关键词: 富铝尖晶石, 成分, 元素分异, 相关性

Abstract: The lherzolite, wehrlite and pyroxenolite are three main kinds of xenoliths in Yitong upper mantle shear belt, Northeastern China. Spinels in the xenoliths are characterized by aluminumenriched in compositions. The spinels in pyroxenite xenoliths are aluminum spinel with higher Al content and lower Cr content and green in color in thin sections. Compared with it, the spinels in lherzolite and wehrlite xenoliths are aluminumenriched chrome spinel with relatively lower Al content and higher Cr content and brown in color in thin sections. The color of the spinels are related to Al,Mg and Cr,Fe contents. The compositions of the spinels in the different xenoliths have their own variable ranges and have some correlations one another. The obvious negative correlations between Mg# and Cr#，Mg# and Fe2+, Cr and Al, and the positive correlation between Mg# and Al# reflect that those spinels were derived from a same source and have relationships in genesis. The differentiation between Al and Cr is obvious in the processes of partial melting and crystallization. The variations basically obey the relation of octahedral Cr[CD*2]Al substitution in the solid[CD*2]solution condition. Differences in the spinel compositions may be the results of differentiation in the processes of partial melting and crystallization and ion substitution in the solid[CD*2]solution.

Key words: aluminum enriched spinel, composition, element differentiation, correlation