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The Baishitouwa deposit is a medium-scale quartz–wolframite vein-type deposit in the southern Great Xing'an Range tungsten (W) belt. The W mineralization occurs mainly as veins and dissemination within the mica schist of the Mesoproterozoic Baiyunebo Group. The formation of the deposit can be divided into four stages. The wolframite yielded a lower intercept 206Pb/238U age of 221.0 ± 3.4 Ma (1σ, MSWD = 2.0), which records a late Triassic W mineralization event in the Baishitouwa deposit. In combination with previous geochronological data, we suggest that NE China may have an enormous potential for Triassic W mineralization and more attention should be given to the Triassic ore prospecting in the region. This work highlights that the chemical composition of wolframite is controlled by both the crystallochemical parameters and the composition of the primary ore-forming fluid. Trace-element compositions suggest that wolframite (I) was controlled by the substitution mechanism of 4A(Fe, Mn)2+ + 8BW6+ + B□ ↔ 3AM3+ + AN4+ + 7B(Nb, Ta)5+ + 2BN4+, whereas wolframite (II) was controlled by the substitution mechanism of A(Fe, Mn)2+ + A□ + 2BW6+ ↔ 2AM3+ + 2BN4+. Wolframite (I) contains higher concentrations of Nb, Ta, Sc, and heavy rare earth elements (HREEs), and lower Mn/(Mn + Fe) ratios than wolframite (II). Both wolframite (I) and (II) have similar trace elements and left-dipped REEN patterns, and analogical Nb/Ta ratios. They have similar Y/Ho ratios to Mesozoic highly fractionated W-mineralized granitoids in NE China. These data indicate that the W mineralization at Baishitouwa is genetically related to an underlying highly fractionated granite, and the compositional variation of fluids is likely driven by crystallization of wolframite during the processes of fluid evolution. A change of the ore-forming fluids from an oxidized to a relatively reduced state during the evolution occurred from stage 1 to 2. [ABSTRACT FROM AUTHOR]

• Mineralization and magmatism occurred simultaneously in the Middle Triassic. • Four stages of mineralization are identified, which have different genesis. • Gold shows a genetic relationship with As, and an inverse correlation with Co and Ni. • The Yanjingou gold deposit is a shallow denudation orebody. • The Yanjingou gold deposit is an intrusion-related orogenic gold deposit. [Display omitted] The Wulonggou gold district is one of the most important gold producers of the East Kunlun metallogenic belt in China. Due to its complex geological background and limited investigations, the age of mineralization and ore-forming process remain unclear. Here, we focus on the Yanjingou gold deposit which is the largest and most typical deposit in the Wulonggou gold district, with a view to investigate the metallogenic mechanism and timing of ore formation with a view to evaluate the ore-forming processes and sources through a comprehensive study of the ore mineralogy, monazite and zircon U-Pb dating, in situ trace element analysis and mapping, and in situ S isotopes. Our results show that the magmatism and mineralization were coeval, during 239 Ma and 244 Ma in the Middle Triassic. Four stages of mineralization are identified with distinct textures, mineral assemblages, trace element characteristics and S isotopes. Stage 1 is represented by euhedral pyrite bearing quartz veins, which originated from deep metamorphic fluid, and was rarely affected by magmatic hydrothermal fluids. Stage 2 is characterized by the occurrence of abundant oriented arsenopyrite, which originated from the mixture of deep metamorphic fluid and magmatic hydrothermal fluid. Stage 3 is characterized by the occurrence of polymetallic sulfide of copper, with two generation of pyrite (stage 3 Py1 and Py2). Stage 3 Py1 formed from magmatic hydrothermal fluids whereas Py2 originated from deep metamorphic fluid and was also slightly influenced by magmatic hydrothermal fluids. Stage 4 is represented by late calcite and pyrite combination, which originated from another stage of deep metamorphic fluid. Stage2 and 3 are the main gold mineralization stages, and Au has a close relationship with As, and an obvious inverse correlation with Co and Ni. Combined with the trace element characteristics, we infer that the denudation degree of the Yanjingou gold deposit is very shallow with good prospects for exploration. Through multi-proxy investigation of the different stages and types of pyrite, we postulate that the Yanjingou gold deposit is an orogenic gold deposit related to intrusive rocks formed during Middle Triassic compressional transformation. [ABSTRACT FROM AUTHOR]

