辽西元古宙旧庙基性杂岩的地球化学特征及物源区讨论

GEOCHEMICAL CHARACTERS AND SOURCE REGION OF PROTEROZOIC JIUMIAO BASIC COMPLES IN WESTERN LIAONING PROVINCE

辽西旧庙基性杂岩主要由二辉辉石岩、辉长苏长岩和角闪辉长岩组成。它们是由同源岩浆演化分离结晶作用为主形成的拉斑玄武系列。痕量元素、ＲＥＥ及Ｓｒ同位素的特征表明岩浆起源于富集型地幔源区。低的Ｎｉ、较高的Ｈ２Ｏ，说明初始岩浆起源于富含Ｈ２Ｏ的富集型地幔源区，在相对较低的温度下熔融形成。ｗ（Ｒｂ）／ｗ（Ｂａ）、ｗ（Ｒｂ）／ｗ（Ｓｒ）值变化较大。

The Jiumiao basic complex in Western Liaoning Province is mainly composed of websterite, gabbro-norite and bojite, which belong to tholeiite series derived from comagma by fractional crystallization. Data on trace elements, REE and isotope Sr indicate that the magma come from enriched mantle. Low value of Ni and high content of H 2O suggest that original magma be formed by partial melting of low-temperature part in mantle enriched water. Varying values of w (Rb)/ w (Ba) and w (Rb)/ w (Sr) suggest that original magma be highly mixed with materials of lower crust during evolution.