【摘要】：金川巖漿型銅鎳硫化物礦床是在采的世界第三大銅鎳硫化物礦床,金川巖體出露面積僅有1.34km2,礦化率卻高達(dá)47%。金川巖體主要組分成分為鎂鐵質(zhì)巖石,主要造巖礦物為：橄欖石、單斜輝石和斜方輝石。金川巖體中不同巖石類型的橄欖石牌號(hào)Fo值變化范圍小,橄欖石探針分析表明Fo值集中在80～83,暗示金川巖體成礦環(huán)境為開放式的巖漿系統(tǒng),巖漿到達(dá)成礦環(huán)境之后還存在多期次新鮮巖漿的補(bǔ)充貫入。不同粒度巖相以及礦石類型之間的接觸關(guān)系呈突變類型,暗示金川母巖漿上升到現(xiàn)存成礦空間之間即發(fā)生了成礦物質(zhì)的富集作用,即硫化物飽和在侵入就位前就已經(jīng)實(shí)現(xiàn)。硫飽和機(jī)制的研究主要包括：巖漿源區(qū)的判別、巖漿原始組分的厘定、地幔部分熔融程度的厘定、熔融巖漿中硫的含量、影響巖漿硫溶解能力的因素、不同因素的主導(dǎo)能力、巖漿達(dá)到硫化物飽和時(shí)硫的含量等。本文研究表明金川母巖漿源于20%部分熔融程度的富集地幔,微量元素分析表明巖漿在上升過程經(jīng)歷了約15%～-40%的地殼物質(zhì)混染,而硫同位特征顯示金川礦區(qū)中的硫?yàn)獒Ｔ戳?排除了地殼硫的加入的可能。對(duì)巖漿離開源區(qū)時(shí)巖漿中硫的含量進(jìn)行估算為1000ppm,根據(jù)高鎂玄武巖漿SCSS(sulfur content at sulfide saturation,即巖漿達(dá)到硫化物飽和狀態(tài)時(shí)硫的含量)與深度的關(guān)系,金川母巖漿形成時(shí)的SCSS在950ppm-1100ppm,因此金川母巖漿在離開地幔時(shí)是接近其SCSS的�；谝陨戏治鼋Y(jié)果,本文提出金川巖漿實(shí)現(xiàn)硫化物飽和的過程大致如下：金川母巖漿在富集地幔的20%部分熔融作用下形成,形成時(shí)硫的含量大約為1000ppm, SCSS為950ppm～1100ppm,在其上升至就位巖漿房途中經(jīng)歷了約15%-40%地殼物質(zhì)的混染,使得SCSS降至其硫含量之下,進(jìn)而發(fā)生硫化物熔離,并在巖漿房中富集成礦。
[Abstract]:Jinchuan magmatic copper-nickel sulfide deposit is the third largest copper nickel sulfide deposit in the world. The area of Jinchuan rock body is only 1.34 km ~ 2, but the mineralization rate is as high as 47. The main composition of Jinchuan rock body is mafic rock, and the main rock-forming minerals are olivine, clinopyroxene and clinopyroxene. The Fo value of olivine in different rock types in Jinchuan rock mass varies in a small range. The olivine probe analysis shows that the Fo value is concentrated in 80 / 83, suggesting that the metallogenic environment of the Jinchuan rock mass is an open magmatic system. After the magma reaches the metallogenic environment, there are several times fresh magma supplementary penetration. The contact relationship between different granularity lithofacies and ore type is abrupt, suggesting that the enrichment of ore-forming material occurred between Jinchuan magma rising to the existing ore-forming space, that is, sulfide saturation was realized before invading into place. The research on the mechanism of sulfur saturation mainly includes: distinguishing the magmatic source region, determining the original composition of the magma, determining the degree of partial melting of mantle, the content of sulfur in the molten magma, the factors influencing the sulfur dissolution ability of the magma, and the leading ability of different factors. Sulfur content when magma reaches sulphide saturation. This paper shows that Jinchuan mother magma originated from the enriched mantle with 20% partial melting degree. Trace element analysis shows that the magma experienced about 150-40% crustal material mixing in the rising process, while the sulfur isochronal characteristics indicate that the sulfur in Jinchuan mining area is a mantle source. The addition of crustal sulfur is ruled out. The sulfur content in the magma is estimated to be 1000 ppm when the magma leaves the source area. According to the relationship between the sulfur content and the depth of the high magnesium Black Tortoise magma, that is, when the magma reaches the sulphide saturation state, the content of sulfur in the magma is estimated to be 1 000 ppm. The SCSS of Jinchuan mother magma was 950ppm-1100ppm, so the Jinchuan mother magma was close to its SCSS when leaving the mantle. Based on the above analysis results, it is suggested that the process of sulphide saturation of Jinchuan magma is as follows: Jinchuan mother magma is formed by 20% partial melting of enriched mantle. The sulfur content at the time of formation is about 1000 ppmand SCSS is 950ppm-1 100ppm.The sulfur content of SCSS decreases to below its sulfur content during its rise to the in-situ magma chamber, which causes the SCSS to fall below its sulfur content, and then it is enriched in magma chamber for mineralization.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P618.41;P618.63

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 孫赫;唐冬梅;秦克章;范新;肖慶華;蘇本勛;;親銅元素的地球化學(xué)行為研究進(jìn)展及其在巖漿硫化物礦床中的應(yīng)用[J];地質(zhì)論評(píng);2009年06期

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本文編號(hào)：2126684