本文關(guān)鍵詞： 小加山 石英脈型鎢礦 成礦流體 地球化學(xué) 遠(yuǎn)景評價　出處：《北京科技大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：小加山鎢礦床位于新疆巴里坤地區(qū),屬石英脈型鎢礦床。該區(qū)基礎(chǔ)地質(zhì)資料缺少,勘查工作程度低,成因研究薄弱,制約了成礦機(jī)理研究的深度。本文在地質(zhì)特征基礎(chǔ)上,對小加山鎢礦床不同類型的含鎢石英脈開展巖相學(xué)、流體包裹體研究,通過巖體地球化學(xué)特征討論礦化蝕變特點(diǎn),查明成礦流體來源,獲得成因認(rèn)識,分析成礦作用,總結(jié)成礦規(guī)律。礦區(qū)位于東準(zhǔn)噶爾成礦區(qū)中部南緣,處于博格達(dá)-哈爾里克構(gòu)造帶上。構(gòu)造位置上礦區(qū)處于哈爾里克復(fù)式背斜中,構(gòu)造線方向以EW向為主。礦區(qū)出露地層主要為中泥盆統(tǒng)大南湖組第一亞組第一段(D2d11)、第二段(D2d12)。主要巖漿巖有石英閃長巖、黑云母花崗巖、鉀長花崗巖及少量中酸性花崗閃長巖脈。礦體賦存于鄰近海西晚期花崗巖侵入體附近的中泥盆統(tǒng)大南湖組第一亞組第二段(D2d12)的變質(zhì)晶屑凝灰?guī)r中。與成礦有關(guān)的小加山侵入巖體主要巖石類型為黑云母花崗巖,其圍巖主要為蝕變閃長巖和變晶屑凝灰?guī)r。該花崗巖屬于高鉀鈣堿性準(zhǔn)鋁質(zhì)—A型花崗巖,巖體均屬于輕稀土富集型。微量元素特征揭示出巖漿成巖的過程中可能發(fā)生強(qiáng)烈地分離結(jié)晶作用,巖漿物質(zhì)來源可能與富集巖石圈地幔有關(guān)�；◢弾r為后碰撞伸展花崗巖區(qū),巖體形成于伸展構(gòu)造環(huán)境,是后碰撞環(huán)境下巖漿活動的產(chǎn)物。黑鎢礦石英脈分為灰色含鎢石英脈和白色含鎢石英脈兩種。巖相學(xué)觀察含礦石英脈中流體包裹體主要為兩相水溶液包裹體,EW走向的灰色石英脈包裹體氣液比大,SN走向的白色石英脈包裹體氣液比較小。顯微測溫結(jié)果顯示灰色石英脈均一溫度(Th)范圍為143～354℃,白色石英脈Th范圍為154～312℃。激光拉曼探針顯示小加山鎢礦含黑鎢礦石英脈中流體包裹體含有少量CO2組分。H、O同位素研究表明：鎢礦床成礦流體來源以巖漿水為主。成礦演化過程為：巖漿巖侵入活動→巖漿水運(yùn)移分離→含鎢絡(luò)合物遷移搬運(yùn)→冷卻富集成礦,成礦晚期流體有大氣降水的混合。受海西期構(gòu)造活動影響,鎢的花崗質(zhì)巖漿自下而上發(fā)生侵入,花崗巖高度分異演化,冷凝后形成黑云母花崗巖,富含W元素巖漿熱液過渡性流體沿裂隙向上流動,在上部地層中引發(fā)硅化和絹云母化,隨著成礦流體溫度降低,含鎢絡(luò)合物分解,形成了石英脈型黑鎢礦床。結(jié)合鎢礦床的礦物共生組合和圍巖蝕變特征、成礦流體和巖漿作用等研究結(jié)果,認(rèn)為小加山鎢礦床與贛南鎢礦構(gòu)造環(huán)境具有相似性,可能存在“三層摟”結(jié)構(gòu),從而建立了成礦模式。進(jìn)行了化探數(shù)據(jù)W、Mo含量等值線圖分析,綜合地質(zhì)特征以及東南礦點(diǎn)和化工西礦區(qū)W、Mo含量等值線與異常帶吻合區(qū)域,反映出東南礦點(diǎn)和化工西礦區(qū)深部和外圍存在鎢礦潛力很大。
[Abstract]:The Xiaojiashan tungsten deposit is located in the Balikun area of Xinjiang and belongs to the quartz vein tungsten deposit. The basic geological data are scarce, the exploration work is low and the genetic study is weak in this area, which restricts the depth of the study of metallogenic mechanism. The petrographic and fluid inclusions of different types of tungsten bearing quartz veins in the Xiaojiashan tungsten deposit are studied. Through the geochemical characteristics of the rock mass, the characteristics of mineralization and alteration are discussed, the source of the ore-forming fluid is found, the genetic understanding is obtained, and the metallogenic process is analyzed. The ore area is located in the southern margin of the middle part of the East Junggar metallogenic deposit, and is located in the Bogda-Halrick structural belt. The main direction of the tectonic line is EW. The exposed strata of the mining area are the first member of the first subformation of the Dananhu formation of the Middle Devonian, the first member of the first subformation, and the second stage of the second member of the D2d12. The main magmatic rocks are quartz diorite and biotite granite, and the main magmatic rocks are quartz diorite and biotite granite. Potassium feldspar granodiorite and a small amount of intermediate-acid granodiorite diorite. The orebody occurs in metamorphic tuff tuff of the first sub-formation of the Dananhu formation in the Middle Devonian near the late Hercynian granite intrusion. The main rock types of Xiaogashan intrusive body are biotite granite. The surrounding rocks are mainly altered diorite and metamorphic tuff. The characteristics of trace elements indicate that the magmatic diagenesis may have strong separation and crystallization, and the source of magmatic material may be related to the enriched lithospheric mantle. The granite is a post-collisional extensional granite area. The rock mass was formed in an extensional tectonic environment, The quartz vein of wolframite is divided into gray tungsten quartz vein and white tungsten bearing quartz vein. The gas-liquid content of gray quartz vein inclusions is smaller than that of white quartz vein inclusions with large SN strike. The results of microthermometry show that the homogenization temperature of grey quartz veins is in the range of 143 ~ 354 鈩，

本文編號：1541034