Spatiotemporal reconstruction of Late Mesozoic silicic large igneous province and related epithermal mineralization in South China: Insights from the Zhilingtou volcanic‐intrusive complex

Abstract

Silicic large igneous provinces (SLIPs) generally reflect large‐scale melting of lower crustal materials and represent significant metal reservoirs. The South China Block‐Coastal Region (SCB‐CR) SLIP hosts several large epithermal deposits. To better understand these deposits, we document the spatiotemporal framework of the host SLIP across the SCB‐CR. Using zircon U‐Pb dating and geochemical and isotopic analysis, we identify four stages of emplacement. Stage 1 felsophyre (circa 149 Ma) shows a chemical affinity to highly fractionated I‐type granites. Stages 2 and 3 of low‐Mg felsic volcanics (circa 128 to 111 Ma) and stage 4 felsite (circa 100 Ma) have higher εHf(t) and εNd(t) values than stage 1 felsophyre, suggesting a significant contribution of newly underplated juvenile crust to the magma sources. Stage 4 diabase (circa 101 Ma) was likely produced by melting of subduction˗metasomatized asthenospheric mantle. Together with reliable published data, we build a new spatiotemporal framework of volcanics and infer that the majority of the SCB‐CR SLIP was related to the gradual northwestward subduction of the Izanagi plate beneath South China in a continental arc setting during circa 170 to 110 Ma, and minor contribution was from the eastward retreat of the subducting slab in a back‐arc setting during circa 110 to 90 Ma. We conclude that the large‐scale epithermal mineralization was generated by melting of the metal‐rich, thin (30–40 km), newly underplated hydrous juvenile crust during the tectonic transition from arc to back‐arc settings.

Geochronology, geochemistry, and petrogenesis of the late Mesozoic Luoyang volcanics: Implications for the geodynamic evolution of the Zhejiang–Fujian region, SE China

“…There is a broad zone of younger volcanics (140–120 Ma) across eastern Fujian and all of Zhejiang (Figure ), which is consistent with the 140–110 Ma province proposed by Wang et al (). Coeval mafic dikes also occur in this region (Figure ), which is strongly suggestive of a back‐arc setting, rather than the continental arc setting proposed by Wang et al (). We propose that the late Yanshanian rhyolite porphyries, LY‐2 and LY‐3, formed in a back‐arc setting that was related to the rollback of the subducting Paleo‐Pacific Plate.…”

“…Many researchers have described a model involving subduction of the Paleo‐Pacific Plate to explain the tectonic evolution of SE China during the Mesozoic (Jiang, Bagas et al, ; Li & Li, ; Liu, Xu et al, , Liu, Yu et al, ; Jiang, Bagas et al, ; Jiang, Wang et al, ; Liu, Xu, & Xia, ; Sun, Ding, Hu & Li, ; Wang et al, ; Wang & Shen, ; Zhou, ; Zhou et al, ; Zhou & Li, ). Some authors have proposed that the early Yanshanian granitoids were generated in an extensional setting, whereas the late Yanshanian granitoids were formed in a continental arc setting, both related to subduction of the Paleo‐Pacific Plate (Li & Li, ; Zhou et al, ).…”

“…Some authors have proposed that the early Yanshanian granitoids were generated in an extensional setting, whereas the late Yanshanian granitoids were formed in a continental arc setting, both related to subduction of the Paleo‐Pacific Plate (Li & Li, ; Zhou et al, ). However, Wang et al () argue that the Middle Jurassic to Early Cretaceous volcanics were formed in a continental arc setting related to the initial northwestward subduction of the Izanagi Plate beneath SE China, whereas Late Cretaceous bimodal volcanics formed in a back‐arc setting caused by subsequent slab rollback.…”

“…The age data of volcanics and I‐type granites (160–140 Ma), volcanics, A‐, I‐type granites and mafic dikes (140–120 Ma) are from Cao et al (); Ding (); Guo et al . (); Li, Zhou, Chen, Wang, and Xiao, (); Liu et al (), Liu et al (); Liu et al (); Liu et al (); Wang et al (); Wang et al () and Wong et al (); Xiang (); Zhang (); Zhang et al (); Zhao (); Zhao (); Zhou (). ① = Jiangshan–Shaoxing fault zone; ② = Zhenghe–Dapu fault zone [Colour figure can be viewed at wileyonlinelibrary.com]…”

Petrogenesis of two stages of Cretaceous granites in south‐west Fujian Province: Implications for the tectonic transition of South‐east China

“…It is commonly accepted that southern China records two major tectonic events during the Mesozoic, namely, Indosinian tectonism related to the paleo‐Tethyan tectonic system (Carter, Roques, Bristow, & Kinny, ) and Yanshanian activity related to paleo‐Pacific tectonism (Jahn et al, 1976; Zhou et al, 2006a). However, the tectonic setting of Mesozoic magmatism in South China remains controversial (e.g., He, Xu, & Niu, ; Li & Li, ; Li, Chen, Liu, & Li, ; Mao et al, ; Wang, Wyman, et al, ; Wang, Xu, et al, ; Wang et al, ; Zhou & Li, ; Zhou, Sun, Shen, Shu, & Niu, ), with some research favouring model involving roll‐back and a change in the subduction angle (Zhou & Li, ), westward‐directed flat subduction (Li & Li, ), subduction direction changes (Wang et al, ), or ocean‐ridge subduction (Sun, Ding, Hu, & Li, ; Sun et al, ).…”