Geochemical characteristics of Hongling biotite granite and ion-adsorbed rare earth deposits in Shaoguan,Guangdong
China is rich in ion-adsorbed rare earth deposits and their extensive study can help secure key metal resources for the country.In this study,we analyze the weathered crust section of the newly discovered ion-adsorbed rare earth deposit in the Hongling area of Shaoguan,in the Guangdong Province of China,and examine the fresh granite,trace elements,and zircon U-Pb chronology of the whole-rock major elements.The aim is to identify the geochemical characteristics of the ore-forming bedrock and the mechanism of enrichment of rare earth elements in the weathered crust.The zircon U-Pb age of Hongling biotite monzonite was(162.0±0.5)Ma,which is consistent with the metallogenic age of tungsten-tin rare metals in the Nanling area.The Hongling granite had high contents of SiO2(average,73.73％),Al2O3,K2O,and A/CNK(average,1.2),and was classified as calc-alkaline magmatic rock.This,combined with the characteristics of the trace elements,led us to determine that the Hongling pluton had originated from S-type granite formed by the partial melting of metasedimentary rocks in the lower crust.The Hongling granite also had a high content of rare earth elements(average,225.3 × 10-6),which constitute a high-quality source for the formation of ion-adsorbed rare earth minerals.The content of rare earth elements increased from low to high,and then decreased from the topsoil layer,the upper part of the total regolith,and the lower part of the regolith to the semi-regolith.The content of rare earth elements in the regolith was relatively high on the whole,with an average value of 608.9 × 10-s.The average ratio of light to heavy rare earth elements was 5.5,and they were classified as enriched and light rare earth elements.The rare earth elements in the regolith of the Hongling area had inherited the geochemical characteristics of fresh Hongling granite.The latter had a high content of rare earth elements,while the high chemical alteration index of the regolith suggests that the study area had good ore-prospecting potential for ion-adsorbed rare earth deposits.
biotite graniteion-adsorbed rare earth element depositspetrogenesisNanlingShaoguan,Guangdong Province
万方数据
维普
