大别杂岩内角闪质岩石的稀土元素特征及其成因

REE CHARACTERISTICS AND PETROGENESIS OF AMPHIBOLITES IN THE DABIE COMPLEX

大别杂岩内角闪质岩石呈透镜状或似层状产出,由10种不同岩类构成。根据稀土元素特征,可把角闪质岩石分为轻稀土富集型和平坦型两大类。稀土元素的定量模拟表明,它们是由上地幔石榴二辉橄榄岩经20%的部分熔融和35—56%的橄榄石(TH1型)和14—20%的橄榄石和单斜辉石(TH2型)的分离结晶形成的。

Stratoid or lenticular amphibolites in the Dabie Complex are consist of ten types.Basedon their REE features,the amphibolites are divided into two types,i.e.,one is characterized byflat REE distribution patterns and the other by LREE-enrichment.Results of the REE quan-titative modelling suggest that the amphibolites were formed from 20% partial melting of gar-net lherzolite and 35—56% fractional crystallization of olivine(type TH1)or 14—20% frac-tional crystallization of olivine and clinopyroxene(type TH2).