Elements: Halogens: From Planetary Surfaces to Interiors

October 06, 2022

The halogen-­group elements (F, Cl, Br, and I) are common in the terrestrial inventory, though often present in trace amounts in many Earth and planetary materials. The halogens play a key role in a variety of geologic environments and processes, from mineralization to their influence on the composition of Earth's atmosphere when released as oceanic, volcanogenic, and anthropogenic emissions. Halogens act as "fingerprints" of fluid­mediated processes on Earth and other planetary bodies. These "bioessential" elements are also critically important to human health. In this issue of Elements, we explore the role that the halogens play in shaping diverse planetary systems, from the surface of planets to their interiors. We also review the techniques that are suitable for the analysis of halogen elements and of isotopes of Cl and Br in terrestrial and extraterrestrial materials.

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