U-Pb Dating of Monazite from the Beryllium Mineralized Pegmatite and Its Geological Significance in the Guyangzhai Area at the Southern Margin of Jiuling,Jiangxi
Taking the beryllium mineralized pegmatite in the Guyangzhai area,southern margin of Jiuling,Jiangxi province as the research object,a significant beryllium mineralized pegmatite vein from the Canglongdong was in-vestigated.Through field geological survey and LA-ICP-MS monazite U-Pb age determination,the geological char-acteristics of granite pegmatites in the Guyangzhai area were preliminarily understood.The results indicate that the beryllium mineralized pegmatites in the Guyangzhai area at the southern Jiuling margin were formed during the ear-ly Cretaceous period,with a precise age of(138.57±0.78)Ma.The beryllium mineralized pegmatite intrudes into the fine-grained porphyritic two-mica monzonite granite of the Guyangzhai pluton that located at the southern margin of Jiuling,slightly later than the Yanshanian Guyangzhai pluton.This finding suggests a close spatial and temporal relationship between the two plutons.It is speculated that the beryllium mineralized pegmatite in the Guyangzhai area was originated from the crystallization differentiation of the two-mica monzonite granite within the Guyangzhai pluton.Therefore,it is recommended to place greater emphasis on investigation within 0~5 km range of the inner and outer contact zones of the Guyangzhai two-mica monzonite granite to facilitate breakthroughs in pegmatite type beryllium ore prospecting in this area.
U-Pb dating of monaziteberyllium mineralized pegmatiteGuyangzhai areasouthern margin of Jiul-ing