Two periods of mineralization in Xiaoxinancha Au–Cu deposit, NE China: evidences from the geology and geochronology

Abstract

The Xiaoxinancha Au–Cu deposit is located at the eastern segment of the Tianshan–Xingmeng orogenic belt in northeast China. The deposit includes porphyry Au–Cu orebodies, veined Au–Cu orebodies and veined Mo mineralizations. All of them occur within the diorite intrusion. The Late Permian diorite, Late Triassic granodiorite, Early Cretaceous granite and granite porphyry are developed in the ore area. The studies on geological features show that the porphyry Au–Cu mineralization is related to the Late Permian diorite intrusion. New geochronologic data for the Xiaoxinancha porphyry Au–Cu deposit yield Permian crystallization zircon U–Pb age of 257 ± 3 Ma for the diorite that hosts the Au–Cu mineralization. Six molybdenite samples from quartz + molybdenite veins imposed on the porphyry Au–Cu orebodies yield an isochron age of 110.3 ± 1.5 Ma. The ages of the molybdenites coeval to zircon ages of the granite within the errors suggest that the Mo mineralization was genetically related to the Early Cretaceous granite intrusion. The formation of the diorite and the related Au–Cu mineralization were caused by the partial melting of the subduction slab during the Late Palaeozoic palaeo‐Asia Ocean tectonic stage. The Re contents and Re–Os isotopic data indicate that the crustal resource is dominated for the Mo mineralization during the Cretaceous extensional setting caused by the roll‐back of the palaeo‐Pacific plate. Copyright © 2014 John Wiley & Sons, Ltd.

The Sources of Ore‐forming Fluids from the Jinchang Gold Deposit, Heilongjiang Province, NE China: Constraints from the He–Ar Isotopic Evidence

“…Besides, the Early Cretaceous Jinchang gold deposit is located in a continental margin arc setting (Zhao et al, ). The paleo‐Pacific plate tectonics in Early Cretaceous is in a transitional stage from compression–subduction to roll back and then to extension (Zeng et al, , , , ; Zhu et al, ). This change in the tectonic stress field results in extruded subduction fluids from the upper part of a subduction zone cause rocks partial melting to develop magma chamber at crust–mantle transitional zone, thus lead to a tectonic setting of regional extension.…”

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

“…These data lead us to argue that the epithermal gold deposits in the Lesser Xing'an Range and Zhangguangcai Range formed mainly between 124 and 107 Ma (Table 1; Figure 11). The mineralization ages of the epithermal gold deposits in the Zhangguangcai Range are also similar to the porphyry or porphyry-hydrothermal vein Cu-Au deposit at Xiaoxinancha and Nongping in the Zhangguangcai Range (Han, Sun, Bai, et al, 2013;Ouyang et al, 2013;Ren et al, 2015;Shu et al, 2016;Wang et al, 2010;Zeng, Guo, Zhou, & Duan, 2016) which Xiaoxinancha Cu-Au deposit has Molybdenite Re-Os age of (Ren, Wang, Qu, Zhao, & Chu, 2011 (Figure 12a). They proposed that the Cretaceous porphyry mineralization in NE China was related to slab rollback of Palaeo-Pacific Plate (Figure 12; Sillitoe, 2010;Chang et al, 2011;Shu et al, 2016).…”

“…These data lead us to argue that the epithermal gold deposits in the Lesser Xing'an Range and Zhangguangcai Range formed mainly between 124 and 107 Ma (Table ; Figure ). The mineralization ages of the epithermal gold deposits in the Zhangguangcai Range are also similar to the porphyry or porphyry‐hydrothermal vein Cu–Au deposit at Xiaoxinancha and Nongping in the Zhangguangcai Range (Han, Sun, Bai, et al, ; Han, Sun, Xing, et al, ; Ouyang et al, ; Ren et al, ; Shu et al, ; Wang et al, ; Zeng, Guo, Zhou, & Duan, ) which Xiaoxinancha Cu–Au deposit has Molybdenite Re–Os age of 111.1 ± 3.1 (Ren, Wang, Qu, Zhao, & Chu, ). Recently, Shu et al () argued that the Cretaceous porphyry Mo and Cu mineralization and associated magmatism define a southeastward‐younging trend,i.e., from 140 to 125 Ma in the Great Xing'an Range to 125–95 Ma in the Zhangguangcai Range and north‐eastern margin of North China Craton (Figure a).…”

Fluid Evolution, H-O Isotope and Re-Os Age of Molybdenite from the Baiyinhan Tungsten Deposit in the Eastern Central Asian Orogenic Belt, NE China, and Its Geological Significance

“…With the migration and evolution of the fluid, the proportion of meteoric water gradually increased. The Re content in molybdenite from the W-Mo-bearing quartz veins in the Baiyinhan tungsten deposit is consistent with many porphyry Mo deposits but is significantly smaller than those from porphyry Cu-Mo deposits [78]. The average Re contents of molybdenites from porphyry Cu-Mo deposits and porphyry Mo deposits range from 118-19,800 ug/g, and 4-68 ug/g, respectively [76].…”