Contributions of juvenile lower crust and mantle components to porphyry Cu deposits in an intracontinental setting: evidence from late Mesozoic porphyry Cu deposits in the South Qinling Orogenic Belt, Central China

Geochemistry, zircon U–Pb geochronology and Lu–Hf isotopes of the Late Jurassic granitoids from the Shuangyuangou deposit, South Qinling, China: Implications for petrogenesis and porphyry Cu metallogeny

“…Xiong et al, 2019;Zhang et al, 2021). After the Triassic continental-continental collision and crustal thickening between the NCB and SCB, the QOB entered an intracontinental evolution stage (Chen et al, 2023;. Xiong et al, 2019;Zhang et al, 2021).…”

“…However, continental collision zones and intra‐continental settings are also important settings for porphyry mineralization (Hou et al, 2020; Hou & Yang, 2009; Richards, 2009; Wang, Liu, et al, 2021; Wang, Luo, et al, 2021; Yang, Lu, et al, 2015), such as large PCDs produced in non‐arc settings in Gangdese belt and East Qinling metallogenic belt (Hou et al, 2020; Tang et al, 2021; Tang, Wagner, et al, 2022). The PCDs in island arc setting are generally formed by magmas originated from partial melting of the mantle wedge that was metasomatized by dehydration of the subducted oceanic crust (Cooke et al, 2005; Richards, 2003; Sillitoe, 2010), whereas those in the non‐arc settings are mainly related to the remelting of the juvenile lower crust caused by the upwelling of the mantle magma (Chen et al, 2023; Hou et al, 2013, 2020; Xiong et al, 2019). These porphyry deposits are usually related to hydrous, oxidized, and intermediate to felsic magmas which are derived from partial melting of lithospheric mantle or lower crust, evolved through magma ascending into the middle to upper crust, with fluid exsolved into the apical part of small apophysis (Park et al, 2021; Richards, 2022, 2009; Sillitoe, 2010).…”

“…The Qinling orogenic belt (QOB) is a composite orogenic belt formed by Palaeozoic to Mesozoic convergence between the North China Craton and the Yangtze Craton (Figure 1; Dong & Santosh, 2016; Dong et al, 2021; Meng & Zhang, 2000), with widely Late Jurassic to Early Cretaceous granitic intrusions ranging in age from 160 to 130 Ma (Cao et al, 2015; Wang et al, 2013). These intrusions are considered as the products of intra‐continental extension after the collision between the North China and South China cratons (Chen et al, 2023; Dong et al, 2021; Dong & Santosh, 2016), westward subduction of the paleo–Pacific Plate (Hong et al, 2018; Mao et al, 2011). However, in contrast to the typical porphyry systems in magmatic arcs, Late Mesozoic granitic magmatism and porphyry mineralization in QOB are not directly related to dehydration and partial melting by plate subduction.…”

“…The porphyry systems in the Shan–Zha area of the South Qinling are related to small stocks of diorite, granodiorite, quartz diorite porphyry, granite porphyry and granodiorite porphyry in the Chigou, Lengshuigou, Xiaohekou, Tudigou, Shuangyuangou and Xiaguanfang deposits. Zircon U–Pb and molybdenite Re–Os dating constrains the age of porphyry magmatism and Cu(–Mo) mineralization in the Shan–Zha area to 154–140 Ma (Chen et al, 2023; Luo et al, 2020; Xie et al, 2015, 2017; Zhang et al, 2021). Therefore, the late Mesozoic porphyry(−skarn) Cu deposit in the Shan–Zha area provides a favourable natural laboratory for investigating the formation mechanisms of porphyry Cu deposits in an intra‐continental setting.…”

“…Zircon U-Pb and molybdenite Re-Os dating constrains the age of porphyry magmatism and Cu(-Mo) mineralization in the Shan-Zha area to 154-140 Ma (Chen et al, 2023;Luo et al, 2020;Xie et al, 2015Xie et al, , 2017Zhang et al, 2021). Therefore, the late Mesozoic porphyry(Àskarn) Cu deposit in the Shan-Zha area provides a favourable natural laboratory for investigating the formation mechanisms of porphyry Cu deposits in an intra-continental setting.…”