四川攀枝花钒钛磁铁矿成矿元素富集状态及其成矿意义

发布时间：2018-03-19 10:34

本文选题：钒钛磁铁矿矿床　切入点：成矿元素赋存状态　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：攀枝花钒钛磁铁矿矿床位于康滇地轴中段,隶属于峨眉山大火成岩省内带,富含的矿产资源丰富多样,其中钒钛磁铁矿资源储量巨大。攀枝花岩体可划分为上部辉长岩体和底部橄榄岩体两个部分,其中含矿岩体根据岩(矿)体的韵律特征,可划分为底部的暗色辉长岩相带,中部的层状辉长岩相带,上部浅色辉长岩相带和边缘岩相带4个岩相带。其中,下部岩相带中可划分为5个韵律旋回层,中部岩相带6个韵律旋回层,上部无明显的韵律旋回层。每一韵律旋回层中,铁钛氧化物的含量逐渐由下而上逐渐减少,硅酸盐矿物含量逐渐增加。攀枝花辉长岩主量元素中SiO2含量介于28.33%-46.67%之间;Na20+K2O含量介于0.71%-3.63%之间;Ti02含量介于 2.74%-8.54%之间;A/NCK 比值介于 0.74-1.38 之间,属于过铝质-低钾拉斑质碱性岩系列。相伴生的峨眉山玄武岩主量元素中SiO2含量介于45.36%-59.57%之间;Na20+K20 含量介于 1.24%-6.43%之间;Ti02 含量介于 2.21%-5.87%之间;A/NCK比值介于0.82-1.47之间,属于过铝质-钙碱性-亚碱性岩系列。攀枝花含矿辉长岩属于轻稀土富集型,轻重稀土分馏一般,除了下部岩相带中辉长岩具明显的Eu正异常外,均显示不明显的EU正异常;相伴生的峨眉山玄武岩属于轻稀土富集型,轻重稀土分馏较为明显,Eu正异常不明显。攀枝花含矿辉长岩的微量元素含量普遍较低,且亏损Rb、Th、U、La、Ce等不相容元素,其中,含矿辉长岩比浅色和细粒不含或含少量矿辉长岩La、Ce、Nd、Sm和Y、Yb、Lu等元素也普遍偏低。据攀枝花辉长岩高Ti特征,可能其在源区上与峨眉山高钛玄武岩类似,源区物质为地幔柱物质与岩石圈地幔高程度部分熔融的混溶物质;而相伴生的峨眉山玄武岩源区为岩石圈地幔低程度部分熔融物质。且两者均受到一定程度的地壳物质的混染作用,其中玄武岩比辉长岩混染作用更加强烈。矿物微区电子探针分析数据显示,V、Fe、Ti等成矿元素赋存状态具有明显的规律性:1)不同韵律层中富铁的层位和贫铁层位中,橄榄石FeO含量具有富铁层位低、贫铁层位高的特点;MgO含量及其相应的Fo牌号具有与FeO含量变化相反的韵律式变化。2)斜长石在每个韵律层CaO和A1203自下而上逐渐减少,而Na2O含量则逐渐增加,反映了斜长石An牌号具有自上而下逐渐增加趋势。3)矿石矿物中钛铁矿,在块状矿石中MgO、Ti02含量最高,FeO、Fe203含量最低,而贫铁层位中这些氧化物含量却与之相反,而富铁层位中这些氧化物含量基本变化不大。磁铁矿中MgO和TiO2含量具有和钛铁矿一致的变化规律,并且钛铁矿这两种氧化物的含量与磁铁矿中的含量基本呈正相关,却与Al2O3呈反相关。上述工作查明了成矿元素在不同岩相带,不同矿物中的变化规律,揭示了攀枝花含矿岩体可能是经过多期次富含铁钛岩浆补充的复合岩体,每次新岩浆的加入都伴随着氧逸度是递进式锐减。成矿元素的富集不仅受含矿岩体的母岩浆的成分的影响,还受岩浆的性质、氧逸度、分异程度、挥发组分的制约。含矿岩体的多期次脉动叠加、岩浆深部的结晶分异与重力分异是底部成矿最重要的控制因素。与地幔柱作用有成因联系的多期次岩浆的侵入与喷发,不仅有利于V-Fe-Ti等成矿物质富集及沉淀,而且在区域上也形成了与之相伴生的铜镍硫化物矿床,构成比较完整的具有成因联系的岩浆成矿系列。根据不同矿物相中赋存的成矿元素具有的明显差异性,可为选矿工艺的制定提供技术支撑。
[Abstract]:Panzhihua V-Ti-magnetite deposit is located in the middle section of KANGTIEN axis, belonging to the Mount Emei fire igneous province, rich in mineral resources is abundant, the huge reserves of vanadium titanium magnetite resource. Panzhihua rock can be divided into two parts the upper gabbro and peridotite bottom, the ore rock rock (ore) according to the prosodic features of body. Can be divided into dark glow with long at the bottom of the lithofacies, layered gabbro central facies, upper gabbro facies and light edge facies of 4 lithofacies. The lower facies can be divided into 5 rhythm layers, 6 rhythm zone central facies, upper layer without rhythm obviously. Each layer of rhythm, the content of Fe Ti oxides gradually decreased from bottom to top, silicate mineral content increased gradually. The content of SiO2 between 28.33%-46.67% of Panzhihua gabbro majorelements in Na20+K2O; Between the content between 0.71%-3.63%; the content of Ti02 ranged between 2.74%-8.54%; the ratio of A/NCK between 0.74-1.38, which belongs to peraluminous and low potassium tholeiitic to alkalic series. Between 45.36%-59.57% SiO2 in Mount Emei basalt main elements associated; the content of Na20+K20 ranged between 1.24%-6.43%; the content of Ti02 ranged between 2.21%-5.87%; the ratio of A/NCK between 0.82-1.47, which belongs to peraluminous calc alkaline and sub alkaline series. Panzhihua ore gabbro belongs to LREE enrichment, REE fractionation, in addition to lower facies with gabbro obvious positive Eu anomaly, showed no obvious positive EU anomaly; associated Mount Emei basalts belong to the