Mercury (Hg) is a volatile, bioaccumulative, and toxic heavy metal, and its global distribution is controlled by the Hg biogeochemical cycle in the atmosphere-land-ocean systems and the deep Hg cycle in interior reservoirs (e.g., mantle and crust). The biogeochemical cycle has been relatively well studied, but the deep Hg cycle remains relatively poorly constrained. Mercury isotopes undergo mass-dependent fractionation (MDF) and unique mass-independent fractionation (MIF) which can provide good constraints on large-scale Hg cycling. In this review, we provide a summary of available results on Hg abundance and isotopic composition in the atmosphere-land-ocean systems and interior reservoirs, with a focus on linking the Hg biogeochemical cycle to the deep Hg cycle. Through this effort, a few key points can be pointed out: (1) Natural and anthropogenic activities release large amounts of Hg into the atmosphere, which is transported on a global scale and deposited in terrestrial and marine systems; (2) Major constituents of the mantle and crust, e.g., mid-ocean ridge basalts (MORBs) and granites, show much lower Hg abundance than the atmosphere-land-ocean systems due to volcanic Hg(0) degassing and the formation of Hg-bearing ore deposits; (3) Mercury isotopes, especially ΔHg values, are useful in tracing surface Hg recycling into mantle and crust; (4) Hg(II) photo-reduction in the atmosphere yields negative ΔHg values in gaseous Hg(0) and positive ΔHg values in Hg(II) species, which results in negative ΔHg values in terrestrial systems (dominant deposition of Hg(0)) and positive ΔHg values in marine systems (dominant deposition of Hg(II); (5) MORBs and arc-related basalts (IABs) show positive ΔHg values, suggesting marine Hg recycling into the oceanic crust and upper mantle via plate subduction. Oceanic island basalts (OIBs) and continental flood basalts (CFBs) mostly display near-zero ΔHg values, suggesting limited surface Hg recycling into the lower mantle. Granites show positive to negative ΔHg values, suggesting the continental crust receives Hg from the metasomatized mantle and remelted terrestrial material. Opposing ΔHg values in arc-related and intracontinental hydrothermal systems highlights the great potential of using Hg isotopes for metallogenic tracing.

中文翻译：

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将汞生物地球化学循环与深层汞循环联系起来：汞同位素视角

汞（Hg）是一种挥发性、生物累积性和有毒重金属，其全球分布受大气-陆地-海洋系统中的汞生物地球化学循环和内部储层（如地幔和地壳）中的深层汞循环控制。生物地球化学循环已经得到了相对充分的研究，但深层汞循环仍然受到相对较少的限制。汞同位素经历质量相关分馏（MDF）和独特的质量无关分馏（MIF），这可以为大规模汞循环提供良好的限制。在这篇综述中，我们总结了大气-陆地-海洋系统和内部储层中汞丰度和同位素组成的现有结果，重点是将汞生物地球化学循环与深层汞循环联系起来。通过这一努力，可以指出以下几个要点：（1）自然和人为活动向大气中释放大量汞，这些汞在全球范围内迁移并沉积在陆地和海洋系统中； (2) 由于火山 Hg(0) 脱气和 Hg 的形成，地幔和地壳的主要成分，如大洋中脊玄武岩 (MORBs) 和花岗岩，其 Hg 丰度远低于大气-陆地-海洋系统。 -含矿床； (3) 汞同位素，特别是ΔHg值，可用于追踪地幔和地壳中的地表汞循环； (4) 大气中的 Hg(II) 光还原在气态 Hg(0) 中产生负 ΔHg 值，在 Hg(II) 物质中产生正 ΔHg 值，从而导致陆地系统中产生负 ΔHg 值（主要沉积为 Hg(0)） ））和海洋系统中的正ΔHg值（主要沉积为Hg（II）；（5）MORB和与弧相关的玄武岩（IABs）显示正ΔHg值，表明海洋汞通过板块俯冲再循环到洋壳和上地幔中。大洋岛玄武岩 (OIB) 和大陆溢流玄武岩 (CFB) 大多显示出接近于零的 ΔHg 值，这表明下地幔中的表面汞循环有限。与电弧相关的和陆内热液系统中重熔的陆地物质的相反的 ΔHg 值凸显了使用汞同位素进行成矿示踪的巨大潜力。