| 巴尔哲超大型稀有稀土矿床成矿机制研究 |
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| 引用本文： | 杨武斌,牛贺才,单强,罗勇,于学元,裘愉卓.巴尔哲超大型稀有稀土矿床成矿机制研究[J].岩石学报,2009,25(11):2924-2932. |
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| 作者姓名： | 杨武斌 牛贺才 单强 罗勇 于学元 裘愉卓 |
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| 作者单位： | 1. 中国科学院广州地球化学研究所,广州,510640;中国科学院研究生院,北京,100049
2. 中国科学院广州地球化学研究所,广州,510640 |
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| 基金项目： | 国家自然科学基金，国家重点基础研究发展规划项目 |
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| 摘 要： | 巴尔哲矿床中的矿化和非矿化碱性花岗岩主要造岩矿物均为微斜长石、石英、钠闪石和钠长石,但其相对含量及颗粒大小明显不同,且两类岩石中包裹体的组成特征及锆石的结晶习性也有显著差异.主量元素分析显示,矿化与非矿化碱性花岗岩均以富硅、富碱、贫镁和钙为特征,为较典型的非造山A型花岗岩.尽管矿化碱性花岗岩中K_2O和Na_2O的含量均没有明显的增加,但其Na+K/Al、Na_2O+K_2O/CaO、FeO~*/MgO及K_2O/MgO等岩石化学参数与非矿化碱性花岗岩明显不同.在矿化碱性花岗岩中除了矿化的稀土元素及Nb、Zr强烈富集外,U、Th及Y也明显富集,而Ba、Sr、P、Eu和Ti表现为强烈的亏损.在非矿化碱性花岗岩中除了大离子亲石元素Rb略有富集外,稀土元素、Nb、Zr、U、Th、Ta及Y并无明显富集,虽然Sr、P、Eu和Ti也表现为亏损,但与矿化碱性花岗岩相比其亏损程度明显降低.岩相学、岩石化学及微量元素地球化学特征显示,矿化碱性花岗岩不可能是非矿化碱性花岗岩硅化和钠长石化作用的产物,二者应是同一岩浆体系不同演化阶段熔体固结的产物.K/Rb、Rb/Sr及δEu等地球化学参数显示,矿化碱性花岗岩是高演化A型花岗质熔体固结的产物;而岩石学、包裹体及地球化学特征则显示,这种高演化的A型花岗质熔体已经进入了岩浆一热液过渡阶段.巴尔哲矿床稀有稀土元素的超常富集和成矿与A型花岗岩的高演化过程密切相关.
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| 关 键 词： | 巴尔哲 稀有稀土元素 矿化与非矿化碱性花岗岩 岩浆-热液过渡阶段 成矿作用 |
Ore-forming mechanism of the Baerzhe super-large rare and rare earth elements deposit |
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| YANG WuBin,NIU HeCai,SHAN Qiang,LUO Yong,YU XueYuan,QIU YuZhuo.Ore-forming mechanism of the Baerzhe super-large rare and rare earth elements deposit[J].Acta Petrologica Sinica,2009,25(11):2924-2932. |
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| Authors: | YANG WuBin NIU HeCai SHAN Qiang LUO Yong YU XueYuan QIU YuZhuo |
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| Abstract: | The major rock-forming minerals are same in both barren and mineralized alkaline granites at the Baerzhe deposit,mainly composed of microcline,quartz,riebeckite and albite.However,their relative contents and grain sizes are obviously different,as well as the compositions of fluid inclusions and the crystal habits of zircon also show significant differences in these two types of granites.The data on petrology,petroehemistry and element geochemistry suggest that the mineralized alkaline granite is not formed by means of the silicification and albitization of barren alkaline granite.The data also confirmed that these two types of granites are products of crystallization from a same magrnatie system at different positions belonging different evolutional stages.And the characteristics on petrology,inclusions and geochemistry show that the highly evolved A-type granitic melt has stepped into magmatic-hydrothemal transition stage.The extraordinary enrichment and mineralization of rare and rare earth elements are closely related to the highly evolved A-type granite in the Baerzhe deposit. |
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| Keywords: | Baerzhe Rare and rare earth elements Barren and mineralized(Baerzhe)alkaline granites Magmatic-hydrothemal transition stage Mineralization |
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