New progress in the metallogenic chronology of the Chishan REE deposit in Weishan County, Shandong Province

Abstract

Objective The Chishan rare earth deposit in Weishan County, Shandong Province is located on the southeastern edge of the North China Plate. It is a magmatic hydrothermal rare earth deposit mainly composed of light rare earths, and is currently the third largest light rare earth deposit in China. There is still controversy over its mineralization age. Methods Therefore, taking the latest exploration borehole ore samples from Chishan rare earth deposit as the research object, the mineralization age of Chishan rare earth deposit was accurately determined through field investigation, mineralogy, and chronology research, using Th-Pb isotope dating of fluorocarbon cerium ore. Results The Th-Pb isotope dating results of 5 fluorocarbon cerium deposits indicate that the mineralization age of the Chishan rare earth deposit can be divided into two periods: the early period is (125.5±0.5)-(122.2±0.5)Ma, and the late period is (112.3±0.6) Ma. Conclusion The early age is basically consistent with the mineralization age of the deposit determined by previous studies, while the late mineralization age is the first report, indicating that there may be two periods of mineralization activity in the Chishan rare earth deposit, which is worthy of attention and further work.

Keywords

• chishan ree deposit
• th-pb dating
• bastnasite
• weishan county
• shandong province