TELLURIDE AND Bi-SULFOSALT MINERALOGY OF THE YANGZHAIYU GOLD DEPOSIT, XIAOQINLING REGION, CENTRAL CHINA

Abstract

The Xiaoqinling vein-style gold district (reserves of >630 t Au) has a very pronounced tellurium signature. The Yangzhaiyu gold deposit is one of the largest gold deposits in this district. The ore-mineral assemblage consists of pyrite, chalcopyrite, galena, bornite, sphalerite, gold, and native tellurium together with a wide variety of telluride and Bi-sulfosalt minerals. The telluride mineral assemblage comprises Phase A, sylvanite [(Au,Ag) 2 Te 4 ], hessite [Ag 2 Te], petzite [Ag 3 AuTe 2 ], calaverite [AuTe 2 ], stützite [Ag 5−x Te 3 ], rucklidgeite [PbBi 2 Te 4 ], altaite [PbTe], volynskite [AgBiTe 2 ], tellurobismuthite [Bi 2 Te 3 ], tetradymite [Bi 2 Te 2 S], and buckhornite [AuPb 2 BiTe 2 S 3 ]. The Bi-sulfosalt minerals observed are Phase B, aikinite [PbCuBiS 3 ], felbertalite [Cu 2 Pb 6 Bi 8 S 19 ], and wittichenite [Cu 3 BiS 3 ]. We observed two unnamed phases: Phase A and Phase B. Phase A, with the empirical formula of AgTe 3 , occurs in small intergrowth aggregates with sylvanite and chalcopyrite, and locally with bornite, galena, and altaite. Phase A and its associated minerals occur along healed micro-fractures in pyrite. It has a distinctly golden reflection color, without discernable reflectance pleochroism or anisotropy. AgTe 3 was synthesized in 1982, but its natural occurrence has not been reported to date. Phase B, with the empirical formula of Cu 20 FePb 11 Bi 9 S 37 , was observed in an intergrowth aggregate together with hessite, galena, chalcopyrite, bornite, and buckhornite. It has a pinkish grey reflection color, without discernable reflectance pleochroism or anisotropy. The telluride and gold mineralization took place at or below ca. 220°C and evolved towards decreasing f Te2 . The ore-forming fluids and components of the Yangzhaiyu gold deposit may ultimately stem from refertilized upper mantle, either directly from devolatilization or from a magmatic system resulting from partial melting.

Geology, Mineralogy, Geochronology, and Sulfur Isotope Constraints on the Genesis of the Luanling Gold Telluride Deposit, Western Henan Province, Central China

“…Petzite contains 43.14–43.46 wt% Ag, 21.23–21.56 wt% Au, and 34.92–35.34 wt% Te. Some petzite analyses gave much lower Au contents than ideal petzite (25.4 wt%), which was most likely the result of Au diffusion away from the electron beam during EPMA measurement (Rucklidge & Stumpfl, ; Jian et al, ).…”

Geochronology and fluid source constraints of the Songligou gold‐telluride deposit, western Henan Province, China: Analysis of genetic implications

“…Except the enrichment of Te in the Songligou gold‐telluride deposit, Te‐rich hydrothermal fluid played an important role in the Xiaoqinling‐Xiong'ershan district from Late Triassic to Early Cretaceous, which indicated that there could be an enriched source of Te in this district. Tellurides were not only found in Late Cretaceous gold deposit, for example, Qiyugou (Shao & Luan, ; Wang et al, ; Han et al, ), Yangzhaiyu (Li et al, ; Jian et al, ), Wenyu (Li et al, ; Zhao et al, ), and Fancha (Li et al, ; Ren, ) gold deposit. Besides, tellurides were also found in the Early Cretaceous Jinduicheng porphyry Mo deposit (Stein, Markey, Morgan, Du, & Sun, ; Sun et al, ).…”

“…Except the enrichment of Te in the Songligou goldtelluride deposit, Te-rich hydrothermal fluid played an important role in the Xiaoqinling-Xiong'ershan district from Late Triassic to Early Cretaceous, which indicated that there could be an enriched source of Te in this district. Tellurides were not only found in Late Cretaceous gold deposit, for example, Qiyugou (Shao & Luan, 1989;Wang et al, 2001;Han et al, 2007), Yangzhaiyu (Li et al, 2012c;Jian et al, 2014), Wenyu Zhao et al, 2012), and Fancha Ren, 2012) gold F I G U R E 1 7 Gold-bearing quartzpyrite veins cutting across granite porphyry intrusions in the Shangzhuang (a) and Gongyu (b) gold deposits. Abbreviations: Py = Pyrite; Qtz = Quartz deposit.…”

“…The Xiaoqinling‐Xiong'ershan district in the southern margin of the North China Craton (NCC) is the second largest gold concentration area in China, where abundant telluride species have been found in some gold deposits (Jian et al, , ; Li et al, ; Ren, ; Shao & Luan, ; Zhao, Jiang, & Frimmel, ; Zhao, Ren, Li, & Ding, ). Ages of gold‐telluride mineralization in this region have been identified as being of the Late Triassic (Jian et al, ; Tang, ), Late Jurassic (Chao et al, ; Li et al, ), and Early Cretaceous (Li et al, 2012b,c).…”

Mineral Paragenesis and Ore‐Forming Processes of the Dongping Gold Deposit, Hebei Province, China

“…Tellurides of Au, Ag, Pb, and other metals are common trace minerals in gold deposits. The mineralogy, paragenesis, and physicochemical conditions of ore‐forming fluids in telluride‐bearing deposits have been studied intensively (Spry & Thieben, ; Pals & Spry, ; Sung et al, ; Jian et al, ; Xu et al, ; Zhai & Liu, ; Liu et al, ). Telluride melts can scavenge gold from Au‐bearing minerals through coupled dissolution–reprecipitation reactions in hydrothermal fluids even under low temperature conditions (Frost et al, ; Ciobanu et al, ; Cook et al, , b), and these reactions can result in overprinting characters in many gold telluride deposits (Ciobanu et al, ; Cook et al, ; Bi et al, ).…”