【作者】 户双节；

【导师】 梁斌； 付小方；

【作者基本信息】 西南科技大学 ， 地质工程（专业学位）， 2018， 硕士

【摘要】 川西甲基卡花岗伟晶岩型稀有金属矿区是我国目前发现的规模最大的稀有金属矿区,同时也是最大的固体锂矿区,具有Be-Li-Nb、Ta成矿系列。本文通过对新发现的X03号超大型锂辉石伟晶岩矿床以及NO.528号铌钽伟晶岩矿床的矿床地质特征、稀有金属赋存状态与富集规律、围岩蚀变特征以及找矿标志进行分析研究,为指导该区进一步找矿提供理论依据。获得的主要认识有:1、X03号锂辉石伟晶岩脉和NO.528号铌钽型伟晶岩脉分别位于IV、V型伟晶岩带中,其不同类型伟晶岩脉体在空间上严格受控于二云母花岗岩。X03号脉受成穹后期张性裂隙控制,由多期次(三期)脉动式充填交代形成,矿体分带性差。NO.528号脉则受同构造作用(右旋张扭性裂隙)控制,矿体分带性好。2、X03及NO.528号脉体均属分异程度高的低钾-钙碱性强过铝质花岗岩。稀土含量均低,平均值分别为12.43、5.74,轻重稀土的配分模式为:轻稀土富集、重稀土亏损的右倾模式。X03号Li矿脉中δEu显示为弱的负铕异常,NO.528号矿体中富Nb、Ta部分地段显示弱的正铕异常,X03号脉及NO.528号脉δCe则大部分均具弱-中等负铈异常。3、X03及NO.528号脉,Li主要赋存于锂辉石中,其次为铁锂云母,然后为Li-多硅白云母、白云母,其它矿物中Li含量较少;Nb、Ta主要集中于铌钽矿物中,其中X03号脉体中主要为铌锰矿,NO.528号脉体中主要为钽锰矿,铌钽其次主要赋存在锡石及白云母中,且NO.528号不同结构带中白云母中Ta含量有由矿体外至内增高的趋势,Nb含量则相反,其它稀有元素含量均较少,仅可作为伴生矿物综合利用。4、X03号脉中不同类型伟晶岩中稀有金属未表现有随世代早晚有增减的趋势,整体呈震荡变化。从矿体空间上看:沿矿体走向上,Li、W、Sn含量在矿体北段相对于南段较富集,Nb、Ta、Rb则相反,Be、Cs含量较均匀。沿矿体倾向上,仅矿体北段Li沿矿体倾向上有增高的趋势。沿矿体厚度方向上,仅Li在2号勘探线中,有呈中间高,两边低的趋势。NO.528号脉体中,Nb、Ta含量由外带细晶岩至内带伟晶岩急剧增高,且矿体下盘中Nb、Ta含量大多高于上盘。矿体内仅内带部分达到工业边界品位,矿体整体较贫。5、X03及NO.528号脉近脉围岩均有电气石化角岩带和堇青石化带,且蚀变带宽度、蚀变矿物含量均与脉体的规模、产状、距脉远近等有一定的联系。岩石化学分析表明,围岩中Li、Rb、Cs、B、F等元素大致有距脉愈远,含量愈低的特点,但各晕带的强度不一,Li晕最强,其它晕带均较弱。6、通过对甲基卡典型稀有金属伟晶岩矿床的研究,系统总结了成矿地质特征以及找矿标志。基于此,划分出了两个稀有金属找矿远景区,即甲基卡矿区外围东部及东北部和甲基卡外围北部德哲科。更多还原

【Abstract】 It is the largest rare metal mining area in China,and also the largest solid lithium mining area,which has the Be-Li-Nb and Ta metallogenic series.To provide theoretical basis for futher prospecting in this area,this paper analyzed and studied the ore deposit geological characteristics,rare metal occurrence state and enrichment regularity,wall rock alteration characteristics and prospecting marks of the newly discovered X03 superlarge spodumene pegmatite deposit an NO.528 ninbium-tantalum pegmatite deposit.The main knowledge gained is:1、The spodumene type pegmatic vein of X03 and the niobium tantalum type pegmatic vein of NO.528 is located in IV and V-shaped pegmatite zone,the different types of pegmatite veins are strictly controlled in space by two mica granite.The X03 vein is controlled by the late tensional fractures of the vault,it is formed by the multi-stage(three stage)pulsating filling replacement and the ore body has poor zoning.The NO.528 is controlled by the same tectonics(right-handed torsional fracture),and the orebody is well distributed.2、The both X03 and NO.528 are granite of low potassium-calcium alkalis with high degree of differentiation.The rare earth content is low,with the average value of 12.43 and 5.74 respectively,and the distribution mode of rare earth is:light rare earth enrichment and the right model of heavy rare earth loss.The δEu of the X03 vein displayed as weak negative europium anomaly,The part of the rich Nb、Ta shows a weak positive europium anomaly in the NO.528 vein.TheδCe is most are weak-medium negative cerium anomaly in X03 vein and NO.528 vein.3、According to the analysis of the main mineral composition of X03 and NO.528 vein,Li is mainly found in spodumene,followed by zinnwaldite 、Li-phengite and muscovite,other minerals contain less;Nb and Ta are mainly concentrated in niobium tantalum minerals,then mainly found in cassiterite and muscovite.The main niobium tantalum minerals of X03 vein is mangancolumbite,the NO.528 is mainly manganotantalite.In addition,the content of Ta inmuscovite in the different structure belt of NO.528 has a tendency of increasing from outside ore body to inside,the Nb content is opposite to the Ta.Other rare elements are so less that can only be used as associated minerals for comprehensive utilization.4、The rare metals in different types of pegmatites in X03 are not showing the trend of increasing or decreasing with the time of generation,the whole is oscillating.From the perspective of ore body space,the contents of Li,W and Sn are relatively rich in the north part of the ore body along the toeards of the ore body.In contrast,The content of Nb,Ta and Rb is the opposite,and the content of Be and Cs is relatively homogeneous.Along the tendency of the ore body,there is an increasing tendency of Li in the north of the ore.In the direction of the thickness of the ore body,Li only has a middle height and a low trend on both sides at No.2 line.In NO.528,the contents of Nb and Ta were significantly increased from the outer zone of fine grained rock to inner pegmatite,and the contents of Nb and Ta in the lower plate of the ore body were mostly higher than that of the upper plate.The ore body is so poorer that just the inner part reaches to the industrial boundary grade.5、All the near vein surrounding rocksof X03 and NO.528 veins have the tourmaline belt and cordiolite belt,and the width of alteration belt and the mineral content of alteration are all related to the size,attitude and distance of the veins.Based on the analysis of rock chemical,it is suggested that the contents of Li、Rb、Cs、B、F of the surrounding rock are decreased with the increasing distance far away from the vein material,but there is a diffenent intensity between each halo zone,the Li halo is strongest,others are weaker.6、Through the study of the typical rare metal pegmatite deposit,the ore for ming geological features and the ore-hunting indicators were systematically su mmarized.Based on this,two rare metallogenic promising prospecting areas wer e identified,it contains the eastern and northeastern part of the periphery of jiaji ka mining area,and dezeke which is north of the periphery of jiajika.更多还原