川西甲基卡伟晶岩型矿床中含硅酸盐子矿物包裹体的发现及其意义

伟晶岩对研究岩浆向热液的演化过程具有重要的研究意义。近年来，花岗岩浆的不混溶作用日益得到重视，被认为是伟晶岩形成的重要控制因素。川西甲基卡伟晶岩型矿床是中国最大的固体锂矿床。本人在甲基卡矿床中发现了大量富含挥发份的含硅酸盐子矿物的包裹体，这些包裹体不同于阿尔泰可可托海伟晶岩矿床和加拿大Tanco伟晶岩矿床中的熔体-流体包裹体，而同不混溶成因的水盐熔体组成相近。其他地质特征也表明，甲基卡矿床发生了花岗岩浆的不混溶作用。因此，可判断出，甲基卡矿床中的含硅酸盐子矿物包裹体是花岗岩浆不混溶作用的产物，为甲基卡矿床的花岗岩浆不混溶成因提供了新的佐证。     

甲基卡花岗岩及伟晶岩脉岩石学特征

通过甲基卡花岗岩体及伟晶岩脉实测剖面,研究其岩石学特征,分析其其构造背景及物质来源。岩体主要由二长花岗岩和正长花岗岩组成,以中-细粒结构为主,可见白云母、黑云母等矿物。组成伟晶岩脉的长石、石英等矿物普遍较粗大,岩脉中可见锂辉石矿物。由于岩石中普遍可见富铝矿物白云母,因此推测岩体可能来源于地壳物质。花岗质岩浆形成后发生了液态不混溶作用,分离出伟晶岩熔体并交代围岩使稀有金属元素富集成矿。     

川西甲基卡308号脉的矿物学特征及其岩浆- 热液演化示踪

甲基卡稀有金属矿床是亚洲规模最大的伟晶岩型锂矿床，308号脉为其中出露面积最大的伟晶岩脉。308号脉具有完善的分带性:细粒白云母- 钠长石- 石英带（Ⅰ）、中粗粒钠长石- 石英- 微斜长石带（Ⅱ）、中粒电气石- 钠长石- 石英带（Ⅲ）、中粗粒锂辉石- 钠长石- 石英带（Ⅳ）和中细粒锂辉石- 钠长石- 石英带（Ⅴ），并且富含稀有金属矿物（如锂辉石、绿柱石、锡石和铌钽氧化物），因此是系统研究伟晶岩演化历史和成岩成矿机制的理想实验对象。308号脉的矿物学研究较为薄弱，其岩浆- 热液演化过程及该过程中熔- 流体性质的变化规律，以及稀有金属的富集过程和影响因素尚不清楚。本文选取该脉各结构带中的贯通性矿物云母、磷灰石，以及稀有金属矿物锂辉石和特征性矿物电气石，通过详细的电子探针工作，分析它们的产状、结构特征、化学组成及其变化，结果表明:① 308号脉边部Ⅰ带（高温结晶）中电气石的出现（~5%）反映伟晶岩初始熔体具有富B的特征（>2%）；锂辉石在Ⅳ和Ⅴ带内的大量结晶说明初始熔体可能具有富Li的性质；主要含氟矿物电气石、磷灰石和云母类在岩石中的含量均较低，并且原生磷灰石具有相对偏低的F浓度（<3%），仅能形成于富F环境中的锂云母矿物也十分稀少，这些特征均表明308号脉初始熔体很可能具有较低的F含量；② 伟晶岩体系演化至Ⅴ带时发生流体出溶现象，自此进入岩浆- 热液过渡阶段，出溶流体可能具有富Cs和贫F的性质；③ 原生白云母和电气石化学成分的规律性变化说明308号脉的演化过程很可能不存在外来流体的加入；④ 308号伟晶岩的成岩和锂成矿过程主要受分异结晶作用支配，有限的出溶流体规模和伟晶岩分异演化程度（仅演化至岩浆- 热液过渡阶段，未充分进入热液阶段）对锂辉石的结晶和保存都起到了重要作用。     

