Early Cretaceous arc magmatism and high-sulphidation epithermal porphyry Cu–Au mineralization in Yanbian area, Northeast China: the Duhuangling example

Abstract

Yanbian area (Northeast China) is part of the Western Pacific porphyry-epithermal gold-copper metallogenic belt. Here, we present the results of a detailed study of Early Cretaceous mineralization-associated magmatic events in this region and, based on the results, identify the geological setting and mineralizing processes involved in mineral deposit formation. We focus on the timing and geodynamic mechanisms of hydrothermal alteration and metallogenesis of the Duhuangling highsulphidation epithermal gold deposit, located~15 km NW of the large Xiaoxinancha gold-rich porphyry copper deposit. New data are presented for zircon U-Pb, fluid inclusion Ar-Ar, whole-rock geochemical, and in situ zircon Hf isotopes for igneous rocks of the Duhuangling deposit, and the data -integrated with results of previous research -reveal that Yanbian area epithermal and porphyry Cu-Au deposits are associated with two stages of Early Cretaceous intermediate-felsic magmatism (116)(117)(118), with the later stage of magmatism more closely associated with mineral deposit formation. Our new data constrain the timing of formation of high-sulphidation epithermal gold deposits to 108-106 Ma and the timing of formation of gold-rich porphyry copper deposits to 111-109 Ma. The two stages of magmatism are associated with magmas derived from different sources, with the first-stage magmas potentially derived from partial melting of a depleted mantle wedge that had been metasomatized by subducted slab-derived fluids or melts; these first magmas are also mixed with material derived from the underplated lower crust. Second-stage magmas were probably generated by partial melting of subducting oceanic slab and some oceanic sediments and the interaction of these magmas with melts derived from the overlying lower crust. Most mineralization in the study area is associated with Cu-and Au-rich post-magmatic hydrothermal fluids that were generated during fractionation of hydrous, sulphur-rich, and high oxygen fugacity adakitelike/adakitic mixed magmas. The formation of both igneous rocks and mineral deposits in the study area occurred in a tectonic setting dominated by Late-Early Cretaceous subduction of the Izanagi or Pacific Plate beneath eastern Asia, indicating that the formation of epithermal and porphyry Cu-Au deposits in the Yanbian area involved subduction-derived fluids, melt modification, partial melting, magma mixing, and crystal fractionation.

Age of theYongxin Audeposit in theLesser Xing'an Range: Implications for anEarly Cretaceousgeodynamic setting for gold mineralization inNE China

“…The Sishanlinchang gold deposit has molybdenite Re–Os age of 111 ± 2 (Huang, Liu, & Gao, ), and the Sandaowanzi, Tuanjiegou, and Yongxin gold deposits have pyrite Rb–Sr isochron ages of ~119 to ~107 Ma (Wang et al, ; Zhai et al, ). The Duhuangling and Naozhi deposits have 40 Ar/ 39 Ar ages of 107 ± 6 and 124 ± 3 Ma, respectively, for fluid inclusions within auriferous quartz veins (Chai, Sun, Xing, Men, & Han, ; Men, ; Meng, Zhou, & Chai, ). The Shangmachang deposit has a Sm–Nd isochron age of 114 ± 4 Ma for hydrothermal calcite (Gao, ).…”

The 40Ar/39Ar dating of quartz: new insights into the metallogenic chronology of the Jinchang gold deposit and its geological significance

“…5). The Re-Os date of molybdenite from the Xiaoxi’nancha deposit is 111.1 ± 3.1 Ma 11 ; the Nongping deposit has a sericite 40 Ar/ 39 Ar date of 95.0 ± 3.1 Ma 13 ; a sulfide-bearing quartz vein from the Duhuangling deposit yielded a 40 Ar/ 39 Ar isochron age of 107 ± 6 Ma by laser probe techniques 14 ; in the Jiusangou deposit, metallogenic porphyritic quartz diorite yielded a zircon U-Pb age of 108.1 ± 1.4 Ma 31 ; Sun et al . 12 considered the Ciweigou and Wufeng-Wuxingshan deposits formed after 108 Ma based on the ages of mineralized intrusives and host volcanic rocks.…”

Geochronology of the giant Beiya gold-polymetallic deposit in Yunnan Province, Southwest China and its relationship with the petrogenesis of alkaline porphyry

“…Ballard et al (2002) measured the major and trace element compositions of zircons and whole rock samples from the porphyry Cu belt in northern Chile and deduced that porphyry Cu mineralization is directly associated with intrusions with zircon Ce (IV)/Ce (III) N 300 and Eu N / Eu N * N0.4; this signature provides a useful tool for evaluating the rock fertility for magmatic-hydrothermal Cu-Au mineralization. Given that the Ce (IV)/Ce (III) and Eu N /Eu N * ratios of zircon are good indicators of magmatic oxygen fugacity, most magmatic-hydrothermal Cu-Au deposits exhibit a strong relationship to intrusions with high oxygen fugacities (Blevin and Chappell, 1992;Candela, 1992;Sun et al, 2007;Liang et al, 2009;Chai et al, 2014). High oxygen fugacities change the valence state of sulfur in melts and suppress saturation of an immiscible sulfide phase that scavenges Cu (and Au) from a fractionating melt (Sun et al, 2004;Liang et al, 2006Liang et al, , 2010, which would favor the enrichment of chalcophile elements in magma during fractionation.…”