胶北地体早前寒武纪地层的稀土演化特征

THE REE EVOLUTION CHARACTERISTICS OF EARLY PRECAMBRIAN STRATIGRAPHY IN JIAOBEI TERRANE

胶北地体早前寒武纪地层分三部分：即太古宙胶北群（Ａｒ，＞２５５０Ｍａ），属第一期绿岩；早元古代早期齐山群（Ｐｔ（１－１），２５５０－２３００Ｍａ），属第二期绿岩和早元古中期荆山－粉子山岩系（Ｐｔ（１－２），２３００－２０５０Ｍａ），相当于孔达岩系。本文研究了它们的稀土特征，讨论了这三群副片岩类和基性－中酸性火山岩类各自的稀土演化特征，为齐山群和荆山－粉子山岩系的建立提供了依据。

The REE characteristics of Early Precambrian stratigraphy in the J iaobei terrane can be summaried as follows: the gneissoid rocks of the Jiaobei Group have lower REE contents and higher ratios of LREE/HREE and belong to typical TTG rocks; the paraschists at the bottom of Qishan Group have higher REE contents and ratios of LREE/HREE with strong negative Eu anomaly, which is typical of postArchean paraschist; the Jingshan Group and Fenzishan Group have identical REE.characteristics, and formed the Jingshan-Fenzishan Series. The REE distribution of Archean metatholeiite is consistent with that of the TH2 formed in the ocean environment, and REE distribution of Proterozoic metatholeiite is consistent with TH1 formed in the island arc. According to these, the evolution history of Early Precambrian Era in the Jiaobei terrane and the stratigraphy division are discussed in this paper. The Early Precambrian stratigraphy in the Jiaobei terrane can be divided into 3 parts: the Archean Jiaobei Group (Ar,>2550Ma), being the first-stage greenstone; the Qishan Group in the lower part of Early Proterozoic (pt_(1-1),2550-2300-2300Ma),being the second-stage greenstone;and the Jingshan-Fenzishan Series in the upper of Early Proterozoic (Pt_(1-2), 2300-2050Ma), similar to Khondalite Series.