相山两种不同成因角闪石的地球化学特征对比

通过详细研究相山两种不同成因角闪石的元素及同位素地球化学发现：江西相山铀矿田北部同时存在两种不同成因的角闪石：正变质成因的角闪石，寄主岩石为斜长角闪(片)岩，微量元素以富集大离子亲石元素(LILE)(K,Rb，Th，Ta，U)、稍为富集Ti,Se和相对贫高场强元素(HFSE)(Zr，Hf,Y，Yb，Cr，HREE)为特征，稀土总量低，稀土分布型式为近水平型，δ^18O为7．95～8．58，显示变质火成岩的氧同位素特征；副变质成因的角闪石，寄主岩石为含石榴角闪石英片岩．微量元素以高度富集大离子亲石元素(LILE)(K，Rb，Th，U)、稍为富集Ta,Nb，Ce，Zr，Hf，Sm和相对贫高场强元素(HFSE)(Ti，Y，Yb，Cr)、强烈亏损Sc为特征，稀土总量高．轻重稀土相互分离程度高，轻稀土富集，O同位素组成(δ^18O)较高，为9．95～10．02，显示碎屑沉积变质岩的氧同位素特征。

THE COMPARISON OF ELEMENT AND ISOTOPE GEOCHEMICAL CHARACTERISTICS OF TWO KINDS OF GENETIC AMPHIBOLTES FROM NORTH XANGSHAN

In this paper, element and isotope geochemistry of two kinds of genetic amphibole are studied. The research result shows there are two kinds of genetic amphibole from north Xiangshan U-ore field in Jiangxi Province. i.e.,the ortho-metamorphic genetic amphibole with its host-rock being amphibolites(schist) and the para-metamorphic genetic amphibole with its host-rock being amphibolite quartz-schist. There are obvious differences in mineral species, petrochemistry, trace element and REE geochemistry, oxygen isotope compositions and metamorphic grade.Ortho-metamorphic genetic amphibole exhibits patterns characterized by enrichment in LIL elements(K,Rb,Th,Ta,U), slight enrichment in Ti, Sc and relative depletion in HFSE( Zr,Hf,Y,Yb,Cr,HREE), and by depleted LREE, concave-up,patterns.Para-metamorphic genetic amphibole exhibits patterns characterized by strong enrichment in LILE (K,Rb,Th,U), slight enrichment in Ta,Nb,Ce,Zr,Hf,Sm and relative depletion in HFSE (Ti,Y,Yb,Cr),strong depletion in Sc,and displays clear LREE-enriched patterns with high La_N/Yb_N ratios.