Gold mineralization of the Khaak-Sair gold–quartz ore occurrence in listwänites (western Tuva)

Abstract

We consider mineral assemblages and mineralogical and geochemical peculiarities of hypogene gold from the Khaak-Sair multistage low-sulfide gold-quartz ore occurrence in listwänites. Three productive substages of Au-and Ag-mineral formation have been recognized on the basis of mineralogical studies: gold–sulfosalt–sulfide–quartz, gold–mercury–quartz, and gold–selenide–telluride–sulfide–quartz. These substages were characterized by the following sequences of mineral formation: (1) ultrahigh-fineness gold → high-fineness gold → argental gold (medium- and low-fineness gold) → electrum + Ag-bearing and argental fahlores (up to 50 wt.% Ag) ± acanthite ± hessite; (2) high-fineness gold → Hg-bearing and mercurian gold → mercurian electrum → mercurian kustelite → Au-bearing mercurian silver; and (3) high-fineness gold → mercurian gold → mercurian electrum + naumannite + Te-bearing naumannite + fischesserite + tiemannite + hessite + coloradoite + Ag-bearing minerals of the galena–clausthalite series (up to 6 wt.% Ag) ± Se-cinnabar ± Se-imiterite. Productive mineral assemblages of the ore occurrence formed in the hypabyssal facies (depth ~ 1.5 km, P ~ 0.5 kbar) on the background of a temperature decrease from 290 to 160 °C and variations in f(O2), f(S2), f(Se2), and f(Te2).

Mapping Listvenite Occurrences in the Damage Zones of Northern Victoria Land, Antarctica Using ASTER Satellite Remote Sensing Data

“…Terrane boundaries are major tectonic discontinuities that often display a complex and polyphase structural evolution, and a variety of ore mineralizations were reported in these boundaries [2,3]. Listvenite, a carbonate-silica-dominated rock that forms as a result of CO 2 -and K-metasomatism of ultramafic/mafic rocks, represents a key indicator for the occurrence of ore mineralizations along shear zones or major tectonic boundaries [20][21][22][23][138][139][140]. The ability to map hydrothermal alteration mineral and listvenites using spectral bands of ASTER satellite remote sensing data has been successfully established in many parts of the world [6][7][8][9][10][11][12][27][28][29]31,43].…”

“…It is formed by interaction of mafic and ultramafic rocks with low to intermediate temperature CO 2 -and S-rich fluids, and is commonly found along the major fault and shear zones at terrane boundaries or major tectonic units in orogenic systems [13][14][15][16]. As such, listvenite is spatially associated with ophiolites, greenstone belts and suture zones in orogenic belts [17][18][19][20][21][22][23][24]. Listvenite occurrences are considered to represent key indicators for certain mineral associations connected with ore mineralizations such as gold and other hydrothermal deposits like Ag, Hg, Sb, As, Cu, Ni, Co, as well as magnesite and talc [14,18,20,25,26].…”

The Ulug-Sair Gold Occurrence (Western Tuva, Russia): Mineralogy, Ore Genesis, and S-O Isotope Systematics

“…In addition, numerous gold mineralizations are associated with medium-temperature quartz-carbonate-sericite-and quartz-carbonate-fuchitealtered rocks. The largest are Khaak-Sair, in quartz-carbonate-fuchsite rocks [30], and Ulug-Sai, in conglomerates, siltstones, and quartz-carbonate-sericite rocks. They are located in the AMOC, which is considered one of the most promising for native Au (Figure 1) in the region.…”

“…Gold mineralization is related to the intrusions and dikes of the Late Devonian Bayankol complex, comprising granodiorites and tonalite, rhyolite, and granodiorite porphyries [29,30]. The 40 Ar/ 39 Ar age of ore-bearing quartz-carbonate-fuchsite-altered rocks (379.4 ± 4.4 Ma) of the Khaak-Sair occurrence is 376.5 ± 3.4 Ma for phase III gabbro dikes of the Bayankol complex, thereby confirming the genetic relationship of mineralization with the Late Devonian Bayankol intrusive complex [32].…”

The Ulug-Sair Gold-Bismuth Ore Occurrence (Western Tuva, Russia): PT Parameters, The Composition of Fluids, and Isotopy of S and O

“…and numerous gold mineralization points associated with medium-temperature beresite and listvenite metasomatites. The largest of them are the occurrences of the Khaak-Sair in listvenites [1] and the Ulug-Sair -in conglomerates, siltstones, and beresites. They are located in the Aldan-Maadyr ore cluster (AMOC), which is considered one of the promising ore clusters for native Au (Figure 1) in the region.…”