冀北赤城雾迷山组硅质岩地球化学特征及沉积环境  

Geochemical Characteristics of Siliceous Rocks in Wumishan Formation of Northern Hebei

作　　者：郑秀才[1] 

机构地区：[1]长江大学工程技术学院,湖北荆州434020

出　　处：《石油天然气学报》2011年第6期53-58,7,共6页Journal of Oil and Gas Technology

基　　金：中国石油化工股份有限公司海相前瞻性研究项目(YPH08026)

摘　　要：冀北赤城雾迷山组发育的硅质岩属于低硅质含量硅质岩,其SiO2平均含量为83.76%。岩石Al2O3含量(平均0.03%)和TiO2含量(平均0.01%)相对较低,MgO含量(平均3.65%)相对于Al2O3和TiO2含量较高,但明显与SiO2呈负相关。Fe/Ti、(Fe+Mn)/Ti、Al/(Al+Fe+Mn)比值,Al-Fe-Mn、Fe/Ti和Al/(A1+Fe+Mn)的图解都显示区内硅质岩具有明显的热水沉积的特征;MnO/TiO2比值,Fe2O3/TiO2和Al2O3/(Al2O3+Fe2O3)双变量图解判别显示硅质来源于大洋中脊;CaO/(Fe+CaO)、(MgO/Al2O3)×100比值指示出其形成于高盐度环境。The siliceous rocks in Wumishan Formation of Northern Hebei are characterized by low content of the siliceous rocks with average content of 83.76%,the major elements such as Al2O3(the average content of 0.03%)and TiO2(the average content of 0.01%),were low and MnO(the average content of 3.65%) was higher,and was negatively correlated with SiO2.The ratios of Fe/Ti,(Fe+ Mn)/Ti,Al/(Al+Fe+Mn) and Al-Fe-Mn diagrams show that the siliceous rocks are the sedimentary rocks of hydrothermal origin.From the MnO/TiO2 ratios,and Fe2O3/ TiO2-Al2O3/(Al2O3+ Fe2O3) diagrams,the hydrothermal system are mainly distributed in the tensile environment such as MOR,Arc-rear basin,Aulacogen and so on.The ratios of CaO/(Fe+CaO) and MgO/Al2O3×100 show that the seawater during the deposition of the siliceous rocks in the Wumishan Formation in northern Hebei might be freshened.

关 键 词：硅质岩 热水沉积 地球化学 沉积环境 雾迷山组 冀北 

分 类 号：P588.2[天文地球—岩石学]