LREE enrichment type, REE fractionation obviously, Eu positive anomaly is not obvious. The content of trace elements in Panzhihua ore gabbro is generally low, and the loss of Rb, Th, U, La, Ce and other incompatible Among them, the ore elements of gabbro than light and fine ore containing no or little Ce, Nd, gabbro, La, Sm and Y, Yb, Lu and other elements are generally low. According to the characteristics of Panzhihua gabbro high Ti, which may be in the source region and the Mount Emei high titanium Xuan Wuyan is similar to that of source material for miscible substances the high degree of partial melting of mantle plume and lithospheric mantle; and the associated Mount Emei Xuan Wuyan lithospheric mantle source region was low degree partial melting material. And both of them are contaminated by crustal material to a certain extent, the Xuan Wuyan gabbro contamination more strongly. Mineral electron microprobe analysis data showed that V Fe, Ti, the occurrence state of the metallogenic elements have obvious regularity: 1) different layers of rhythmite iron rich and poor iron layer, FeO content of olivine with iron rich layer is low, poor iron layer high; the MgO content and the corresponding grade of Fo With the rhythmic change with the change of FeO content in.2) plagioclase gradually decreased in layers CaO and A1203 each rhythm from the bottom up, while Na2O content was increased gradually, reflecting the An number of plagioclase has increased gradually from top to bottom).3 ilmenite ore minerals, massive ore in MgO, the highest content of Ti02, FeO, Fe203 content the lowest, while poor iron oxide content in these layers was the opposite, and the iron rich layers of these basic oxide content changes little. With MgO and TiO2 content in magnetite and ilmenite rules consistent changes, and the basic content of titanium iron ore and magnetite content was two in the oxide, but inversely associated with the Al2O3. The work to identify the ore-forming elements in different facies, the change regularity of different minerals in Panzhihua, reveals the ore bearing rock is possible through many times of magma rich in Fe Ti added Composite rock, with each new magma are accompanied by oxygen fugacity is progressive collapse. Enrichment of ore-forming elements not only by ore rock magma composition effects, but also by the nature of the magma, oxygen fugacity, degree of differentiation, restricting the volatile components. Orerock multi-stage pulse dynamic superposition and gravity crystallization deep magma differentiation is the most important control factors of mineralization. The bottom has eruption and intrusion related many times of magma and mantle plume, not only conducive to the enrichment and precipitation of minerals such as V-Fe-Ti, and in the region also formed with copper nickel sulfide deposit, a relatively complete associated with genesis of magma metallogenic series. According to the difference of ore-forming elements in different mineral phases in the feature for the beneficiation process formulated to provide technical support.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.2

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