Research output: Contribution to journal › Article › peer-review
Conditions of formation of Au-Se-Te mineralization in the Gaching ore occurrence (Maletoyvayam ore field), Kamchatka, Russia. / Tolstykh, Nadezhda; Vymazalova, Anna; Tuhy, Marek et al.
In: Mineralogical Magazine, Vol. 82, No. 3, 06.2018, p. 649-674.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Conditions of formation of Au-Se-Te mineralization in the Gaching ore occurrence (Maletoyvayam ore field), Kamchatka, Russia
AU - Tolstykh, Nadezhda
AU - Vymazalova, Anna
AU - Tuhy, Marek
AU - Shapovalova, Mariya
PY - 2018/6
Y1 - 2018/6
N2 - The Gaching high-sulfidation epithermal deposit in the Maletoyvayam ore field features a wide range of Se-containing minerals and selenides, as well as complex gold oxides, Au tellurides (calaverite, krennerite) and native gold typical for epithermal deposits. Pyrite included in quartzites and quartz-alunite rocks was probably formed during an early stage of the ore-forming process. During the following Au-rich stage, the / increased with being relatively high, resulting in the formation of very rare compounds that have not been previously described in nature. These include Au2Te4(Se,S)3, Se3Te2, AuSe and Au(Te,Se,S) phases. The Au2Te4(Se,S)3 compounds have some variations in composition: the complete isomorphic series between Au2Te4Se3 and Au2Te4S3 was observed. The gold and Au-minerals at the main ore stage can be stable within a range of log of -27.3 and atmospheric oxygen (?); log between -12.4 and -5.7; log between -10.5 and -7.8; and log between -12.8 and -6.8 (at 250°C). The increasing oxygen fugacity during the final stage of mineralization resulted in the formation of complex Sb,As,Te,S-bearing Au oxides. Gold-oxide formation occurs due to oxidation of Au-tellurides. The final products of this process are newly-formed secondary mustard gold and Te-Se solid solutions.
AB - The Gaching high-sulfidation epithermal deposit in the Maletoyvayam ore field features a wide range of Se-containing minerals and selenides, as well as complex gold oxides, Au tellurides (calaverite, krennerite) and native gold typical for epithermal deposits. Pyrite included in quartzites and quartz-alunite rocks was probably formed during an early stage of the ore-forming process. During the following Au-rich stage, the / increased with being relatively high, resulting in the formation of very rare compounds that have not been previously described in nature. These include Au2Te4(Se,S)3, Se3Te2, AuSe and Au(Te,Se,S) phases. The Au2Te4(Se,S)3 compounds have some variations in composition: the complete isomorphic series between Au2Te4Se3 and Au2Te4S3 was observed. The gold and Au-minerals at the main ore stage can be stable within a range of log of -27.3 and atmospheric oxygen (?); log between -12.4 and -5.7; log between -10.5 and -7.8; and log between -12.8 and -6.8 (at 250°C). The increasing oxygen fugacity during the final stage of mineralization resulted in the formation of complex Sb,As,Te,S-bearing Au oxides. Gold-oxide formation occurs due to oxidation of Au-tellurides. The final products of this process are newly-formed secondary mustard gold and Te-Se solid solutions.
KW - epithermal gold deposit
KW - Gaching ore occurrence
KW - AuSe
KW - Au(Te,Se,S)
KW - Au2Te4(Se,S)(3 )unnamed phases
KW - Au oxide
KW - oxygen fugacity
KW - tellurium fugacity
KW - selenium fugacity
KW - sulfur fugacity
KW - EPITHERMAL GOLD
KW - PHASE-RELATIONS
KW - DEPOSITS
KW - OXIDES
KW - TELLURIDES
KW - MINERALOGY
KW - SELENIDES
KW - SULFIDES
KW - GENESIS
KW - Au Te (Se,S) unnamed phases
UR - http://www.scopus.com/inward/record.url?scp=85056236516&partnerID=8YFLogxK
U2 - 10.1180/mgm.2018.84
DO - 10.1180/mgm.2018.84
M3 - Article
VL - 82
SP - 649
EP - 674
JO - Mineralogical Magazine
JF - Mineralogical Magazine
SN - 0026-461X
IS - 3
ER -
ID: 18647176