Fluid composition and carbon & oxygen isotope geochemistry of Cenozoic alkali basalts in eastern China

The fluid compositions of Cenozoic alkali basalts in eastern China have been determined by the pyrolysis-MS method, meanwhile the carbon and oxygen isotopic compositions of CO^sub 2^ released from these samples at different heating temperatures have been analyzed by the vacuum step-heating method. The data show the volatile heterogeneity in upper-mantle sources and different evolution trends of alkali basaltic magmas in eastern China, and these alkali basaltic magmas may be generated in the oxidizing milieu, as compared with mantle-derived xenoliths in these alkali basalts, and exotic volatile components were mixed into these magmas in the process of their formation and development.[PUBLICATION ABSTRACT]