苏丹哈佳吉金矿床稀土元素地球化学特征

Geochemistry Characteristics of the Rare Earth Elements in the Alhagagia Gold Deposit,Sudan

通过对苏丹哈佳吉金矿床矿石和围岩稀土元素含量的研究,发现该矿床近矿围岩稀土总量较矿石稀土总量明显要高,轻重稀土元素分馏明显,Eu呈现中等程度或弱的负异常,Ce含量则相对较稳定,表明成矿环境为还原环境。根据近矿围岩的稀土元素C1球粒陨石标准化曲线及北美页岩标准化曲线,可以推断该区古老变质基底所处的构造环境应属大洋岛弧环境,而且在成岩过程中并没有大量海相物质加入。矿石与近矿围岩的稀土配分曲线对比表明矿石中成矿物质既来自变质基底,又有深源物质的参与。

Based on the study about REE content in the Alhagagia gold deposit and its wall rocks in Sudan,it is found that the REE total content of the wall rocks is higher than the ore minerals＇.The fractionation of HREE and LREE is obvious with moderate or slightly negative Eu anomaly and stable content of Ce,which indicates that the ore formed in the deoxidized environment.According to the Chondrite-normalized and NASC-normalized REE patterns of the wall rocks,it is suggested that the metamorphosed basement formed in an oceanic island arc tectonic environment,and there are no much marine facies materials joining in this diagenetic stage.The REE geochemical features of the wall rocks and ores show the ore-forming materials came from metamorphosed basement as well as deep materials.