| Abstract:Kimberlites have been found in eight provinces of China, namely Liaoning, Shandong, Guizou, Henan, Hubei, Shanxi, Hebei and Jilin, all located in North China platform and Yangtze platform; nevertheless, only kimberlites in Shan-dong and Liaoning provinces contain diamonds of economic significance. Isotopic dating and geological data reveal that kimberlites in China mainly occur in Paleozoic. In Guizhou, Hubei and Shanxi, kimberlites with very little or no diamonds are associated with lamproite, meymechite and minette. Kimberlite pipes observed at surface of Shandong and Liaoning are root facies and bottom facies of diatreme respectively.Diamond-bearing kimberlites are richer in MgO+Cr2O3+NiO but poorer in TiO2+A12O3+2Na2O+K2O+P2O5 as compared with diamond-free ones. The average content of compatible elements in kimberlites of China is Cr 846 ppm, Ni 690 ppm, Co 45 ppm, Sc 19.96 ppm, Cu 156 ppm and Zn 106 ppm and that of incompatible elements Ba 835 ppm Sr 454 ppm, Zr 308 ppm, Nb 81 ppm, Ta 11 ppm, U 8.8 ppm, Th 70 ppm, Li 44.68 ppm and Rb 29 ppm. Lots of element pairs in kimberlites, i.e. Cr-AI, Ni-Co, Ni-Cr, Ni-V, Sc-Ti, Zn-Ti, Ba-Sr, Zr-Hf, Nb-Ta, U-Th and K-Rb, show positive correlation.In diamond-rich kimberlites, pyrope and chrome-spinel are rich in Cr but poor in Al, ilmenite contains high Mg and Cr, clinopyrixene has high Mg and Cr but low Ca and Fe, and olivine shows high Mg content. |