The Wulonggou Au district in the East Kunlun Orogen is one of the most important Au producing regions in China. The Yanjingou Au deposit occurs within a shear zone in the northeastern Wulonggou Au district. Based on detailed field investigations, geochemical data for the primary halo, and in situ thermoelectric data for pyrite, the following key results were obtained: (1) the Yanjingou Au deposit has the fractured-altered-rock type gold mineralization that is arsenopyrite-rich; (2) elemental correlations and cluster analysis show that Au and As are the most diagnostic elements; (3) geochemical data for the primary halo indicate the deposit is a shallow supra-ore halo ore body; and (4) in situ pyrite thermoelectric data show that the proportion of P-type pyrite is >80% and the detachment rate is 50%, which can be inferred that the location of the ore body is shallow. Based on our data, we present a mineralization prediction model for the ore body. The Yanjingou Au deposit has a good mineralization and high prospecting potential, with at least half of the ore body being concealed at depth, which has important scientific guiding significance for the breakthrough of prospecting and exploration. [ABSTRACT FROM AUTHOR]

The destruction of the North China Craton (NCC) culminated during the Early Cretaceous, inducing widespread magmatism and related mineralization in the eastern China. The Shizhuzi magmatic complex (SMC) from the Liaodong Peninsula is typical products of this event, thus could provide important insights on the destruction process. Here, we present petrological, geochronological, and elemental and isotopic geochemical data for the SMC rocks in order to reveal their magma sources, petrogenesis and the possible geodynamic process. The complex comprises quartz diorite, granodiorite, and granite, accompanied with Au, Cu and Mo mineral deposits. Zircon U Pb dating shows that the different rocks were coeval with the formation ages of 129–126 Ma, coincident with the associated mineralization. However, field relations, whole-rock major and trace element contents and isotopic compositions indicate different origin for the quartz diorites and the coeval granodiorites and granites. The quartz diorites are calc-alkaline rocks with high MgO, Mg# and low SiO 2. They are enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depleted in high field strength elements (HFSEs) with significant negative Nb, Ta and Ti anomalies. These geochemical data and the highly enriched zircon Hf isotopes suggest that they were derived from partial melting of enriched subcontinental lithospheric mantle. The granodiorites and granites from the SMC have high SiO 2 and low MgO contents, suggesting that they were derived from crustal sources. These rocks are I-type rocks with high-K calc-alkaline features. Their primary magma originated from the partial melting of basaltic lower crust and experienced fractional crystallization. The ascending mantle-derived magma provided heat for the melting of the crustal rocks. Based on regional geology, the SMC was generated in the extensional setting related to the roll-back of the subducted Paleo-Pacific plate. The concurrent mantle and crustal melting in the formation of the SMC revealed the loss of stability of the cratonic lithosphere, related to the destruction of the NCC during Early Cretaceous. Besides, the emplacement of SMC might also contribute to the formation of contemporaneous Au, Mo, and Cu deposits. • The SMC was formed in the Early Cretaceous and contributed to Mo–Au–Cu mineralization. • The melting of the mantle and crust occurs simultaneously during the SMC formation. • Two stage evolution: quartz diorite (mantle influenced) to granodiorite and granite. • Hornblende, plagioclase and zircon play an important role in the fractionation. • The SMC was formed in an extensional setting related to the destruction of NCC. [ABSTRACT FROM AUTHOR]

The Xiling gold deposit (>592 t @ 4.02 g/t) in the eastern Zhaoyuan-Laizhou gold belt of the Jiaodong Peninsula, is currently the largest gold deposit and deepest gold mine in China. This study presents microthermometric fluid inclusions data on quartz gangue, as well as trace element and S isotope data on pyrite from different mineralization stages and depths in the Xiling gold deposit to provide new insights into the spatio-temporal evolution of the ore-forming fluid that led to a giant Early Cretaceous gold deposit in the Jiaodong Peninsula. The δ34S values of pyrite range from 7.5 to 15.2 ‰, but vary temporally and spatially, reflecting a changes in physicochemical conditions as the ore-forming fluid migrated to different crustal levels over time, also suggesting Precambrian basement as the principal sulfur source. Trace element analyses of pyrite revealed that ore-forming metals were scavenged from the wall rock and then incorporated into the pyrite. Fluid inclusions data reveal that the ore-forming H 2 O-CO 2 -NaCl ± CH 4 fluid had a medium to high temperature (283–401 °C), medium-low salinity (1.91–8.00 wt% NaCl equivalent), analogous to most gold deposits in the Jiaodong Peninsula. Intensive interaction between the ore-forming fluid and wall rock changed the physicochemical conditions of fluid, leading to gold precipitation. The study supports the notion of the ore fluid of Jiaodong-type gold deposit having originated from a metasomatized lithospheric mantle. • Spatio-temporal fluid evolution is recorded by sulfur isotopes and trace element contents of pyrite. • The ore-forming fluids formed in a H 2 O-CO 2 -NaCl ± CH 4 hydrothermal system • The intensive fluid-rock interaction is the key for Xiling gold mineralization. • The Xiling deposit can be classified as the Jiaodong-type gold deposits. [ABSTRACT FROM AUTHOR]