The amalgamation process and suture boundary of the Yangtze and Cathaysia blocks have been in hot dispute and attracted considerable attention. Overall, controversies remain on where the closure boundary of the Paleo-Huanan Ocean was and how the Jiangshan-Shaoxing fault southwesterly extended. This paper presents a set of new geochronological, geochemical and Nd isotopic data for the igneous rocks from the Zhoutan and Shenshan groups in Central Jiangxi. The Zhoutan amphibolites formed during the Neoproterozoic (∼850–830 Ma) and experienced the Silurian (∼430 Ma) metamorphism. They have low SiO2 (49.5–52.9 wt%), Al2O3 (13.48–14.38 wt%), and TiO2 (0.99–1.57 wt%) contents and K2O/Na2O values (<1.0), and show E-MORB-resembling REE and PM-normalized pattern, with Nb/La of 0.59–0.88. Their εNd(t) values range from + 4.8 to + 5.9, and they were originated from a slab fluid-modified E-MORB-like mantle source. The high-Mg meta-andesite and -dacite rocks from the Zhoutan Group and Lower Shenshan subgroup yield zircon U–Pb mean ages of 850–837 Ma and exhibit 61.4–75.2 wt% SiO2 and 2.0–4.1 wt% MgO. They are enriched in LILEs and depleted in HFSEs, with Nb/La = 0.21–0.42 and εNd(t) = − 3.1 to − 8.9. These high-Mg volcanic rocks were derived from a sediment- modified wedge source. The Shenshan Group is likely to be an equivalent of the Yingyangguan volcano-sedimentary sequence that was split into Lower (853–830 Ma) and Upper (810–740 Ma) subgroups. The Zhoutan and Lower Shenshan igneous rocks formed in a fore-arc setting at the Neoproterozoic period in response to the westward consumption of the Paleo-Hunan Ocean. The Jiangshan–Shaoxing suture extends southwardly into the Yingyangguan area across the Zhoutan–Yangtian area near to the Chenzhou-Linwu fault.
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