Geochemistry and petrogenesis of the permian basalts from Lijian and Ninglang areas, northwestern Yunnan Province, China

The Late Permain basalts, which distributed at Shudiqiao of Lijiang County and Wanmachang of Ninglang County, NW Yunnan Province, display significant enrichment of large ion lithophile elements and high field strength elements that similar to oceanic island basalts. Comparing those basalts with Emeishan high-Ti basalts from Binchuan area, this study suggests that they have the same origin and are resulted from Emeishan mantle plume. Modeling by inversion of rare earth element concentrations has been used to estimate the compositions of source regions and magma evolution of these high-Ti basalts. The results suggest that the basaltic magmas of Shudiqiao and Wanmachang are consistent with the extraction of a melting fraction of 2% - 3% from a transition region (with spinel: garnet ranges from 0.65: 0.35 to 0.5: 0.5) and experienced fractional crystallization of 5% - 15%,and from a melting fraction of 3% from a simialr region (with spinel garnet: 0.45 0.55 - 0.5: 0.5) and underwent 5% fractional crystallization respectively.