Sulfides in mantle xenoliths of Cenozoic basalts from Liuhe, Jiangsu province, China.

Mantle xenoliths captured in alkali-basalt occurs widely in the Liuhe distr ict, Jiangsu province, China, dominantly by spinel Iherzolite. Sulfides are commonly found in minerals of the mantle xenoliths. They occur as: (1) ear ly sulfide grains captured by host minerals; (2) intergranular or filling i n the fissures; and (3) sulfide-melt inclusions, including one phase sulfid e inclusions, sulfide-glass two phase melt inclusions, and CO2-sulfide-glas s (sometimes containing silicate daughter minerals) poly-phase melt inclusi ons. Electron microprobe analysis shows that sulfide-melt inclusions have h igher Fe and S contents and lower Ni content than sulfides in fissures do. The molar ratios of Ni to Fe, r(Ni)/r(Fe), of sulfide-melt inclusions range from 0.14 to 1.73, generally from 0.70 to 1.55, while those of intergranul ar sulfides range from 1.76 to 7.03. Like that of Liuhe, sulfide-melt inclu sions in Hannuoba (Hebei province), Xinchang (Zhejiang province) and Qilin (Guangdong province) have higher Fe and S contents and lower Ni content whe n compared to intergranular sulfides. For both sulfide-melt inclusions and intergranular sulfides, S contents increase from Liuhet Xinchang, and Hannu oba to Qilin, Fe contents increase from Liuhe, Xinchang, Qilin, to Hannuoba ; while Ni (+Co) contents decrease from Liuhe, Xinchang, Qilin, to Hannuoba . It is indicated that there is a close relationship between intergranular sulfides and sulfide-melt inclusions.