Each of the halogens constrains a different aspect of volatile cycling in the solid Earth. F is moderately incompatible in the mantle and has a low mobility at Earth's surface, meaning that it is preferentially retained in the mantle and continental crust. In contrast, Cl, Br, and I are strongly incompatible and highly soluble. Chloride is the dominant anion in seawater and many geofluids and a major component of evaporite minerals. Br and I are essential for life and significantly incorporated into organic matter that accumulates in marine sediments. Surficial fluids circulated into continental and oceanic crust incorporate surface-derived halogens into alteration minerals. As a result, subducting slabs and arc lavas are weakly enriched in F and strongly enriched in Cl, Br, and I. Subduction has maintained mantle Cl and Br concentrations at relatively constant levels since Earth's early differentiation, but mantle I/Cl has decreased over time. ▪Halogen abundances on the early Earth were affected by I partitioning into Earth's core and possible loss of hydrophilic Cl, Br, and I in an early formed ocean.▪Halogens are powerful tracers of subduction zone processes on the modern Earth, with Cl, Br, and I having a dominantly subducted origin in Earth's mantle.▪The deep subduction cycles of Cl, Br, and I are more similar to that of H2O than they are to F, but the geochemical cycle of each halogen differs in detail.▪Halogen abundance ratios and stable isotope ratios vary systematically in Earth's surface reservoirs, meaning that halogens are powerful tracers of geological fluids and melts.

中文翻译：

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固体地球中的卤素循环


每种卤素都限制固体地球中挥发性循环的不同方面。 F在地幔中具有中等不相容性，并且在地球表面具有较低的流动性，这意味着它优先保留在地幔和大陆地壳中。相比之下，Cl、Br 和 I 是极不相容且高度可溶的。氯离子是海水和许多地质流体中的主要阴离子，也是蒸发岩矿物的主要成分。 Br 和 I 对生命至关重要，并且大量融入海洋沉积物中积累的有机物中。循环到大陆和海洋地壳的地表流体将表面衍生的卤素纳入蚀变矿物中。因此，俯冲板片和弧熔岩中 F 含量较弱，而 Cl、Br 和 I 含量较丰富。自地球早期分异以来，俯冲板块和弧熔岩使地幔 Cl 和 Br 浓度保持在相对恒定的水平，但地幔 I/Cl 浓度在时间。 ▪早期地球上的卤素丰度受到 I 分配到地核以及早期形成的海洋中亲水性 Cl、Br 和 I 可能丧失的影响。▪卤素是现代地球俯冲带过程的强大示踪剂，其中 Cl、Br 、I 的俯冲起源主要来自地幔。▪Cl、Br 和 I 的深俯冲旋回与 H2O 的旋回比与 F 更相似，但每种卤素的地球化学旋回在细节上有所不同。▪卤素地球表面储层中的丰度比和稳定同位素比有系统地变化，这意味着卤素是地质流体和熔体的强大示踪剂。