云南哀牢山和新疆可可托海伟晶岩矿物中熔融包裹体电子探针研究

运用电子探针测定了云南哀牢山伟晶岩和新疆可可 托海伟晶岩矿物中熔融包裹体及流体-熔融包裹体子矿物成分。据73个包裹体中120个测 点分 析结果,鉴定出锌尖晶石、刚玉、磷灰石、磁铁矿、白云母、黑云母、钾长石、钠长石、绿 柱石和石英等10种 子矿物,并确定矿物组合27个。其中锌尖晶石、刚玉在两地区伟晶岩熔融包裹体中属首次发 现,磷灰石成分属首次测定。两地伟晶岩矿物的熔融及流体-熔融包裹体中子 矿 物成分及矿物组合各异,包裹体中子矿物与主矿物的化学成分存在一定演化规律,可作为了 解伟晶岩浆结晶分异作用、元素演化规律的依据。研究表明,伟晶岩存在局部岩浆分异作 用,岩浆具不混溶性及非均匀性。此成果对了解伟晶岩物质成分、形成机制及成因研究具重 要意义。对岩浆岩、地幔岩及陨石研究也有一定启迪。     

新疆阿尔泰可可托海3号伟晶岩脉岩浆—热液演化和成因

新疆阿尔泰可可托海3号伟晶岩脉,由一陡倾斜的巨大岩钟和缓倾斜的板状体联合组成,总 体形态似一实心草帽。其空间分带十分明显,自外向内可依次划分出如下九个共生－结 构带 ：Ⅰ 文象、变文象伟晶岩带;Ⅱ 糖粒状钠长石带;Ⅲ 块状微斜长石带;Ⅳ 白云母-石英 带;Ⅴ 叶钠长石-锂辉石带;Ⅵ 石英-锂辉石（-叶钠长石）带;Ⅶ 白云母-薄片状钠长石 带;Ⅷ 锂云母-薄片状钠长石带;Ⅸ 石英和微斜长石核。根据伟晶岩各共生－结构带的时 空关系、矿物的多世代性和矿物中的包裹体等特征,从岩浆－热液演化的角度,探讨了伟 晶岩的成因问题,认为：Ⅰ、Ⅲ带和部分Ⅱ、Ⅳ带主要是富水但水不饱和的伟晶岩浆 直接结晶的产物;Ⅴ、Ⅵ、Ⅶ带是在晶体相、熔体相和流体相三相并存的条件下,即岩浆— 热液过渡阶段结晶形成的;Ⅸ带是在热液早阶段从高温富硅酸盐溶质的超临界流体中结晶出 来 的;Ⅷ带和部分Ⅱ、Ⅳ带则是热液交代的产物。但交代流体不是从深部外来,而是从伟 晶岩浆体系本身在分异演化过程中发生液相分离的结果。     

富氟花岗岩浆液态不混溶作用及其成岩成矿效应

除了结晶分异模式外,富氟花岗岩浆液态不混溶作用也是伟晶岩成岩成矿的重要机制。熔体包裹体和实验研究表明,富氟花岗岩浆的液态不混溶会形成富挥发份的贫硅熔体和与其共轭的富硅酸盐熔体。花岗岩中的异离体型伟晶岩和贯入状脉型伟晶岩,挥发份、助熔剂等元素和同位素组成在不混溶相间的突变性是该类不混溶作用的主要标志。富氟花岗岩浆不混溶作用不但可以解释伟晶岩的特征性矿物分带,对传统的伟晶岩成岩理论提出了挑战;还对稀有金属有高度富集作用,这主要归功于F、B、P等挥发份对稀有金属元素的亲和力。然而,目前该类不混溶作用成矿效应的研究还比较薄弱,这主要要归因于没有理想的地质对象。甲基卡矿床是亚洲最大的固体锂矿床,初步研究表明该矿床发生了富氟花岗岩浆液态不混溶作用,是研究氟花岗岩浆液态不混溶过程中稀有金属的分配、迁移、富集规律和机制的理想对象。     

巴尔哲超大型稀有稀土矿床富晶体的流体包裹体初步研究

巴尔哲矿床是一个超大型稀有稀土多金属矿床,它受巴尔哲碱性花岗岩体（株）控制,稀有稀土矿体分布在巴尔哲岩体上部的钠长石碱性花岗岩中。本文在钠长石碱性花岗岩的石英中发现了大量的富晶体的流体包裹体,并对其进行了初步的激光拉曼光谱和显微测温研究。与一般含盐类晶体矿物的三相流体包裹体不同,巴尔哲富晶体的流体包裹体的晶体不是盐类矿物,而是长石、云母等硅酸盐矿物;同时,该类包裹体内还广泛分布着稀土碳酸盐矿物。富晶体的流体包裹体的发现从微观角度揭示了巴尔哲含矿钠长石碱性花岗岩的形成与岩浆-热液过渡阶段有直接的成因联系,并为阐述巴尔哲岩体稀土元素及氧同位素的地球化学特征提供了新思路。稀土碳酸盐矿物在富晶体的流体包裹体中广泛地分布则充分说明。巴尔哲碱性花岗岩演化到岩浆-热液过渡阶段体系内的稀土元素已经达到足以形成独立稀土矿物的富集程度,其稀土元素矿化受岩浆-热液过渡阶段的制约。     

