本文对北祁连熬油沟蛇绿岩中的辉石、长石、铬铁矿和铁钛氧化物的成分进行了研究 ,结果表明 ,铬铁矿具有高的 Al、Mg含量和低 Fe3 + 及 Cr含量 (Cr* 值为 0 .4 8～ 0 .4 9)的特点 ,反映了其形成于大洋中脊下的低熔地幔。辉石、铬铁矿和铁钛氧化物中 Fe3 + 的含量均较低 ,表明这些矿物的分离结晶作用是在低氧逸度条件下进行的 ,因而熬油沟蛇绿岩中的玄武质岩石均不是初始岩浆 ,而是分离结晶以后形成的残余岩浆 ,其初始岩浆可能为更加富镁和铬的苦橄质岩浆 In this paper, the compositions of pyroxene, feldspar, chromite and iron-titanium oxide in the AoYugou ophiolite from North Qilian were studied. The results show that the chromite has high contents of Al, Mg and low Fe3 + And Cr content (Cr * value of 0.848 ~ 0.49), reflecting the formation of low-melting mantle beneath the mid-ocean ridge. The contents of Fe3 + in pyroxene, chromite and iron-titanium oxide are low, indicating that the crystallization of these minerals is carried out under low oxygen fugacity conditions, and the basaltic rocks in the Aoyougou ophiolite Are not the original magma, but the residual magma formed after the separation crystallization, the initial magma may be more magnesian and chromium bitter olivine magma