Indosinian tectonics and mineral systems in China: an introduction

Abstract

Subduction-and collision-related orogenies usually accommodate hydrothermal mineralizations (Fig. 1;Chen et al., 2009;Pirajno, 2009). Hydrothermal mineral systems are more logically, briefly classified into three end-members according to the origins and P-T conditions of the causative hydrothermal fluids, i.e. epizonogenic, metamorphic, and magmatic. Epizonogenic hydrothermal deposits are formed by the fluids commonly generated at depths of <10 km and temperatures of <300°C, under a geothermal gradient of 30°C/km (Chen et al., 2007b(Chen et al., , 2009). This broad class can include the sedimentary-hosted (e.g. low-temperature hydrothermal Hg-Sb, Carlin-type Au, MVT Pb-Zn, and sandstone-type U or Cu), volcanic-hosted (or epithermal) Au-Ag ± Cu, and seafloor accumulated (SEDEX-type PbZn-Ag and VMS-type Cu-Zn-Au) hydrothermal mineral systems. Metamorphic hydrothermal deposits are formed by the fluids that originated from regionally metamorphic devolatilization at depths of >10 km and temperatures of >200°C (generally >300°C) and are present as structurally-controlled lodes. The regional metamorphism is usually associated with subduction-related or collisionrelated orogenies, and thus metamorphic hydrothermal deposits are also called orogenic-type and have been well documented (Chen et al., 2007b). In addition to the welldocumented orogenic Au lodes (Groves et al., 1998;Pirajno, 2009;Goldfarb et al., 2014) , 2011Ni et al., 2012), and Fe (Wan et al., 2012) deposits were recently reported and are worthy of further study. Magmatic hydrothermal deposits are formed mainly by the fluids exsolved from magmas that are commonly generated at depths of >20 km and temperatures of >600°C, with orebodies occurring inboard or outboard of the intrusive rocks (dykes, stocks, or batholiths), including porphyry-, skarn-, breccia pipe-, (carbonatite, syenite) dyke-, (quartz, fluorite) vein-, and greisen-types. Due to the discrepancy in (melt-)fluid-generating depths and temperatures, it is inferred that the epizonogenic fluids are characterized by low-salinity and CO 2 -poor, metamorphic fluids by low-salinity and CO 2 -rich, and magmatic fluids by high-salinity and variable content of CO 2 . The nature and differences of the fluids can be recorded by fluid inclusions, such as aqueous, carbonaceous, aqueous-carbonaceous, daughter mineral-bearing, and hydrocarbon inclusions, as well as melt inclusions. Obviously, case studies of hydrothermal deposits will test the inference.China is a unique area developed with three global tectonic-metallogenic domains, i.e. the Tethys, Palaeo-Asia, and Circum-Pacific, with the last overprinting the eastern parts of the former two domains ( Fig. 2; Chen et al

Geochemistry, zircon U–Pb analysis, and fluid inclusion 40Ar/39Ar geochronology of the Yingchengzi gold deposit, southern Heilongjiang Province, NE China

“…In recent decades, many studies have investigated the tectonic setting and evolution, sedimentology, magmatism, structural deformation, palaeobiogeography, and palaeomagnetism of the CAOB (Zhou and Wilde, , and references there in). According to these information and new evidence, most researchers consider that the complete closure of the Paleo‐Asian Ocean occurred in the late Permian–Early Triassic, and that the Solonker–Xra Moron River–Changchun suture represents the final suture zone between the North China and Siberia cratons (Xiao et al ., , ; Chen and Santosh, ; Li, ; Wu et al ., ; Chen et al ., 2009, 2014).…”

“…Thus, the Yingchegnzi mineralizing event was driven by the late Permian–Early Triassic continental collision regime between the North China and Siberia cratons, a tectonic event that generated ductile–brittle shear zones and faults within the Songnen–Zhangguangcai Range Massif which controlled the gold orebodies of Yingchengzi deposit. And this collision ultimately results in widely regional metamorphism, which was usually followed by intensive hydrothermal activities and triggered a large amount of mineralization of the CABO (Chen et al ., 2004, 2005, 2008, 2012, 2014a,b; D. F. Li et al ., 2014; Han et al ., ; J. Zhang et al ., 2014; Mao et al ., ; Wu et al ., ; Z.J. Zhang et al ., 2014; Zhang and Li, ).…”

Genesis of the Zhunsujihua porphyry Mo deposit in the Erenhot‐East Ujimqin metallogenic belt, Inner Mongolia, China: Evidence from geology, fluid inclusions, and isotope systematics

“…The Zhunsujihua deposit is characterized by low Mo grades (Wang et al, ), and the quartz veinlets from this deposit contain little or no CO 2 ‐bearing fluid inclusions (Figure ). Therefore, we suggest that the Zhunsujihua deposit belongs to the Endako‐type porphyry Mo deposit (Chen, Santosh, Somerville, & Chen, ;Chen, Zhang, Wang, et al, ; Chen, Wang, Li, Yang, & Pirajno, ; Wu, Zhou, Li, & Chen, ; Wu, Chen, & Zhou, ).…”

Fluid inclusion and isotope geochemistry of the Atebayue Sb deposit, South Tianshan Orogen, Kyrgyzstan

“…Atebayue is representative of the South Tianshan Sb deposits and is similar to many Hg─Sb deposits in the Qinling fold belt Chen, Santosh, Somerville, & Chen, 2014), such as the Gongguan and Qingtonggou Hg─Sb deposits (Zhang, Tang et al, 2014). The South Tianshan Hg─Sb belt, combined with the Qinling Hg─Sb belt, is the world's third largest Hg─Sb metallogenic province following the Circum-Pacific Rim and Mediterranean orogenic belts (Ding, 1986).…”