U-Pb Dating of Zircon from Jibu Huangsha Intrusions in Southern Jiangxi Province and Its Geological Significances

Jibu Huangsha granitic intrusions in Southern Jiangxi province hosted several ion adsorption type rare earth element (REE) deposits, but it's diagenic age is still unknown. In this paper, the U-Pb age of zircon separated from the weathering crust of Jibu Huangsha granitic intrusions was dated by using Laser Ablation-Multicollector Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICPMS). The dating results show that the weighted average ²⁰⁶Pb/²³⁸U age is (242.5±1.8) Ma, which indicates that the Jibu Huangsha intrusion formed in the early Indo-Chinese epoch, instead of the Yanshan epoch as suggested in the geological report of the Xingguo unit in a scale of 1/200000. Combining with the reports of other Indosinian granites in the Nanling district, it was concluded that Indo-China movement had a great effect in the Nanling district and produced larger scale magmatic activity with more outcrop areas than was previously understood. The higher latitude of Huagnsha intrusion further indicated the intrusions described in the geological report of Xingguo, Jinggangshan, and even the Ninghua unit in a scale of 1/200000 also have the potential to host ion adsorption type REE deposits, which should be significant for ore prospecting.