金伯利岩中新发现的两种Zr-Ti、REE-Ti氧化物矿物──上地幔含大阳离子Cr、Ti、Fe氧化物矿物研究之四  

NEW KIND OF Zr-Ti, REE-Ti OXIDE MINERAL FROM KIMBERLITE──STUDY OF OXIDE MINERALS BEARING BIG CATIONS Cr,Ti,Fe FROM UPPER MANTLE, PART IV

作　　者：陆琦[1] 周湖云[1] 刘惠芳[1] 雷新荣[1] 

机构地区：[1]中国地质大学,武汉430074

出　　处：《矿物学报》1997年第3期270-275,共6页Acta Mineralogica Sinica

基　　金：国家自然科学基金!49272092;地质矿产部壳幔开放实验室联合资助

摘　　要：在研究沂蒙矿、蒙山矿等地幔矿物时，新发现了两种Zr－Ti、REE－Ti氧化物矿物。Zr－Ti氧化物新相6个样品点的探针成分分析（wt％）：TIO227.756～46.811，ZrO231.724～58.092，TFeo2.75～5．82，CrO31．728～4．765，Nb2O51．353～4．357，Ta2O50．155～2.814，SiO20．894～13．749，主次元素的成分变化幅度均较大，但以氧为4计算的阳离子总数均为2，因此分子式可简写为（Ti，Zr，Si，Fe）2O4或（Ti，Zr）2O4，与人工化合物ZrTiO4相似。REE－Ti氧化物矿物新相的成分也较复杂，主要元素为REE（Ce，Nd，La，Sm，Pr…）及Ti，次要元素有Nb，根据五个样点的探针分析结果，简化的分子式（Ce…）2（Ti…）3O9，与人工化合物Ce2Ti3O8.7类似，属等轴晶系。两个新矿物相均产于蒙山矿中的微裂隙和熔融交代海绵边中，呈斑点状、蠕虫状、微脉状，组成元素复杂，不同颗粒分析点成分有差异，且在同一微脉中成分也有变化，反映了这两种新矿物相是非平衡的交代一结晶产物。从矿物的产出关系和成分的特征来看，它们的形成与地幔流体交代作用有关。When researching mantle minerals of yimenlite and mathiasite, we discovered two kindof new Zr-Ti. REE-Ti oxide minerals. The chemical compositions of 6 points of the new Zr-Ti ox-ide mineral were: TiO2 27. 756～46. 811 (wt % ): ZrO2 31. 724～58. O92; TFe 2. 75～5. 82 ; Cr2O31. 728～4. 765; Nb2O5 1.353～4. 357; Ta2O5 0. 155～2．814; SiO2 0. 894～13. 749, and their vari-ations were relatively high, but when calculated according to 4 oxygen, the total number of cationswas 2, so the chemical formula simplified to: (Ti, Zr, Si, Fe ),O, 0r (Ti, Zr),O', that is similar t6synthesized compound ZrTiO'. The chernical compositions of newly found REE-Ti oxide mineralwere also complex, and the rnain eIen1ents were REE (Ce, Nd, La, Sm, Pr… ) and Ti, minor ele-ments Nb. According to electron probe analyzing results of 5 points， its simplified formula was:(Ce… )2(Ti… )3O9, that is similar to synthesized compound Ce2Ti3O8. 7 , and that belongs to cubicsystem.These two new minerals were located in micro-fracture and melting alternated sponge bound-ary of Mathiasite, and its shapes werc spots-like, worm-like, and micro-veins. Their compositionswere very complex, and verified according to the analyzing points and the grains. That demon-strated that this two kind of minerals was crystallized results of non-equilibrium. From their loca-tion and compositional characteristic, the forming of this two new minerals is related to the liquidalternation from mantle.

关 键 词：金伯利岩 氧化物矿物 锆 钛 铬 铁 

分 类 号：P588.125[天文地球—岩石学]