喜马拉雅东段库曲岩体锂、铍和铌钽稀有金属矿物研究及指示意义

稀有金属矿物记录了花岗伟晶岩成岩成矿的重要信息。喜马拉雅是全球著名的淡色花岗岩带,库曲岩体位于喜马拉雅东段的特提斯喜马拉雅岩系中。本文调查了库曲岩体的二云母花岗岩、白云母花岗岩、电气石花岗岩和花岗伟晶岩,其中,花岗伟晶岩涉及花岗岩的伟晶岩相和独立伟晶岩脉。库曲岩体产出的稀有金属矿物包括锂辉石、锂绿泥石、绿柱石、铌铁矿-钽铁矿、钇铀钽烧绿石和细晶石,它们主要赋存于似文象伟晶岩、石英-钠长石-白云母伟晶岩、块体长石-钠质细晶岩、块体长石-电气石钠质细晶岩、锂辉石-块体长石-细晶岩、白云母花岗岩的伟晶岩相以及电气石花岗岩内。显微镜观察、电子探针和LA-ICP-MS测试结果显示锂辉石具有四种产状,包括粗粒锂辉石自形-半自形晶、细粒锂辉石-石英镶嵌晶、中细粒锂辉石-钾长石-钠长石-云母镶嵌晶以及发育锂绿泥石的粗粒锂辉石,揭示了其形成时复杂的熔流体动荡结晶环境。绿柱石背散射电子图像（BSE）下呈均一结构和不均一结构（蚀变边、不规则分带和补丁分带）,元素替代机制包括通道-八面体替代、通道-四面体替代以及通道中碱金属阳离子间的置换。铌铁矿族矿物包括原生、蚀变边和不规则分带结构,部分被钇铀钽烧绿石和细晶石交代。与原生铌铁矿相比,蚀变边和不规则分带铌铁矿族矿物总体上富钽贫锰,显示了结晶分异、过冷却引起的过饱和以及流体作用。根据稀有金属矿物揭示的成因信息,独立伟晶岩脉（似文象伟晶岩）、白云母花岗岩的伟晶岩相和电气石花岗岩在岩浆分异程度、经历的演化过程、以及流体活动方面存在差异,很可能是不同期次岩浆活动的产物。库曲岩体绿柱石的Rb和Zn含量、以及铌铁矿族矿物的Sc₂O₃、SiO₂和PbO含量,与已有指示标志存在相关性,作为潜在指示标志仍需开展更多的研究工作。综合含锂辉石伟晶岩的产出、岩浆分异演化程度、多期花岗质岩浆活动、复杂的流体作用以及所属锂丰度高值区等因素,库曲岩体是喜马拉雅东段找锂的有利地段。     

阿尔泰伟晶岩中流体熔融包裹体成分的研究

对阿尔泰可可托海、柯鲁木特和库威伟晶岩锂辉石及绿柱石中单个流体熔融包裹体各相成分，借助激光拉曼探针进行分析，鉴定出固体相为不同硅酸盐子晶矿物，定量给出了流体相成分。根据子晶矿物和流体相成分估算了整个流体熔融包裹体的成分，并据此进一步讨论了熔体中流体的溶解度问题。流体熔融包裹体成分研究表明熔体中流体已达饱和或过饱和，流体相与熔体相发生分离，相应残余伟晶岩浆体系进入晶体＋熔体＋流体三相共存的岩浆－热液     

