U–Pb dating of hydrothermal zircon from the Dongping gold deposit in North China: Constraints on the mineralization processes

Metallogeny of the syenite-related Dongping gold deposit in the northern part of the North China Craton: A review and synthesis

“…It was thus proposed that the metals were derived from leaching of the Shuiquangou syenites by the circulating hydrothermal fluids related to the development of Late JurassicEarly Cretaceous granitic intrusions (Bao and Zhao, 2006;Mo et al, 1997;Song and Zhao, 1996). However, the Ar-Ar ages for the hydrothermal gold mineralization cannot be correlated with any specific tectonomagmatic event in the study area and these data are inconsistent with the more reliable U-Pb ages obtained on hydrothermal zircons from the ores (Bao et al, 2014). A model linking gold mineralization to alkalic magmatism has been proposed by some geologists based on the ore-metal association (they are similar to those of epithermal Au deposits associated with alkaline magmatic rocks), and based on the close spatial relationship of the gold mineralization with the syenite intrusion.…”

“…As discussed above, the hydrothermal zircons from the highgrade auriferous quartz veins and disseminated ores have been dated at~385 Ma, which is immediately after the emplacement of the Shuiquangou syenite intrusion (Bao et al, 2014). The hydrothermal zircon grains from the low grade auriferous quartz vein, which crosscut the early stage high-grade ore veins, have been dated at~140 Ma, indicating the Late Jurassic-Early Cretaceous hydrothermal overprint (Bao et al, 2014;Li et al, 2010Li et al, , 2012b. Note: The samples were analyzed at the State Key Laboratory of Isotope Geochemistry using VG-354 and the details were described in Bao et al (2000).…”

“…Ar ages of the K-feldspar, sericite, quartz vein and U-Pb ages of the hydrothermal zircon from the ores, and the regional magmatism. Ages of the magmatic rocks including the Shuiquangou syenite, Honghualiang, the Guzuizi, Shangshuiquan, and Beizhazhi granites, and the Zhuanzhilian diorite (Bao et al, 2014;Jiang et al, 2007;Li and Bao, 2012;Miao et al, 2002). U-Pb ages of the hydrothermal zircons for the Dongping and Hougou gold deposits are from Bao et al (2014) and Li et al (2012b).…”

“…Single zircon U-Pb results ranging from 410.5 ± 1.4 Ma to 1667 ± 11 Ma are also questionable because of the lack of structural studies Liang et al, 1998). The more recent LA-ICPMS and SHRIMP zircon U-Pb dating show that the Shuiquangou syenite intrusion may have experienced a prolonged history of crystallization, i.e., zircons from the hornblende syenite in the western part, K-feldspar syenite in the middle part, and quartz syenite in the eastern part of the intrusion were dated at 400 ± 3.5 Ma, 390 ± 6 Ma, and 386 ± 6 Ma, respectively (Bao et al, 2014;Miao et al, 2002). Bao et al (1996), , and Zhao et al (2010).…”

“…The hydrothermal zircons were dated at~385 Ma by LA-ICPMS and SIMS U-Pb, indicating that they formed during the main stage of gold mineralization in the Devonian (Bao et al, 2014). The hydrothermal zircons from the low-grade auriferous quartz vein of the Dongping gold deposit have been dated at 147.8 ± 2.3 Ma (SIMS) and 140.3 ± 1.4 Ma (LA-ICPMS) (Bao et al, 2014;Li et al, 2010); these ages are attributed to a Late Jurassic-Early Cretaceous hydrothermal overprint caused by the intrusion of the Shangshuiquan granite and the Zhuanzhilian diorite (Bao et al, 2014). On this basis, we suggest that the Dongping gold deposit was mainly formed in the Devonian and overprinted by Late Jurassic-Early Cretaceous hydrothermal activity (Fig.…”