夹皮沟金矿区黑云母的化学成分及红外谱学特征

THE CHARACTERISTIC OF THE CHEMICAL COMPOSITION AND INFRARED SPECTRUM OF BIOTITES IN JIAPIGOU GOLD DEPOSITS

从矿区各种不同变质岩相的代表性岩石以及海西期花岗岩中,采集了14个黑云母单矿物样品。化学分析结果证实,随岩石变质程度增高,Al_(IV)^(3+)及钾的含量降低,Mg/(Fe^(2+)+Fe^(3+))增大,(OH)降低。利用μH_2O～μ(K_2O+Na_2O)图解可以相对估计生成岩石的地质环境和区分本区变质岩的原岩类型。用定量法作的红外光谱分析表明,650cm^(-1)吸收频段随含铁系数(f)增高向低频方向偏移,3400cm^(-1)频段与黑云母中(OH)含量有关,随变质程度增高,这个频段的吸光度有所降低。

Fifteen monomineral samples of the biotite were collected from the typical rocks of various metamorphic facies and Hercynian granite in the study area.The result of chemical analysis shows that the content of Al_(1v)^(3+), K, and (OH) decreases and Mg/(Fe^(2+) + Fe^(3+))ratio increases with the intensifying of the metamorphic grade.Using the μH_2O—μ(K_2O+ Na_2O) diagram we can relatively estimate the geological condition where the rocks were formed and distinguish primary types of the rocks.Quantitative analysis of infrared spectrum indicates that 650 cm^(-1) shifted to the lower frequency as ferruginous coefficien increases.When the metamorphic grade intesified, the absorbance of 3400 cm^(-1) frequency related with (OH) content of biotites dicreased somewhat.