本文選題：鎢錫鈹?shù)V床 + 成礦流體��； 參考：《成都理工大學(xué)》2015年碩士論文

【摘要】：雪寶頂鎢錫鈹?shù)V床位于四川省平武縣境內(nèi),是松潘-甘孜造山帶和秦嶺造山帶內(nèi)迄今發(fā)現(xiàn)的唯一的鎢錫鈹?shù)V床。本文在前人研究的基礎(chǔ)上,結(jié)合礦床地質(zhì)特征,對(duì)流體包裹體進(jìn)行了巖相學(xué)觀察、顯微測(cè)溫、激光拉曼光譜分析及熱力學(xué)計(jì)算等研究,對(duì)雪寶頂?shù)V床成礦流體的性質(zhì)、來源和成礦機(jī)理取得以下認(rèn)識(shí)：中三疊統(tǒng)雜谷腦組(T2z1)下段為主要的賦礦地層,部分礦體產(chǎn)出于花崗巖體中及其圍巖接觸帶中,礦體以脈狀、網(wǎng)脈狀產(chǎn)出,礦石礦物主要為綠柱石、白鎢礦、錫石及少量的電氣石、黃銅礦、黃鐵礦、方鉛礦、閃鋅礦等。脈石礦物為石英、白云母、鉀長(zhǎng)石、螢石、鈉長(zhǎng)石、磷灰石等。礦石具有脈狀構(gòu)造、網(wǎng)脈狀構(gòu)造、塊狀構(gòu)造和晶簇狀構(gòu)造,自形晶結(jié)構(gòu)、偉晶結(jié)構(gòu)、內(nèi)部環(huán)帶結(jié)構(gòu)。礦床中發(fā)育的包裹體可分為三大類,為熔融包裹體、流體-熔融包裹體、流體包裹體,其中,流體包裹體又可分為氣相H20包裹體、氣液H2O包裹體,氣相CO2包裹體、氣液C02包裹體、富CO2相CO2-H2O包裹體、富H20相CO2-H2O包裹體六類,顯示出成礦流體由巖漿演化分異而來的特征,流體包裹體組合則顯示出不混溶的特征。本礦床氣液H20包裹體的均一溫度為167～255℃,鹽度w(NaCl)為3.39%～6.59%,密度介于0.8g/cm3～1.0g/cm3之間。富CO2相CO2-H2O包裹體,均一溫度范圍234℃～267℃,平均值為250℃；均一壓力范圍124MPa～ 171MPa,平均值為153MPa；密度值變化范圍是0.6781 g/cm3～0.7618g/cm3, CO2的摩爾分?jǐn)?shù)變化范圍為0.6349-0.7407。富H2O相CO2-H2O包裹體的完全均一溫度范圍是224℃～286℃,平均值為251℃；完全均一壓力范圍是122MPa～ 155MPa,平均值為144MPa；密度變化范圍是0.9342g/cm3～0.9655g/cm3, CO2的摩爾分?jǐn)?shù)變化范圍為0.0962-0.1123。兩種類型CO2-H2O包裹體的溫壓一致,它們是同時(shí)捕獲的C02-低鹽水相不混溶包裹體組。成礦流體具有低鹽度、中高密度、富C02的性質(zhì)。氣液H20包裹體和氣液C02包裹體聯(lián)合求壓法計(jì)算得到綠柱石形成溫度為318℃,形成壓力為147MPa；白鎢礦形成溫度為296℃,形成壓力為101MPa。礦床的形成深度約為8.29Km～10.11Km,為高中溫深成礦床。三疊紀(jì)揚(yáng)子板塊與華北板塊發(fā)生碰撞事件,本區(qū)發(fā)生了強(qiáng)烈的構(gòu)造巖漿活動(dòng),花崗巖漿在冷凝結(jié)晶過程中分異出的成礦流體向花崗巖體外部流動(dòng),當(dāng)進(jìn)入節(jié)理裂隙發(fā)育的花崗巖巖體與圍巖(大理巖)的接觸帶時(shí),由于壓力的降低,發(fā)生CO2-H2O流體不混溶作用,導(dǎo)致礦質(zhì)大量沉淀,這是本礦床的主要成因。
[Abstract]:Xuebao Ding tungsten tin beryllium deposit located in Pingwu County Sichuan Province is the only tungsten tin beryllium deposit found in Songpan-Ganzi orogenic belt and Qinling orogenic belt. On the basis of previous studies and combined with the geological characteristics of the deposit, the petrographic observation, micro-temperature measurement, laser Raman spectroscopy analysis and thermodynamic calculation of fluid inclusions are carried out in this paper to study the ore-forming fluid properties of Xuebao Ding deposit. The source and metallogenic mechanism are as follows: the lower part of the Middle Triassic Zagunao formation (T2z1) is the main ore-bearing strata, some orebodies occur in the granite body and its surrounding rock contact zone, and the orebodies are vein-like and net-vein. Ore minerals are mainly Beryl, scheelite, cassiterite and a small amount of tourmaline, chalcopyrite, pyrite, galena, sphalerite and so on. Gangue minerals are quartz, Muscovite, potassium feldspar, fluorite, albite, apatite, etc. The ore has vein structure, net vein structure, block structure and cluster structure, self-shaped crystal structure, pegmatite structure and inner ring structure. The inclusions developed in the deposit can be divided into three categories: melt inclusions, fluid-melt inclusions, fluid inclusions. Among them, fluid inclusions can be divided into gas-phase H20 inclusions, gas-liquid H2O inclusions, gas-phase CO2 inclusions. The gas-liquid CO2 inclusions, CO2 rich CO2-H2O inclusions and H20-rich CO2-H2O inclusions show that the ore-forming fluids come from the evolution of magma, while the fluid inclusions assemblage shows the characteristics of immiscibility. The homogenization temperature of gas-liquid H20 inclusions in the deposit is 167 ~ 255 鈩，

本文編號(hào)：2066243