發(fā)布時(shí)間：2018-01-17 16:41

  本文關(guān)鍵詞：大興安嶺北段爭(zhēng)光金礦地質(zhì)特征及成礦機(jī)制研究　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 流體包裹體 C-H-O-He-Ar同位素 黃鐵礦微量元素 爭(zhēng)光金礦床 大興安嶺

【摘要】：爭(zhēng)光淺成低溫?zé)嵋盒徒鸬V床位于大興安嶺成礦帶北段,是多寶山礦集區(qū)內(nèi)的一個(gè)重要礦床。本文對(duì)該礦床的地質(zhì)特征、全巖及微區(qū)地球化學(xué)、成礦流體、同位素示蹤等方面進(jìn)行了系統(tǒng)研究,取得的主要成果如下:(1)前人研究的鋯石LA-ICP-MS U-Pb測(cè)年數(shù)據(jù)表明,爭(zhēng)光金礦閃長(zhǎng)巖形成于晚侏羅世(151Ma)。本文巖石地球化學(xué)特征顯示,爭(zhēng)光閃長(zhǎng)巖屬準(zhǔn)鋁質(zhì)鈣堿性巖石,具有富Fe、Ca、Al和Mg、貧Na和K、富集大離子親石元素和輕稀土元素、虧損高場(chǎng)強(qiáng)元素和重稀土元素、Eu異常不明顯的特點(diǎn)。上述特征表明,爭(zhēng)光閃長(zhǎng)巖由俯沖流體交代的地幔楔部分熔融形成。(2)流體包裹體研究表明,爭(zhēng)光金礦床主要發(fā)育富液兩相包裹體。流體包裹體均一溫度介于116~294℃之間,鹽度w(NaCleq)為0.9%~13.8%。石英流體包裹體的δD和δ18O分別為-127‰~-110‰和-5.9‰~0.6‰。方解石的δ13C和δ18O分別為-5.3‰~-2.0‰和7.7‰~13.5‰。黃鐵礦流體包裹體的3He/4He、40Ar/36Ar和40Ar*/4He比值分別為1.75~3.06Ra、683~1295和0.30~0.63。流體包裹體和穩(wěn)定同位素特征顯示,成礦早階段成礦流體為大氣降水與圍巖發(fā)生水-巖反應(yīng)后的演化水。隨著成礦作用的進(jìn)行,成礦流體變?yōu)榇髿饨邓c巖漿水的混合水。(3)通過(guò)礦相學(xué)研究、掃描電鏡觀察和能譜分析,查明該礦床金礦物種類主要為銀金礦、金銀礦、自然金和碲金銀礦。金的賦存狀態(tài)為粒間金、裂隙金、包裹金和固溶體金。(4)黃鐵礦電子探針和微區(qū)原位LA-ICP-MS測(cè)試結(jié)果顯示,該礦床黃鐵礦Fe和S的含量變化較小,但是Au、Ag、As、Se、Co、Ni在不同類型黃鐵礦中的含量存在差異。黃鐵礦的Co/Ni值為0.04~318.36(平均為20),Se含量為0.100~395.3ppm(平均為63),是典型的熱液成因黃鐵礦。Au未飽和的成礦流體與貧H2S的流體混合是該礦床金沉淀的主要機(jī)制。(5)爭(zhēng)光金礦床的形成與閃長(zhǎng)巖有著密切聯(lián)系。閃長(zhǎng)巖不僅是成礦流體和成礦物質(zhì)的主要來(lái)源,還為成礦流體的對(duì)流循環(huán)提供了熱能。
[Abstract]:The Gengguang epithermal hydrothermal gold deposit is located in the northern section of the Daxinganling metallogenic belt and is an important deposit in the Dobaoshan ore concentration area. This paper deals with the geological characteristics of the deposit, the geochemistry of the whole rock and microregion, and the ore-forming fluid. The main results obtained are as follows: 1) the zircon U-Pb dating data obtained by previous studies show that the zircon U-Pb dating results are as follows. The diorite of Zhengguang gold deposit was formed in the late Jurassic (151Ma). The geochemical characteristics of this paper show that the diorite is a kind of quasi-aluminous calc-alkaline rock, which is rich in Fe ~ (2 +) Ca ~ (2 +) Al and mg. The characteristics of poor Na and K, enrichment of large ion lithophile elements and light rare earth elements, depletion of high field strength elements and heavy rare earth element EU anomalies are not obvious. The study of fluid inclusions from the subducted fluid metasomatic mantle wedge formed by partial melting of the glowing diorite. Liquid rich two-phase inclusions are mainly developed in Zhengguang gold deposit. The homogenization temperature of fluid inclusions is between 116 ~ 294 鈩，

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