U-Pb Dating of Zircons and Ore-bearing Potential of Zhulanbu Intrusions in the Southern Jiangxi Province

Zhulanbu granite is located in the Nanling district with a large exposed area, but its formation age is still unknown. It was previously considered to have formed at the Yanshanian, but no precise isotopic age was reported, as a result of the limitation of time and method. LA-(MC)-ICPMS was used to determine the ages of zircons from coarse grained prophyritic bioxite granite and medium-fine grained prophyritic biotite granite, which were used to discuss the ore potential, and is reported here. These two types of rocks have ages of 228.7±2.0 Ma and 231.0±1.2 Ma, indicating Zhulanbu composite granite was formed in Indosinian. Combined with the geochemistry of Zhulanbu composite granite and ore-forming characteristic of Indosinian granite, these ages explain the phenomenon that tungsten deposits are not found within the granite and its surroundings. This study provides a new example for the study of granite in southern Jiangxi.