From the Editors

In this issue, we follow the halogen group elements (fluorine, chlorine, bromine, and iodine) from the Earth’s interior to surface—and even beyond! In a similar vein to two previous Elements issues that also explored groups of elements united by common properties (Rare Earth Elements; October 2012 and Platinum Group Elements; August 2008), this issue similarly showcases the wide diversity of research that is encompassed by halogen mineralogy and geochemistry. Over the last several decades, the halogens have increasingly come into the spotlight, possibly due to improving methods for measuring ultra-low abundance bromine and iodine in geologic materials, as well as isotopes of chlorine and bromine. The result of this increased enthusiasm for halogens is deftly covered over six articles by this issue’s authors—from halogens in Earth and planetary systems to experimental petrology and analytical developments, there truly is something for everyone.

There are many individuals and organizations who we want to recognize for their participation in and support of Elements in 2021.

Elements is published through the collaboration of 18 participating scientific societies. The Elements editorial team is responsible for the content and the day-to-day management of the magazine. The Elements Executive Committee is responsible for the management of the magazine through financial oversight, approval of editorial appointments, and facilitating a close working relationship between the editorial team and the participating societies.

For centuries, philosophers and scientists had proposed the existence of planets outside of our own Solar System. Yet, it wasn’t until late 20th century that scientists first confirmed the existence of exoplanets. How does one study planets that are thousands of light years away from Earth? Exoplanet studies are not purely within the domain of astrophysicists. As you will discover in the articles of this issue, exoplanet research requires an interdisciplinary approach.

In just about every physical science course the concept of the atom is taught. Students are introduced to the three subatomic particles of electrons, protons, and neutrons. Usually, there is a lot of emphasis on electrons, because their configuration determines the chemical properties of an atom. And the protons get a lot of attention as well: who doesn’t like H+? Sadly, too often, neutrons are left in the “Oh, there is another part of an atom” category … that neutral subatomic particle that adds weight to the atom.

Science is a breeding ground for jargon. Jargon is useful and elegant for the specialist but often a conundrum for the nonspecialist. As you read the articles of this issue of Elements, you will likely encounter some of this rich terminology, including the evocative terms “snottite” and “moonmilk”. But, thankfully, the editors and authors have made considerable effort to translate much of this cave science jargon so that we, too, can enjoy the wonderful world of speleothems.

This issue on the European Alps is the third geographic region showcased in Elements. If you are interested in reading about other geographic regions, we encourage you to check out the Elements issues on the Central Andes (August 2018) and the South Aegean Volcanic Arc (June 2019).

As part of every years’ final “From the Editors”, we like to thank the many people who have contributed to Elements over the course of the previous year. But before we do so, we want to acknowledge that 2020 was a year unlike any other in the history of Elements. The global pandemic impacted all of us in profound and, for many, sometimes tragic ways. The challenges that our readers, editors, authors, participating societies, and advertisers faced in 2020 makes it even more meaningful to thank our contributors. We greatly appreciate all your efforts!

Marissa Tremblay, Emily Cooperdock, and Peter Zeitler, guest editors of this issue of Elements, introduce us to another application of noble gases: thermochronology. In addition to editing the six thematic articles on the utility of noble gas thermochronology to fundamental geological questions (e.g., What are the rates of exhumation? How does a fault zone evolve?), these guest editors also wrote this issue’s Toolkit, which introduces the different methods used to extract, isolate, and measure the concentration of noble gases (and their isotopes) derived from natural materials. We hope you enjoy reading about this fascinating topic!

Elements magazine has published many topical issues for which the focus has been on an individual element (see graphic). Some elements were featured as a group, such as the platinum group elements (v4n4) or the rare earth elements (v8n5). Others were featured as allotropes, as happened for carbon as diamond (v1n2) or carbon as graphite (v10n6). Yet others were featured in the context of an overview of the many roles that an element plays in natural systems. The current issue, “Lithium: Less is More” (v16n4), falls under this latter category.