冀北崇礼红旗营子黑云斜长片麻岩的地质地球化学特征

基于当代红旗营子群是否应该解体这一观点，研究了崇礼红旗营子群中黑云斜长片麻岩的地质地球化学特征。研究表明原岩为泥质沉积岩，其特点为SiO2〉56％，Al2O3〉MgO，Na2O〉K2O，Na2O／（Na2O＋K2O）〉0．5，且其他氧化物与SiO2含量呈现出有规律的变化，随着岩石中SiO：含量的增加，TiO2，AL2O3，FeO，Fe2O3，MgO，CaO，Na2O和K2O呈明显下降趋势。稀土元素总量较低；轻重稀土分离程度较高，LREE／HREE的值为5．16～7．98，La。／Yb。的值为4．28～8．62，轻稀土富集，重稀土平坦分布，稀土配分曲线表现出中等程度的负Eu异常，δEu的值为0．73～0．83。稀土元素Ce基本无异常或略显负异常，表明其形成环境可能为一浅海相或边缘海或被陆地封闭海。

The Geological and Geochemical Characteristics of Biotite Plagioclase Gneiss from Hongqiyingzi Group in the Chongli County,Northern Hebei Province

This paper gives a systematic study of the geological and Geochemical characteristics of Biotite plagiogneiss from Hongqiyingzi Group in the Chongli. The results show that their protolith are politic sedimentary rock, the characteristics is SiO2 〉56% ,Al2O3 〉 MgO,Na2O 〉 K2O,Na2O/（ Na2O ＋ K2O） 〉 0.5, the content of other oxide and SiO2 shows regular changes, as the content of SiO2. In the rock increase, TiO2, Al2O3, FeO, Fe2O3, MgO, CaO, Na2O and K2O present a downward trend obviously. The total REE values are not very high, the degree of separation of LREE and HREE are relatively high, the ratio of LREE/HREE are 4.28 - 8.62, displaying LREE - enriched and HREE - flattened patterns, the distribution curve of REE shows intermediate negative Eu anomalies and weak negative Ce anomalies, the chondrite - normalized Eu/Eu ＊ values are 0.73 - 0.83, which indicate that the forming environment maybe neritie facies or marginal sea or Enclosed sea by land.