Zinc, cadmium and sulphur isotopic compositions reveal biological activity during formation of a volcanic-hosted massive sulphide deposit
Zinc, cadmium and sulphur isotopic compositions reveal biological activity during formation of a volcanic-hosted massive sulphide deposit
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锌、镉和硫同位素组成揭示了火山块状硫化物矿床形成过程中的生物活性
DOI：
10.1016/j.gr.2021.07.024
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发表时间：
2022
影响因子：
6.1
通讯作者：
Chuanwei Zhu
中科院分区：
文献类型：
--
作者：
Zhen Yang;Wenrui Song;Hanjie Wen;Yuxu Zhang;Haifeng Fan;Fei Wang;Qiankun Li;Tao Yang;Zhengbing Zhou;Shili Liao;Chuanwei Zhu
锌、镉同位素在一系列热液体系中表现出强烈的分形特征，因此，金属稳定同位素已被用来研究热液矿床的形成。本文研究了内蒙古小坝梁石炭-二叠纪铜金存款矿床硫化物的Zn-Cd-S同位素组成。该古海底热液系统是中亚造山带唯一已知的塞浦路斯型火山岩型块状硫化物（VHMS）存款。硫化物矿物的硫同位素组成变化很大，δ 34 SCDT值为−21.2‰ ~ 25.2‰。我们推断负的δ 34 SCDT值反映了火山成因的S和来自细菌硫酸盐还原（BSR）的S的混合，而正的δ 34 SCDT值反映了火山成因的S和来自热化学硫酸盐还原（TSR）的S的混合。存款锌同位素组成相对一致，δ 66 Zn值为0.10‰ ~ 0.70‰。这些数值与报告的现代海底硫化物数值相似。我们推断δ 66 Zn值的一致性与硫化物沉淀过程中成矿流体中存在的Zn物种（[ZnCl 4]2−）有关。所有硫化物都富含轻Cd同位素，δ114/110 Cd值介于−0.74‰至−0.08‰之间。生物活动对锌和镉的影响很大，推测生物活动导致该存款δ114/110 Cd值为负值的原因是：（1）生物作用（如，（2）由于矿石和玄武岩中Cd的含量远低于Zn，成矿流体中Cd同位素组成容易发生改变。我们的研究结果表明，镉同位素可能记录古老的生物活动，生物体可能发挥更重要的作用比以前认为的VHMS系统的形成。
Zinc and Cd isotopes fractionate strongly within a range of hydrothermal systems; consequently, metal stable isotopes have been used to understand the formation of hydrothermal ore deposits. We investigated the Zn–Cd–S isotopic compositions of sulphides from the Carboniferous-Permian Xiaobaliang Cu–Au deposit, Inner Mongolia, China. This ancient seafloor hydrothermal system is the only known Cyprus-type volcanic-hosted massive sulphide (VHMS) deposit in the Central Asian Orogenic Belt. The S isotopic compositions of sulphide minerals are highly variable with δ34SCDTvalues ranging from −21.2‰ to 25.2‰. We infer that negative δ34SCDTvalues reflect mixing of volcanogenic S and S derived from bacterial sulphate reduction (BSR), and that positive δ34SCDTvalues reflect mixing of volcanogenic S with S derived from thermochemical sulphate reduction (TSR). Zinc isotopic compositions are relatively consistent at the deposit; δ66Zn values range from 0.10‰ to 0.70‰. These values are similar to those reported for modern seafloor sulphides. We infer that consistency of δ66Zn values relates to the Zn species ([ZnCl4]2−) present in the ore-forming fluids during sulphide precipitation. All of the sulphides are enriched in the light Cd isotopes; δ114/110Cd values range from −0.74‰ to −0.08‰. Zinc and Cd can be affected by biological activity, and we infer that biological activity caused the negative δ114/110Cd values at this deposit because: (1) biological processes (e.g., bacterial activity) enrich fluids in the light Cd isotopes, leading to the precipitation of sulphides with negative δ114/110Cd values; and (2) the Cd isotopic composition of ore-forming fluid is readily modified because the concentration of Cd is much lower than that of Zn in ore and basalt. Our results indicate that Cd isotopes might record ancient biological activity, and that organisms might play a more important role than previously thought in the formation of VHMS systems.
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中国西南富勒密西西比河谷型矿床镉同位素分馏
影响因子：
4.8
作者：
Zhu Chuanwei;Wen Hanjie;Zhang Yuxu;Fu Shaohong;Fan Haifeng;Cloquet Christophe
通讯作者：
Cloquet Christophe
DOI：
--
发表时间：
2003-12
期刊：
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影响因子：
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影响因子：
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作者：
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影响因子：
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作者：
W. Shanks
通讯作者：
W. Shanks
影响因子：
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作者：
Ze‐Zhou Wang;Sheng‐Ao Liu;Jingao Liu;Jian Huang;Yan Xiao;Zhuyin Chu;Xinmiao Zhao;Limei Tang
通讯作者：
Ze‐Zhou Wang;Sheng‐Ao Liu;Jingao Liu;Jian Huang;Yan Xiao;Zhuyin Chu;Xinmiao Zhao;Limei Tang