Geochemical Characteristics of Rocks From Qingshuigou of Middle Qilian Ophiolete by NAA

A content of REE in harzburgite from Qingshuigou ophiolete are determined by preconcentration neutron activation analysis，contents of REE in basalts are measured by instrument neutron activation analysis ，according to geochemical Characteristics of REE. The results indicat that harzburgite （Q1, Q11, Q12）are refractory residue left after partial melting of the upper mantle; tholeiite（Q3, Q6, Q10, Q2, Q4, Q8）are derived from partial melting of a LILE-rich mantle wedge overlying the subduction zone. Therefore，the Qingshuigou ophiolites may be the product of island-arc volcanic activity，and probably generated in the fore-arc or back-arc tectonic settings