甘肃文县阳山金矿成矿物质及成矿流体来源的稳定同位素约束  

Stable isotope constraints of ore-forming materials and sources of oreforming fluids in the Yangshan gold deposit, Wenxian County,Gansu Province

作　　者：李璇 也尔哈那提 马万里 马锦龙 Li Xuan;Ye'erhanati;Ma Wan-li;Ma Jin-long(Key Laboratory of Mineral Resources in Western of Gansu Provience,School of Earth Sciences,Lanzhou University,Lanzhou 730000,China;Karamay Vocational and Technical College,Karamay 834000,Xinjiang,China)

机构地区：[1]兰州大学地质科学与矿产资源学院,甘肃省西部矿产资源重点实验室,兰州730000 [2]克拉玛依职业技术学院,新疆克拉玛依834000

出　　处：《兰州大学学报（自然科学版）》2021年第1期1-7,共7页Journal of Lanzhou University(Natural Sciences)

基　　金：国家自然科学基金项目(41173014)。

摘　　要：以甘肃文县阳山金矿系秦岭集矿区的一处大型金矿床主要载金矿物黄铁矿为研究对象,对同一样品进行S、C、He、Ar同位素测定,以研究成矿物质及成矿流体来源.结果表明,斜长花岗斑岩中黄铁矿的δ^(34)S=0.1‰~0.5‰,主要集中在0.1‰~0.2‰,显示硫的深部来源;千枚岩中黄铁矿的δ^(34)S=3.768‰~9.496‰,与沉积硫范围一致,可能与赋矿地层碧口群有关;不同类型岩石中黄铁矿δ^(13)C=-32.530‰~9.867‰,分布范围广且较为离散,包括有机碳来源、沉积碳来源及岩浆碳来源,显示成矿流体具有多源性;黄铁矿n(^(3)He)/n(^(4)He)平均值0.123R_(a)(范围0.06~0.28R_(a), R_(a)为大气n(^(3)He)/n(^(4)He)值,R_(a)=1.39×10^(-6)),稍高于地壳特征值(0.01~0.05R_(a));n(^(40)Ar)/n(^(4)He)=0.16~0.34,与地幔特征值(0.33~0.56)有一定交集;n(^(40)Ar)/n(^(36)Ar)平均值448.3,高于大气饱和水,计算表明其由2.64%~51.06%的壳源^(40)Ar和41.06%~97.36%的大气^(40)Ar构成.阳山金矿成矿物质反映了赋矿地层的重要贡献,有部分深部来源特点;成矿流体在深部以岩浆流体与变质流体为主,随着深度的变浅,大气水逐渐成为成矿流体的主体.The main gold-bearing mineral pyrite in the mining area of the Yangshan gold deposit in Wenxian County, Gansu Province, a large deposit in the Qinling concentration area, was taken as the research object. S, C, He, and Ar isotopes of the same sample were used to limit the sources of ore-forming materials and ore-forming fluids;the main gold-bearing pyrite in the mining area was taken as the research object for a determination of S, C, He and Ar. The results showed that δ^(34)S value of pyrite in the plagiogranite porphyry varied from 0.1‰ to 0.5‰, mainly concentrated in 0.1‰-0.2‰ and showing a deep source of sulfur;the δ^(34)S value of pyrite in phyllite ranged from 3.768‰ to 9.496‰, which was consistent with the range of deposited sulfur, possibly with ore-bearing strata and related to the mouth group;the δ^(13)C value of pyrite in different types of rocks was-32.530‰-9.867‰, which was widely distributed and discrete, including organic carbon source, sedimentary carbon source and magmatic carbon source, indicating that the ore-forming fluid was of a multi-source;the n(^(3)He)/n(^(4)He) average of pyrite was 0.123 R_(a)(range 0.06-0.28 R_(a)), slightly higher than the crustal characteristic value(0.01-0.05 R_(a));n(^(40)Ar)/n(^(4)He)value was between 0.16-0.34, with the mantle characteristic value being(0.33-0.56). There was a certain intersection;n(^(40)Ar)/n(^(36)Ar) average 448.3, the high atmospheric saturated water was calculated to be consisting of 2.64%-51.06% shell source^(40)Ar and 41.06%-97.36% of the atmosphere^(40)Ar. The ore-forming materials of the Yangshan gold deposit mainly reflected an important contribution of the ore-bearing strata and some of the deep source characteristics. The ore-forming fluids were mainly of a magmatic and metamorphic nature in the deep. As the depth became shallower, atmospheric water gradually turned to be the main body of the ore-forming fluids.

关 键 词：流体包裹体 稳定同位素 稀有气体同位素 阳山金矿 

分 类 号：TU18[建筑科学—建筑理论]