Abstract：Based on the regional geological survey, 4 volcanic depressions and 7 profiles of Cenozoic Hannuoba basalts in Shanxi Province were investigated in this paper. Tholeiitic basalts appear first at the bottom of volcano cycle and upwards are alkaline basalts. Large ion lithophile elements and light rare earth elements are enriched in the rocks. The eruption time is from early to late, magmatic activity becomes weak, tholeiitic basalts decrease, alkaline basalts increase, rare earth and trace elements of sub-alkaline basalts reduce, and rare earth and trace elements of alkaline basalts increase from east to west. Sub-alkaline basalts have Nb and Ta negative anomaly (channel) or twin peaks type in the primitive-mantle normalized spider diagram, which were identified as island arc basalts, while alkaline basalts havs an uplift trend, which are similar to ocean island basalts (OIB). Hannuoba basalts in Shanxi Province is the result of an union action of plate subduction and mantle plume, with the main cause of mantle plume and the auxiliary cause of plate subduction. The transition from sub-alkaline basalts to alkaline basalts may represent the shift of the main reason from plate subduction to mantle plume. The change from potassium to sodium in alkaline basalts, and the evolution of the sub-alkaline basalts to the iron rich magnesium can respectively reflect the process of mantle plume becoming shallow, and plate subduction becoming deep.
2018, Vol. 5 
