東昆侖夏日哈木鎳銅硫化物礦床成礦巖漿條件:流體揮發(fā)份化學(xué)組成與碳同位素組成制約
發(fā)布時(shí)間:2018-03-22 17:44
本文選題:來源 切入點(diǎn):碳同位素 出處:《巖石學(xué)報(bào)》2017年01期 論文類型:期刊論文
【摘要】:夏日哈木鎳銅硫化物礦床是我國東昆侖造山帶新發(fā)現(xiàn)的全球島弧環(huán)境最大的巖漿鎳銅硫化物礦床。早泥盆世鎂鐵-超鎂鐵質(zhì)成礦巖體中不同類型巖石的輝石中流體揮發(fā)份化學(xué)組成和碳同位素組成表明,流體揮發(fā)份總量較低,平均含量為888mm~3.STP/g(STP:標(biāo)準(zhǔn)溫度和大氣壓)。流體揮發(fā)份組成以H_2O為主(48mol%),其次為H_2(26%)、CO_2(15%)和CO(5%)。H_2S含量從二輝橄欖巖(10mm~3/g)、橄欖輝石巖(18mm~3/g)到二輝輝石巖(28mm~3/g)逐漸增加,表明巖漿就位結(jié)晶演化過程中含硫組分的加入。CO_2的δ~(13)C值(-23.5‰~-5.0‰)位于地殼和地幔值范圍之間。CH_4同系物碳同位素組成隨碳數(shù)具有總體正序、局部反序的分布特征,顯示大洋沉積有機(jī)質(zhì)熱裂解成因特征。夏日哈木成礦鎂鐵-超鎂鐵質(zhì)巖體流體組分中較低的H2_O含量和較高的H_2含量表明,巖漿演化處于還原性揮發(fā)份條件,地幔巖漿源區(qū)存在俯沖洋殼沉積有機(jī)質(zhì),巖漿房圍巖的混染和富S流體的加入可能是夏日哈木巖漿鎳銅硫化物礦床硫飽和的主要機(jī)制。
[Abstract]:The summer Hamu nickel-copper sulfide deposit is the largest magmatic Ni-Cu sulfide deposit in the island arc environment of the East Kunlun orogenic belt in China. Pyroxene midstream of different types of rocks in the early Devonian magnesia-ultramafic ore-forming body. The chemical composition and carbon isotopic composition of body volatiles indicate that, The total amount of fluid volatilization is relatively low, the average content is 888mm / 3.STP: standard temperature and atmospheric pressure. The volatile composition of the fluid is mainly composed of H2O (48mol / g), followed by H226Stud (Co21515g) and CO(5%).H_2S (from 10mm / 3 / g, 18mm / 3g) to 2828mm / 3g / g, respectively, and the content of CO(5%).H_2S increases gradually from 10mm / g to 2828mm / 3g / g, and the content of CO(5%).H_2S increases gradually from 10mm / g to 2828mm / 3g / g, and the content of CO(5%).H_2S increases from 10mm / g to 2828mm / g / g, respectively. The results show that the sulfur components of the magma in the process of crystallization evolution of the magma have the distribution characteristics of total positive sequence and local inverse sequence with the addition of sulfur component. COSP _ 2 (未 -23.5 鈥,
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