海南蓬莱刚玉巨晶中铌(钽)铁矿包裹体及其意义  

TANTALIC COLUMBITE INCLUSIONS IN CORUNDUM MEGACRYSTS IN PENGLAI, HAINAN

作　　者：丘志力[1] 秦社彩[2] 陈小明[3] 

机构地区：[1]中山大学地球科学系,广州510275 [2]中山大学学报,广州510275 [3]南京大学内生金属矿床成矿机制研究国家重点实验室,南京210093

出　　处：《矿物学报》2001年第2期205-208,共4页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目 (批准号 :4960 2 0 2 5 ) ;南京大学内生金属矿床成矿机制国家重点实验室基金项目 (批准号 :0 4980 2 )

摘　　要：铌 (钽 )铁矿是基性岩与超基性岩中极为罕见的矿物。运用电子探针分析了海南蓬莱与碱性玄武岩有密切成生联系的刚玉巨晶中的铌 (钽 )铁矿包裹体的成分 ,确定其晶体化学式为 (Fe0 .72 6Mn0 .168) 0 .894 (Nb1.80 8Ta0 .0 67Ti0 .2 0 8) 2 .0 83 O6。讨论了铌 (钽 )铁矿的形成与刚玉巨晶的关系 ,认为刚玉巨晶的形成可能和岩浆混合或上地幔流体交代作用有关。Tantalic columbites, rare minerals in basic and ultrabasic magmatic rocks, are found as mineral inclusions in corundum megacryst detritals from eluvial deposits of Tertiary alkali basalts in Penglai, Hainan. The chemical compositions of tantalic columbite inclusions in corundum megacrysts are obtained using EPTA. The crystalline chemistry formula of the tantalic columbite is (Fe\-\{0.726\} Mn\-\{0.168\})\-\{0.894\}(Nb\-\{1.808\}Ta\-\{0.067\}Ti\-\{0.208\})\-\{2.083\}O\-6 calculated from its chemical composition. According to the composition and other evidences, it is concluded that the formation of corundum megacrysts may be related to mixing of magmas or alteration of fluids in the upper mantle.

关 键 词：铌铁矿包裹体 刚玉 巨晶 碱性玄武岩 电子探针 上地幔流体 交代作用 晶体化学式 

分 类 号：P578.4[天文地球—矿物学]