川西扎乌龙花岗伟晶岩型锂矿床成矿作用过程——来自流体包裹体与同位素的证据

川西扎乌龙花岗伟晶岩型锂矿床位于甘孜-松潘造山带内,为大型锂矿床.前人基于对扎乌龙系统的流体包裹体研究,认为扎乌龙锂矿形成于500～580℃,压力350 MPa的环境.然而,对于扎乌龙成矿流体的来源及其何种流体挥发分对成矿起主导作用,仍缺乏有效制约.锂辉石型伟晶岩脉是扎乌龙锂矿最富集的类型,脉体内部分带性良好,可划分为4个带:石英-白云母带、斜长石带、钠长石-锂辉石带和石英-锂辉石带.根据地质现象和流体包裹体的岩相学观察,扎乌龙锂辉石型伟晶岩脉可划分为伟晶岩阶段和热液阶段2个主要阶段,锂矿化集中于伟晶岩阶段.文章对扎乌龙成矿流体的来源及成分开展了研究,即对锂辉石型伟晶岩各阶段的流体包裹体进行了激光拉曼光谱、群体包裹体和氢、氧、碳同位素分析.流体包裹体成分揭示,成矿流体由伟晶岩阶段的高温(500～580℃)、低盐度(w(NaCleq)0.8％～8.5％)、富挥发分(Li、P、B等)、弱碱性的硅酸盐水体系,向晚期中高温(300～400℃)、低盐度(w(NaCleq)4.4％～9.6％)、富CO2、弱酸性的盐水体系热液演化.氢、氧同位素组成表明早期成矿流体以岩浆水为主,晚期无明显的大气降水加入.碳同位素分析结果表明,二氧化碳主要来源于岩浆出溶.结合已有的研究成果,笔者认为相对封闭的成矿环境导致挥发组分的大量聚集和弱碱性环境,是扎乌龙锂矿富集与沉淀的主要控制因素.晚期贫F、富Cl的弱酸性热液流体有利于锂辉石的保存.     

The Durulgui rare-metal granite‒pegmatite system in the eastern Transbaikal region: Petrological and geochronological aspects

The Durulgui granite?pegmatite system unites the Dedova Gora granite massif and pegmatite field with the Chalotskoe beryl deposit. New geochronological data on micas from porphyric biotite granites, fine-grained biotite granites, two-mica granites, and Be-bearing pegmatites are discussed. The plateau age of 128.5(±1.5)–131.2(±1.5) should be considered as indicating the formation time of the granite?pegmatite system as a whole. The age of the system implies the possibility of its formation owing to several magmatic pulses. This assumption concerns porphyric and fine-grained biotite granites and two-mica and muscovite granites, the contact between which is locally sharp. At the same time, the succession “two-mica granites → muscovite granites → granite?pegmatites → microcline pegmatites → microcline?albite pegmatites → albite pegmatites” demonstrates gradual facies transitions between rocks, which indicates their emplacement during a single magmatic pulse.     

云南哀牢山和新疆可可托海伟晶岩矿物中熔融包裹体电子探针研究

运用电子探针测定了云南哀牢山伟晶岩和新疆可可 托海伟晶岩矿物中熔融包裹体及流体-熔融包裹体子矿物成分。据73个包裹体中120个测 点分 析结果,鉴定出锌尖晶石、刚玉、磷灰石、磁铁矿、白云母、黑云母、钾长石、钠长石、绿 柱石和石英等10种 子矿物,并确定矿物组合27个。其中锌尖晶石、刚玉在两地区伟晶岩熔融包裹体中属首次发 现,磷灰石成分属首次测定。两地伟晶岩矿物的熔融及流体-熔融包裹体中子 矿 物成分及矿物组合各异,包裹体中子矿物与主矿物的化学成分存在一定演化规律,可作为了 解伟晶岩浆结晶分异作用、元素演化规律的依据。研究表明,伟晶岩存在局部岩浆分异作 用,岩浆具不混溶性及非均匀性。此成果对了解伟晶岩物质成分、形成机制及成因研究具重 要意义。对岩浆岩、地幔岩及陨石研究也有一定启迪。     

川西甲基卡花岗伟晶岩的锂铍成矿作用过程——来自308号脉流体包裹体的约束

甲基卡位于松潘-甘孜造山带内,为特大型花岗伟晶岩型锂-铍矿床.前人以锂辉石中发育的富子晶包裹体为研究对象,着重剖析了甲基卡锂成矿的物理化学条件.然而,就伟晶岩熔(流)体的演化过程,特别是稀有金属成矿的富集机制和物理化学条件,仍缺乏有效制约.308号脉作为甲基卡出露最大的钠长石型锂-铍伟晶岩脉,具有良好的内部分带,较完整...     

