| 甘肃北山造山带南缘白石坝一带南岭型花岗岩地球化学特征与锡成矿作用浅析 |
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| 引用本文： | 王晓伟,杨春霞,王启航,王玉玺,高翔.甘肃北山造山带南缘白石坝一带南岭型花岗岩地球化学特征与锡成矿作用浅析[J].矿产与地质,2016(2):157-163. |
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| 作者姓名： | 王晓伟 杨春霞 王启航 王玉玺 高翔 |
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| 作者单位： | 1. 甘肃省地质调查院，甘肃 兰州 730000; 甘肃省地质矿产勘查开发局，甘肃 兰州 730000;2. 甘肃省地矿局第三地质矿产勘查院,甘肃 兰州,730050;3. 甘肃省地质调查院,甘肃 兰州,730000 |
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| 基金项目： | 甘肃国土资源厅石板泉一带1∶50000矿产远景调查项目[甘财建(2010)254]和甘肃省金塔县白石坝锡铁多金属矿普查项目[甘国土资勘发(2012)45号]资助。 |
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| 摘 要： | 白石坝一带花岗岩具高硅低铝、富钾贫钠、非常低Sr(24.9×10~(-6)~82.9×10~(-6))高Yb(2.61×10~(-6)~5.74×10~(-6))的南岭型花岗岩特征,A/CNK介于0.91~0.98之间,σ在1.92~2.22之间。明显富集Rb、Th、K等大离子不相容元素,亏损Ba、Sr、P、Ti等元素,并具有弱Nb亏损,稀土元素分布曲线呈明显的"燕式"型,其形成可能来源于下地壳底部部分熔融与地壳物质发生混合形成的产物,源区深度较浅、水含量低和氧逸度低,处于还原状态下的伸展构造背景,有利于锡矿的萃取和富集,研究其区域构造-岩浆演化,对指导区域矿产预测和评价均具有重要的理论和实际意义。
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| 关 键 词： | 花岗岩 南岭型 地球化学 成矿作用 北山造山带 |
Geochemical characteristics of Nanling type granite in Baishiba area at the south rim of Beishan orogenic belt and the effect of tin mineralization |
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| Abstract: | Granite in Baishiba area has characteristics of Nanling type granite which has high silicon and potas-sium content and low aluminum and sodium content,and a extremely low content of Sr (24.9×10 -6 -82.9 ×10 -6 )and high content of Yb (2.61 ×10 -6 -5.74×10 -6 ).The A/CNK value ranges from 0.91 to 0.98 and σvalue from 1.92 to 2.22.There is an obvious enrichment of large-ion incompatible elements like Rb, Th and K,and a depletion of elements like Ba,Sr,P and Ti and a slight depletion of Nb.The rare earth ele-ment distribtion curve is a typical “swallow-like”pattern.The granite is possibly a product of migmatization of the melted parts at the bottom of the lower crust with the crust materials.The source area has a shallow depth and relatively low water content and low oxygen fugacity.Extensional tectonic setting under the reducing condition is favorable for extraction and enrichment of tin ores.The study of the tetonic-magmatic evolution in the area has important theoretical and practical significance in the regional mineral occurrence prediction and assessment. |
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| Keywords: | granite Nanling type geochemistry mineralization Beishan orogenic belt |
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