青海沙柳河矿区侵入岩地质特征及成矿意义
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摘要
沙柳河矿区大地构造位置属于柴北缘加里东地槽褶皱带东缘,区内印支期侵入岩分布广泛.通过对侵入岩物质成分、岩性特征、岩石化学特征的研究,从侵入岩形成时代、岩石特征及岩石地球化学特征等方面分析了侵入岩与钨锡矿成矿之间的关系.分析认为区内成矿岩体以黑云二长花岗岩为主,属于S型花岗岩,具有酸度大、含碱量不高的特点,属弱碱性—过碱性硅铝过饱和类型花岗岩,其含副矿物种类较多.岩石中Pb、Zn、W、Sn元素含量均高于世界花岗岩平均值的1.5~3.3倍,为钨锡成矿提供了物质来源.利用花岗岩K+Na与Si相关图、SiO_2-(CaO+MgO+FeO)-(Na_2O+K_2O+Al_2O_3)三相图、分异指数直方图等方法对区内的花岗岩进行分析,认为普查区似斑状黑云二长花岗岩(含云英岩化二长花岗岩)在岩性特征、岩石化学、物质成分及形成时间等方面,均表现出与国内外锡钨成矿岩体非常相似之处,属有利的成矿母岩.
The Shaliuhe tungsten-tin orefield in Qinghai Province,tectonically belonging to the eastern margin of the Caledonian synclinorium fold belt in northern Qaidam Basin,is broadly intruded by Indosinian rocks. With discussion on the composition,lithology and petrochemistry of intrusive rocks,this paper analyzes the relationship between the rocks and the W-Sn metallogenesis. The result shows that the ore-forming rock in the orefield is dominated by biotite monzogranite,belonging to S-type of weak alkaline-peralkaline silica-aluminum supersaturated granite,with various kinds of accessory minerals. The Pb,Zn,W and Sn contents in the rock are 1.5-3.3 times higher than the world average values of granite,suggesting that the intrusive rock in the area is the material source for W-Sn mineralization.The granite is analyzed with the approaches of(K+Na)-Si correlation diagram,SiO_2-(CaO+MgO+FeO)-(Na_2O+K_2O+Al_2O_3)phase diagram and differentiation index histogram. It is concluded that the porphyraceous biotite monzogranite in the orefield shows great similarity to the W-Sn ore-forming rocks both in China and abroad in lithology,petrochemistry,composition and forming time,to be a favorable metallogenic parent rock.
The Shaliuhe tungsten-tin orefield in Qinghai Province,tectonically belonging to the eastern margin of the Caledonian synclinorium fold belt in northern Qaidam Basin,is broadly intruded by Indosinian rocks. With discussion on the composition,lithology and petrochemistry of intrusive rocks,this paper analyzes the relationship between the rocks and the W-Sn metallogenesis. The result shows that the ore-forming rock in the orefield is dominated by biotite monzogranite,belonging to S-type of weak alkaline-peralkaline silica-aluminum supersaturated granite,with various kinds of accessory minerals. The Pb,Zn,W and Sn contents in the rock are 1.5-3.3 times higher than the world average values of granite,suggesting that the intrusive rock in the area is the material source for W-Sn mineralization.The granite is analyzed with the approaches of(K+Na)-Si correlation diagram,SiO_2-(CaO+MgO+FeO)-(Na_2O+K_2O+Al_2O_3)phase diagram and differentiation index histogram. It is concluded that the porphyraceous biotite monzogranite in the orefield shows great similarity to the W-Sn ore-forming rocks both in China and abroad in lithology,petrochemistry,composition and forming time,to be a favorable metallogenic parent rock.
引文
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[2]陈正乐,周显强,宋友贵.青海都兰沙柳河南区多金属矿床的控矿构造特征[J].地质力学学报,1997(2):84-91.
[3]张雪亭,杨生德,杨站君,等.1∶1000000青海省大地构造图及其说明书[M].北京:地质出版社,2007:56-64.
[4]徐耀鉴,等编.岩石学教程[M].北京:地质出版社,2007:98-103.
[5]汪雄武,王晓地.花岗岩成矿的几个判别标志[J].岩石矿物学杂志,2002(2):119-130.
[6]汪雄武,王晓地.花岗岩成矿的地球化学判别标志[J].华南地质与矿产,2001(4):36-44.
[7]马永铨,姜洪成.青海省沙柳河南区有色金属矿成矿物质来源及矿床成矿模式探讨[J].青海地质,1994(1):26-39.
[8]姜洪成,马永铨.青海省沙柳河南区有色金属矿床的成矿物理化学条件研究[J].青海地质,1993(2):17-31.
[9]孙少财,王伟.青海省察汗乌苏-乌龙滩地区成矿远景评价[J].化工矿产地质,2013(3):162-168,192.
[10]华仁民.关于花岗岩成因分类与花岗岩成矿作用若干基本问题的思考——与张旗先生等商榷[J].矿床地质,2011(1):163-170.
[11]秦长兴.识别华南燕山期含锡花岗岩的岩石化学方法及其在新路矿区的应用[J].地球科学,1987(4):435-440.
[12]朱金初,徐士进.华南含锡钨花岗岩的稀土元素地球化学特征和岩石成因[J].矿床地质,1989(3):21-31.
[13]周显强,宋友贵,邓军,等.青海都兰地区矿田构造与控矿特征[M].北京:地质出版社,1996.
[14]丁正江,孙丰月,李碧乐,等.青海省苦海汞(金)矿床地质特征及找矿前景分析[J].地质与勘探,2010,46(2):198-206.