Geology,Fluid Inclusion Characteristics and H–O–C Isotopes of Large Lijiagou Pegmatite Spodumene Deposit in Songpan–Garze Fold Belt,Eastern Tibet: Implications for ore Genesis

The large, newly discovered Lijiagou pegmatite spodumene deposit, is located southeast of the Ke'eryin pegmatite ore field, in the central Songpan–Garze Fold Belt (SGFB), Eastern Tibet. The Lijiagou albite spodumene pegmatites are unzoned, granite‐pegmatites of the subtype LCT (Lithium, Cesium, and Tantalum) and consist of medium‐ to coarse‐grained spodumene, lepidolite, microcline, albite, quartz, muscovite, and accessory amounts of beryl, cassiterite, columbite–tantalite and zircon. Secondary fluid inclusions in quartz and spodumene include two‐phase aqueous inclusions (V + L), mono‐phase vapor inclusions (V); three‐phase CO₂‐rich CO₂–H₂O inclusions (CO₂ + V + L) and less abundant liquid inclusions (L). The homogenization temperature of the fluid inclusions are low (257.3 to 204.3°C in early stage, 250.3 to 199.6°C in middle stage, 218.7 to 200.6°C in late stage). Fluid inclusions were formed during the long cooling period from the temperature of the pegmatite emplacement. Liquid–vapor–gas boiling was extensive during the middle and late stages. The salinity of the corresponding stages are 15.4 to 13.0 wt.% NaCl equiv., 12.5 to 9.1 wt.% NaCl equiv. and 9.8 to 7.8 wt.% NaCl equiv., respectively. δ¹⁸O values of fluid are 7.2 to 5.2‰, 5.6 to 3.9‰ and 2.7 to −0.2‰ from early to late stages; and δD range from −75.1 to −76.8‰, −59.0 to −73.5‰ and −61.6 to −85.5‰ respectively. The δ¹³C of CO₂ values are −5.6 to −6.6‰, −8.5 to −19.9‰, −11.8 to −18.7‰ from early to late stages, suggesting that CO₂ in the fluids were probably sourced from a magmatic system, possibly with some mixing of CO₂ dissolved in groundwater. δD and δ¹⁸O values of fluid indicate that the fluids were originally magmatic water and mixed with some meteoric water in late stage. The magma evolution sequence in the Ke'eryin orefield, from the central two‐mica granite through the Lijiagou deposit out to the distal pegmatites, with the ages gradually decreasing, indicates that the Ke'eryin complex rocks are the product of multistage magmatic activity. The large Lijiagou spodumene deposit is a typical magmatic, fractional crystallization related pegmatite deposit.     

The Ore-forming Mechanism of the Jiajika Pegmatite-Type Rare Metal Deposit in Western Sichuan Province:Evidence from Isotope Dating

Granitic pegmatites are commonly thought to form by fractional crystallization or by liquid immiscibility of granitic magma;however,these proposals are based mainly on analyses of fluid and melt inclusions.Here,we use the Jiajika pegmatite deposit,the largest spodumene deposit in Asia,as a case study to investigate ore forming processes using isotope dating.Dating of a single granite sample from the Jiajika deposit using multiple methods gave a zircon U-Pb SHRIMP age of 208.4±3.9 Ma, an ⁴⁰Ar/³⁹Ar age for muscovite of 182.9±1.7 Ma,and an ⁴⁰Ar/³⁹Ar age for biotite of 169.9±1.6 Ma. Based on these dating results and the ⁴⁰Ar/³⁹Ar age of muscovite from the Jiajika pegmatite,a temperature-time cooling track for the Jiajika granite was constructed using closure temperatures of the different isotope systems.This track indicates that the granite cooled over～40 m.y.,with segregation of the pegmatite fluid from the granitic magma at a temperature of～700℃.This result suggests that the Jiajika pegmatite formed not by fractional crystallization,but by segregation of an immiscible liquid from the granitic magma.When compared with fractional crystallization,the relatively early timing of segregation of an immiscible liquid from a granitic magma can prevent the precipitation of ore-forming elements during crystallization,and suggests that liquid immiscibility could be an important ore-forming process for rare metal pegmatities.We also conclude that isotope dating is a method that can potentially be used to determine the dominant ore-forming processes that occurred during the formation of granite-related ore deposits,and suggest that this method can be employed to determine the formation history of the W-Sn ore deposits found elsewhere within the Nanling Metallogenic Belt.     

