Geochronology, Geochemistry and Sr‐Nd‐Pb Isotopes of the Early–Middle Jurassic Highly Fractionated Granites in Southern Jiangxi, and their Implications for the Rare‐Earth Mineralization: Examples from the Muzishan, Xiahu, and Zudong Deposits

Abstract Pervasively distributed granitoids in South China contribute greatly to regional polymetallic mineralization, including tungsten, tin, copper, gold, rare metals, and rare earth elements (REEs). To ascertain the dynamic backgrounds, rock types and genesis of the parent rocks related to Early–Middle Jurassic ionic rare earth mineralization, deposits at Muzishan, Xiahu, and Zudong were investigated by conducting petrographic, geochronologic, whole‐rock geochemical, and Sr‐Nd‐Pb isotope analyses, finding that the parent rocks from the Muzishan deposit are an A1‐type K‐feldspar granite (~195 Ma), from the Zudong deposit an A2‐type monzogranite (~171 Ma), and from the Xiahu deposit an I‐type monzogranite (~167 Ma). All three granitic rocks have undergone different degrees of fractionation, with the Xiahu granite experiencing the highest degree, followed by the Zudong granite, and the Muzishan granite undergoing the lowest degree. The Muzishan granite is concluded to have been formed overall under an intraplate extensional tectonic regime influenced by hotspots or a mantle plume. The Zudong granite was formed in a post‐arc extensional setting related to subduction–collision–rollback of the paleo‐Pacific Plate, which caused upwelling of the asthenosphere, thinning of the lithosphere, and partial melting of crustal materials. The Xiahu granite was generated under a transitional tectonic setting of extension and compression, triggered by delamination and rollback of the paleo‐Pacific Plate.