摘要
通过对白云鄂博富钾板岩的岩石学、矿物学及岩石化学的研究,提出富钾板岩是一种热水沉积钾长石岩的认识。富钾板岩是白云鄂博矿区的一种重要岩性,与上下岩层呈不规则层状或夹层产出,致密状微晶或隐晶质结构。其中钾长石含量在80%以上,X射线衍射分析表明其2θ(2-01)=21 00,2θ(060)=41 800,2θ(2-04)=50 560,求得三斜度Δ=0 91,有序度δ=0 89,属于典型的低钠、低温、有序最大的微斜长石,微斜长石成分占98%以上。岩石中富含微量元素B、F、Sr、Ba,平均质量分数分别为26×10-6、3386×10-6、119×10-6和1735×10-6,结合X射线衍射分析表明微斜长石中有冰长石成分。稀土元素以轻稀土富集、重稀土亏损、个别出现正铕异常为特征。根据热水流体中钾浓度与温度的相关性及热水沉积、交代和充填物中经常出现钾长石矿物,分析认为白云鄂博矿区出现的富钾板岩是热水沉积钾长石岩,其形成于火山期后的溶液活动阶段。
Krich slate in Baiyun'ebo mine occurs in irregular form or interstratification with condensed microlite or cryptocrystalline structure. The content of Kfeldspar is more than 80%.By analysis of Xray diffraction,the data obtained are as follows:2θ(2-01)=2100, 2θ(060)=41800, 2θ(2-04)=50560,and triclinic degree is 091 and order degree is 089.So,Kfeldspar is typically epithermal microcline with lowerNa and the largest order, making up to 98%. There are high contents of trace elements such incompatible elements as B, F, Sr, and Ba,averaged out 26×10-6,3?386×10-6,119×10-6, and 1?735×10-6,respectively. Combined with the analysis of Xray diffraction, microcline contains somewhat of dulavia.The Krich slate is rich in light REE and poor in heavy REE, and even shows europium abnormal. Based on the correlation between K concentration and temperature, and analysis of the fact that Kfeldspar often appears in the replacement and filling material,it is suggested that Krich slate in Baiyun'ebo is hydrothermal sediment, which formed at the late period of volcanic solution activity.
出处
《现代地质》
CAS
CSCD
2003年第3期281-286,T005,T006,共8页
Geoscience
基金
国家自然科学基金项目(40073013)
国土资源部国际合作与科技司自由探索项目(2000440)。
