a vein system, but freely connected to the surface, and everywhere at the boiling point for the hydrostatic head, was calculated by using a mathematical model.
Journal ArticleDOI
The chemistry of geothermal waters in Iceland. I. Calculation of aqueous speciation from 0° to 370°C
TL;DR: In this article, a computer program is developed to calculate the composition and aqueous speciation of geothermal reservoir waters including pH, redox potential and gas partial pressures, which is specifically suited to handle geochemical data from wet-steam wells, hot-water wells and boiling hot springs, but it may also be used for non-thermal waters.
Journal ArticleDOI
The chemistry of geothermal waters in Iceland. II. Mineral equilibria and independent variables controlling water compositions
TL;DR: The major element chemistry of Icelandic geothermal waters is predictable provided two parameters are known as mentioned in this paper, namely temperature and the mobility of chloride, which is known to have a significant effect on water chemistry.