Revealing mineralization and subsequent hydrothermal events: Insights from 40Ar/39Ar isochron and novel gas mixing lines of hydrothermal quartzs by progressive crushing
Revealing mineralization and subsequent hydrothermal events: Insights from 40Ar/39Ar isochron and novel gas mixing lines of hydrothermal quartzs by progressive crushing
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揭示矿化和随后的热液事件：Ar-40/Ar-39 等时线的见解以及通过渐进式破碎的热液石英的新型气体混合线
DOI：
10.1016/j.chemgeo.2018.02.039
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发表时间：
2018-04-20
期刊：
影响因子：
3.9
通讯作者：
Qiu, Hua-Ning
中科院分区：
文献类型：
--
作者：
Bai, Xiu-Juan;Jiang, Ying-De;Qiu, Hua-Ning
越来越多的资料表明，40 Ar/39 Ar破碎技术为热液矿床的成矿年龄测定提供了一种非常有用的方法。在这项研究中，新的气体混合线提出了基于数据的两个石英样品的40 Ar/39 Ar粉碎。电子探针分析表明，石英颗粒含有富钾硅酸盐微晶。两种石英的破碎产生两条混合线，其年龄分别对应于钾长石或绢云母（成矿后流体）和白云母样品（成矿流体）。这是第一次用富钾矿物的年龄来确定次生和原生流体包裹体的年龄。研究结果表明，40 Ar/39 Ar破碎技术在确定流体活动年龄方面是非常有用的。新提出的气体混合模式在逆等时图和正等时图上显示为：（1）在不同的破碎阶段，混合物中PFI和SFI的比例不同：（2）气体混合线产生的PFI年龄具有较低的初始40 Ar/Ar-36比值;（3）不能获得PFI和SFI年龄之间的中间年龄，因为渐进破碎技术从不释放具有恒定PFI的气体混合物。每一步的SFI比例。因此，气体混合线被解释为产生重要的地质年龄。混合模式有助于更好地理解40 Ar/39 Ar定年结果，并可为其它同位素混合等时线系统提供参考。
Increasingly more data have indicated that the 40Ar/39Ar crushing technique provides a very useful approach to determine the mineralization ages of hydrothermal ore deposits. In this study novel gas mixing lines are proposed based on the data of two quartz samples by 40Ar/39Ar crushing. Electron microprobe analyses indicate that the quartz grains contain K-rich silicate microlites. Both quartzs by crushing yield two mixing lines with ages corresponding respectively to those of K-feldspar or sericite (post-mineralization fluids) and muscovite samples (ore-forming fluids). This is the first report that both ages of secondary and primary fluid inclusions (SFIs and PFIs) are confirmed correspondingly by those of the K-rich minerals. This study strongly indicates that the 40Ar/39Ar crushing technique is very useful to determine the ages of geofluid activities. The newly proposed gas mixing patterns are shown on the inverse and normal isochron diagrams, indicating: (1) the mixtures are in different proportions of the PFIs and SFIs in different crushing steps; (2) the gas mixing lines yield PFI ages with low initial 40Ar/Ar-36 ratios; (3) an intermediate age between PFI and SFI ages cannot be obtained because the progressive crushing technique never release gas mixtures with a constant PFI/SFI proportion for each step. The gas mixing lines are thus interpreted to yield significant geological ages. The mixing patterns will help us better understand the 40Ar/39Ar dating results and be used for references to other isotopic mixing isochron systems.