攀西大陆槽稀土矿床深源成矿流体的稳定同位素证据

Stable Isotope Evidence of Deep Source Ore-forming Fluid in the Dalucao REE Deposit of the Panxi Rift

通过对大陆槽矿床的成矿流体稳定同位素研究表明 ,矿体石英中流体包裹体的δD、δ18O和δ13 C值分别为 - 87‰、+6 .0‰和 - 8.4‰ ,矿石 (氟碳铈矿 )的δ13 C为 - 8.0‰ ,矿体萤石中流体包裹体的δD和δ18O分别为 - 99‰和 - 11.6‰。研究表明 ,矿床的成矿流体应为少量大气降水混合的深源成矿流体 ,流体包体中和矿石中的碳则可能源自较深的壳幔混熔源区。

The features of the ore-forming fluid and the origin of the metallogenic material in the Dalucao REE deposit of Panxi rift were studied by means of H,O and C isotope analyses. The δ 13 C values of the bastnaesite change narrowly from -8.1‰ to -8.0‰ ,while the δD values vary from -89‰ to -79‰. The δD, δ 18 O and δ 13 C of the quartz-fluid inclusions in the orebody are -87‰,+6.0‰ and -8.4‰,whereas he δD and δ 18 O of the fluorite-fluid inclusions in the orebody are -99‰ and -11.6‰,respectively. The study shows that the ore-forming fluid was a mixture of magmatic water and meteoric water. The carbon isotopic features suggest that the carbon in the bastnaesite was derived from the mantle,while the carbon in fluorite-fluid inclusions of the orebody came from a mixed carbon source.