Geochemical Characteristics of Rare-Earth Elements of Guidong Granitic Complex and Relationship with Uranium Mineralization

Abstract

Some of the granite-type uranium deposits just located nearby the low temperature geothermal system, hot spring system in China. So the study of the mineralization system would be helpful for the understanding of the geothermal system. Granites rich in uranium and other lithophile elements are a potential source of shallow heat energy through enhanced geothermal development. Guidong granitic complex is consists of the Luxi intrusion, Xiazhuang intrusion, Maofeng intrusion, Sundong intrusion, Aizi intrusion and Siqian intrusion, which were emplaced in the Indosinian and early Yanshanian Periods. These intrusions varied from each other not only in major element content, aluminium saturation index, but also in values of ∑REE, δEu, and LREE/HREE, (La/Yb)N, (La/Sm)N and (Gd/Yb)N. The Maofeng intrusion, which has the closest relationship with uranium mineralization, belongs to peraluminous granite family. Having undergone much intense fluid-rock interaction, it is characterised by typical M-type tetrad effects and lowest values of ∑REE, δEu, LREE/HREE, (La/Yb)N, (La/Sm)N and (Gd/Yb)N ratios than other studied intrusions.