Trace Element Geochemistry of Cenozoic Volcanic Rocks in Shandong Province

<正> The Cenozoic volcanic rocks of Shandong Province are mainly alkatic and strongly alkalic basalticrocks.The contents of major and trace elements including transitional,incompatible and rare-earth ele-ments were determined.The chemical characteristics of major and trace elements indicate that these basalticrocks were derived from a mantle source and probably represent a primary magma,i.e.,unmodifiedpartical melts of mantle peridotite,in terms of Mg values,correlations between P2O5 and Ce,Sr,Niand Rb concentrations,mantle xenoliths,etc.The abundances of trace elements vary systematically fromwest to east.The compatible transition elements such as Co,Ni,and Cr show a remarkable deple-tion,whereas the incompatible and rare-earth elements are abundant as viewed from the chondrite-nor-malized patterns.The chemical composition and correlation are consistent with the tectonic setting.According to the batch and fractional partial melting theory,the trace elem（?）nt contents of Shandongvolcanic rocks can be calculated from the two-component mixing model.