Geochemical, zircon U–Pb–Hf, and whole‐rock Sr–Nd isotopic study of Late Jurassic Sanming A‐type granite in the Wuyi area, Fujian province, Southeast China

Abstract

The Sanming pluton is the only Late Jurassic A‐type granitic intrusion in the Wuyi area, west Fujian Province, Southeast China, and its formation has important implications for our understanding of the tectonic evolution of the region. The U–Pb ages of 157 ± 1 Ma and 159 ± 1.1 Ma were obtained for the pluton by zircon LA–ICP–MS analysis, which is interpreted to be the crystallization age of the Sanming pluton (i.e., Late Jurassic). The pluton has the geochemical characteristics of A‐type granite, such as high K2O+Na2O contents (average 7.703 wt%), FeOT/(FeOT + MgO) ratios (average 0.85), and high 10,000 Ga/Al values and Zr + Nb + Ce + Y (380–446.1 ppm, average 419.2 ppm) contents, but relatively low CaO, Sr, and Eu contents. Zircon saturation temperatures range from 875 °C to 890 °C, also similar to other A‐type granites. The (87Sr/86Sr)i ratios (0.707368–0.71102) and εNd(t) and εHf(t) values (−5.54 to −6.09, and −6.93 to −1.07, respectively), the 2‐stage Nd model ages of 1.50–1.55 Ga, and 2‐stage Hf model ages of 1.25–1.62 Ga, suggest the pluton was derived by extensive fractionation of melts containing both mantle materials and Mesoproterozoic crustal components. The Sanming A‐type granitic pluton is younger than adakitic rocks in the region (162 Ma), suggesting a localized transition from compressional to intraplate extensional tectonics at 162–159 Ma, with mantle‐derived material playing a crucial role in the formation of A‐type granites in the Wuyi Mountain area. This tectonic transition is explained by localized rollback of the subducting Pacific plate.

Early Paleozoic oceanic slab subduction in South China: Evidence from adakite‐like granodiorite and high‐Mg diorite from Puyang pluton in the Wuyi orogenic belt

“…All zircon grains show clear oscillatory zoning, which is consistent with a magmatic origin. And they show very high Th/U ratios (all >0.5), similar to typical magmatic zircons (Belousova et al, 2002; Hoskin & Schaltegger, 2003; Wu & Zheng, 2004; Zhao, Jiang, Yu, et al, 2017; Zhao, Yu, Mao, et al, 2017). RTW3436‐1: Zircon grains from samples RTW3436‐1 show very clear and narrow oscillatory zoning, similar to magmatic zircons.…”

“…They exhibit strong negative Nb, Ta and Ti anomalies and positive Zr and Hf anomalies on the primitive‐mantle normalized trace element spider diagrams (Figure 5b). The strong negative Nb–Ta and Ti anomalies normally indicate the high crystallization of the Ti‐bearing minerals, including ilmenite, rutile, and titanite (Foley et al, 2002; Green, 1995; Manning & Bohlen, 1991; McDonough, 1991; Rudnick et al, 2000; Zhao, Jiang, Yu, et al, 2017).…”

Records of Nanhua island arc activity between the north and south Wuyi terranes in the Cathaysia Block

“…Previous studies reported that the North Wuyi terrane collided and merged with the East Wuyi terrane at 450–440 Ma (e.g., Zhao et al, 2017, 2019; Zhao, Jiang, Xing, et al, 2018; Zhao, Jiang, Yu, et al, 2018; Zhao, 2022). However, the detailed evolution between the North and South Wuyi terranes remains controversial and understated.…”

Mesozoic multi‐stage W–Sn polymetallic mineralization in the Nanling Range, South China: An example from the Dengfuxian–Xitian ore field

“…Mesozoic large‐scale magmatism and associated ore formation in South China peaked during three intervals: at ca. 230–210 Ma, 160–150 Ma, and 90–70 Ma (Feng, Zhang, Zeng, & Wang, ; Hu & Zhou, ; Li et al, ; Mao et al, ; Wang et al, ; Zhao, Jiang, Yu, Xing, & Yu, ). Compared to the well‐studied Jurassic ore‐forming events, the Late Triassic and Late Cretaceous mineralization stages have been less thoroughly investigated to date, especially in the Nanling Range (Chen, Wang, Zhu, Lu, & Ma, ; Wu et al, ).…”

“…Mesozoic large-scale magmatism and associated ore formation in South China peaked during three intervals: at ca. 230-210 Ma, 160-150 Ma, and 90-70 Ma (Feng, Zhang, Zeng, & Wang, 2012; FIGURE 1 Distribution of Mesozoic granites in South China (after Cai et al, 2015), showing the location of the Dengfuxian and Xitian ore fields [Colour figure can be viewed at wileyonlinelibrary.com] Zhou, 2012;Li et al, 2016;Mao et al, 2013;Wang et al, 2011;Zhao, Jiang, Yu, Xing, & Yu, 2017). Compared to the well-studied Jurassic ore-forming events, the Late Triassic and Late Cretaceous mineralization stages have been less thoroughly investigated to date, especially in the Nanling Range (Chen, Wang, Zhu, Lu, & Ma, 2014;Wu et al, 2012).…”