云南麻栗坡祖母绿的矿物包裹体特征研究

采用偏光显微镜薄片观察、电子探针及背散射图像、阴极发光等方法,分别对伟晶岩矿脉和顺层剪切带矿脉两种产出状态的云南麻栗坡祖母绿进行了系统的包裹体特征研究。结果表明,云南麻栗坡祖母绿具有产地特征的包裹体有黑色镁电气石、含钒的白云母、具有环带的钾长石、毒砂、镁质黑云母、白钨矿包裹体。伟晶岩脉和顺层剪切带中的祖母绿均含有钾长石、钠长石、电气石、萤石、祖母绿(绿柱石)、黑云母、榍石、磷灰石、黄铁矿、绿泥石、绿帘石包裹体。白云母、方解石、石英、锆石、毒砂、闪锌矿、方铅矿、透辉石仅出现在伟晶岩脉中的祖母绿包裹体中;而白钨矿仅出现在顺层剪切带中的祖母绿包裹体中。对云南不同产状祖母绿矿物包裹体的研究不仅对祖母绿的产地鉴定具有宝石学意义,也对揭示云南麻栗坡祖母绿的成因类型具有重要意义。     

川西甲基卡308号伟晶岩脉年代学和地球化学特征及其地质意义

甲基卡稀有金属矿床是我国目前规模最大的伟晶岩型稀有金属矿床,308号伟晶岩脉为其中出露面积最大的伟晶岩脉,由于勘查及研究程度较低,其形成时代及成矿机制尚不明确.通过LA-MC-ICP-MS锡石U-Pb测年,首次获得产于308号伟晶岩脉中间带含锂辉石伟晶岩的年龄为210.9±4.6 Ma,表明其形成于印支晚期,为印支旋回强烈造山运动之后相对稳定阶段的产物.元素地球化学特征表明,308号伟晶岩脉中边缘带无矿细晶岩与矿床内二云母花岗岩具有相似的过铝质S型花岗岩特征,二者具有同源性,并认为其成矿机制为:花岗质岩浆在中浅成、偏还原的环境上升侵位,由细晶岩至伟晶岩演化过程中,相对分异程度升高,熔体相和富挥发分的流体相之间发生强烈碱交代作用,并在一定的结构分带中发生大规模稀有金属矿化.      

Rare metal-bearing pegmatites from the Southeastern Desert of Egypt： Geology, geochemical characteristics, and petrogenesis

The pegmatite province of the Southeastern Desert (SED) is part of a pegmatite district that extends from Egypt (extends to 1200 km2). Rare metal pegmatites are divided into (1) unzoned, Sn-mineralized; (2) zoned Li, Nb, Ta and Be-bearing; and (3) pegmatites and pegmatites containing colored, gem-quality tourmaline. The Rb/Sr data reflect a crustal origin for the rare metal pegmatites and indicate that the original SED magma was generated during the peak of regional metamorphism and predates the intrusion of post-tectonic leucogranites. These bodies developed an early border zone consisting of coarse to very coarse muscovite quartz alkali feldspar, followed by an intermediate zone of dominant quartz feldspar muscovite rock. Garnet, tourmaline, beryl, galena, pyrite, amblygonite, apatite and monazite are rare accessories in both zones. Cassiterite tends to concentrate in replacement zones and along fractures in albite quartz muscovite-rich portions. The highest concentrations of cassiterite occur in irregular greisenized zones which consist dominantly of micaceous aggregates of green Li-rich muscovite, quartz, albite and coarse-grained cassiterite. The different metasomatic post-solidification alterations include sodic and potassic metasomatism, greisenization and tourmalinization. Geochemically, the pegmatite-generating granites have a metaluminous composition, showing a differentiation trend from coarse-grained, unfractionated plagioclase-rich granite towards highly fractionated fine- to medium-grained, local albite-rich rock. Economically important ore minerals introduced by volatile-rich, rare metal-bearing fluids, either primarily or during the breakdown of the primary mineral assemblages, are niobium-tantalum oxides, Sn-oxides (cassiterite), Li-silicates (petalite, spodumene, euctyptite, and pollucite), Li-phosphates (amblygonite, montebrasite and lithopilite) and minor REE-minerals (Hf-zircon, monazite, xenotime, thorian, loparite and yttrio-fluorite). The pollucite is typically associated with spodumene, petalite, amblygonite, quartz and feldspar. The primary pollucite has Si/Al (at) ratios of 2.53-2.65 and CRK of 79.5- 82.2. Thorian loparite is essentially a member of the loparite (NaLREETi2O6)-lueshite (NaNbO3)-ThTi2O6-ThNb4O12 quaternary system with low or negligible contents of other end-member compositions. The mineral compositionally evolved from niobian loparite to niobian thorian and thorian loparite gave rise to ceriobetafite and belyankinite with high ThO2 contents. Thorian loparite is metamict or partly metamict and upon heating regains a structure close to that of synthetic loparite NaLaTi2O6.