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哀牢山南段蛇绿岩中变质橄榄岩单元,由方辉橄榄岩和二辉橄榄岩组成,前者已强烈蚀变,后者的矿物组成有橄榄石、斜方辉石、单斜辉石及少量尖晶石等。对这些矿物进行了较详细的化学成分分析,橄榄石、斜方辉石的化学成分显示,二辉橄榄岩为较弱亏损的地幔岩;橄榄石、尖晶石的矿物化学反应,变质橄榄岩的原始岩石具有深海橄榄岩的特征;单斜辉石、尖晶石的化学特征显示,二辉橄榄岩经历过部分熔融作用。因此,二辉橄榄岩为部分熔融较弱亏损的地幔
The metamorphic peridotitic units in the southern section of the Ailaoshan ophiolite are composed of the harzburgite and lherzolite, the former has been strongly altered, the latter mineral composition of olivine, orthopyroxene, clinopyroxene And a small amount of spinel. The chemical compositions of these minerals are analyzed in detail. The chemical composition of olivine and orthopyroxene shows that the lherzolites are weaker and weaker mantle rocks, the mineral chemical reactions of olivine and spinel, the metamorphic peridotites Of the original rocks have the characteristics of deep peridotites; the chemistry of clinopyroxene and spinel shows that the lherzolites have undergone partial melting. Therefore, lherzolites are partially melted and depleted mantle