Geological characteristics, deposit type, and metallogenic epoch of the Katebasu gold–copper deposit in western Tianshan

Abstract

The Katebasu gold (Au)–copper (Cu) deposit is one of the extra large‐scale Au–Cu deposits discovered in the western Tianshan Mountains in Xinjiang in the recent years. The geological characteristics of the deposit have not been systematically studied and summarized, and there is considerable debate about the deposit type and metallogenic epoch. In this paper, we studied the Katebasu Au–Cu deposit orebody production characteristics, ore mineral composition, structural tectonic, surrounding rock alteration, and metallogenic phases. We identified the deposit types, presented a new discussion on the metallogenic epoch combined with the study of garnet Sm–Nd chronology, and indicate that the deposit type is a skarn type–fracture zone alteration rock type. The skarn‐type Cu–Au deposit is mainly distributed in the fault fracture zone and skarn in the contact zone between the rock mass and marble strata. The fracture zone alteration‐type Au–Cu deposit is mainly distributed in the monzonite granite fracture zone. The mining area has two phases of metallogenesis, which are related to monzonite granite and diorite dykes, respectively, and have a certain degree of superposition in space. The early metallogenesis occurred at 334.3 ± 6.7 Ma. The above results provide direction for regional prospecting.

Tectonic Transformation and Metallogenesis of the Yanshan Movement during the Late Jurassic Period: Evidence from Geochemistry and Zircon U-Pb Geochronology of the Adamellites in Xingcheng, Western Liaoning, China

“…Driven by magmatic thermodynamic forces, the metallogenic material in ancient geological bodies activated, migrated, concentrated, and finally located in granitic gneisses, and then formed the hydrothermal deposit [85]. We investigated the geochronological ages from Mesozoic deposits and magmatic rocks exposed in western Liaoning to determine the association between the Yanshan Movement and mineralization [17,28,44,46,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89]. Table 3 summarizes the results of the numerical age data of magmatic rocks and deposits from the western Liaoning.…”

“…Frequency diagrams of compiled geochronological ages from Mesozoic deposits and magmatic rocks exposed in western Liaoning. Data sources are as follows [17,28,44,46,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89].…”

Tianshan Orogen along the Silk Road (Volume 3): Orogen links, geochemistry, geochronology, mineral deposits, and environments

“…1.94 Ga and underwent metamorphism immediately afterwards, related to a collisional orogeny, forming a part of the Columbia supercontinent. Liu and Han ( ) describes the Katebasu gold–copper deposit of western Tianshan which they regard as a skarn‐type fracture zone alteration in monzonite granite and diorite dykes. Sm–Nd dating of garnets in the skarn infer a Carboniferous age for the early metallogenesis.…”

Hydrothermal monazite trumps rutile: Applying U-Pb geochronology to evaluate complex mineralization ages of the Katbasu Au-Cu deposit, Western Tianshan, Northwest China

“…Recent researchers have elaborated on the chronology and genesis of ore-hosting granites, ore deposit geology, structural characteristics, gold mineralization ages, fluid inclusions, and H-O-S-Pb isotopes of the Katbasu gold-copper deposit (Feng et al 2014;Gao et al 2015;Zhang et al 2015;Dong et al 2018;Liu et al 2018;Zhao et al 2019). The diachronous ages of pyrite in the Katbasu deposit (310.9 ± 4.2 Ma from pyrite Re-Os, Zhang et al 2015;322.5 ± 6.8 Ma from pyrite Rb-Sr, Dong et al 2018) indicate that the gold mineralization occurred much later than the ore-hosting granite (zircon U-Pb ages of 359.8 -345.5 Ma, Feng et al 2014;Dong et al 2018;).…”

“…These ages are considerably older than the auriferous pyrite Rb-Sr and Re-Os isochron ages of 322.5 ± 6.8 Ma(Dong et al 2018) and 310.9 ± 4.2 Ma(Zhang et al 2015), indicating an early Cu-Au event before the major Au mineralization event in the Katbasu deposit. In addition, the ages of the 6.7 Ma;Liu et al 2018) in skarn and an40 Ar/ 39 Ar plateau age for sericite (268.6 ± 1.8 multi-stage tectonic events (Zhao et al 2019), we consider that the40 Ar/ 39 Ar plateau age of sericite may record a post-ore tectonic thermal event in the Katbasu deposit.6.2 Genetic type of the Katbasu Au-Cu depositThe Chinese western Tianshan orogenic belt hosts many large epithermal gold deposits(Jinxi-Yelmand, Long et al 2005; Axi, An and Zhu 2018) as well as orogenic gold deposits (Sawayaerdun,Chen et al 2012; Wangfeng, Zhang et al 2012).As a newly discovered large Au-Cu deposit in the western Tianshan, the genetic type of the Katbasu deposit remains controversial, with some researchers relating them to orogenic gold deposits(Zhang et al 2015;…”