v18n6 From the Editors
By Richard Harrison, Becky Lange, Janne Blichert-Toft, and Esther Posner | December, 2022
Io is the best place to understand a fundamental process that shaped terrestrial planets, icy ocean worlds, and extrasolar planets: tidal heating. Caught in orbital resonance with other Jupiter moons (Europa and Ganymede), Io is the most tidally heated world and may contain the only extant magma ocean in our Solar System. The spectacular volcanic plumes sustain the atmosphere and feed the magnetosphere of the Jovian system. The hot lavas on its surface reflect heat pipe tectonics, which is analogous to the volcanically hyperactive youth of all rocky planets. Io is the ideal planetscale laboratory to study the intertwined processes of tidal forcing, extreme volcanism, and atmospheremagnetosphere inter actions. Investigating Io is necessary to understand ocean worlds, tidallyheated exoplanets, and the early terrestrial planets, including how they evolve chemically.
This issue of Elements reviews our knowledge of Io, including discoveries from telescopic obser vations, past missions, as well as perspectives for future missions. Six chapters cover interior dynamics and surface processes, with insights from field and laboratory studies in volcanology, petrology, geochemistry, and geophysics.
v18n5 From the Editors
By Richard Harrison, Becky Lange, Janne Blichert-Toft, Martha Evonuk, and Esther Posner | October, 2022
Cement and concrete are essential commodities for a steadily growing and urbanizing world population. Availability, affordability, versatility, and durability have made cement and concrete the second most used material by mankind, behind water. However, their production leaves a large environmental footprint in terms of CO2 emissions (about 8% of all anthropogenic emissions are associated with the production of cement) as well as depletion of mineral and water resources. Making cement and concrete more sustainable and resilient represents a formidable societal challenge that mineralogists and geochemists can help resolve.
This issue looks back into the history of cementitious materials from antiquity to the Portland cements used today. Alternatives to Portland cement are explored and options for sustainable sourcing of raw materials are discussed in local and even extraterrestrial contexts. Moreover, this issue highlights how mineralogy, geochemistry, and petrography can be applied to assess resources, characterize and develop a new generation of cement and concrete, and understand how basic physical and chemical processes occurring at the microscale affect macroscopic material properties.
v18n4 From the Editors
By Richard Harrison, Becky Lange, Janne Blichert-Toft, Esther Posner, and Jodi Rosso | August, 2022
Subduction zones—some of the most active geological regions on Earth—are also home to dynamic landscapes and destructive geological events. The Cascadia subduction zone (also known as Cascadia) runs along much of the western margin of North America and occupies an influential place in the global pantheon of subduction zones. Cascadia is known as the quint essential “hot and dry” endmember of subduction zones produced by the subduction of relatively young oceanic crust, and studies of Cascadia have enriched our global understanding of subduction, continent assembly, and many related geodynamic processes.
In addition, the link between tectonic processes and geological hazards is made crystal clear via a raft of wellrecognized volcanic, earthquake, tsunami, and other geologic hazards, emphasized by high-profile events such as the eruptions of Mount St. Helens, as well as an uneasy anticipation of future great earthquakes and tsunamis.
This issue of Elements takes a detailed look at the Cascadia subduction zone—not only from the perspective of the geological and geophysical processes that have produced this canonical continental subduction system but also considering the impact of active subduction processes and landscapes on the people and societies who have long inhabited the region.
v18n3 From the Editors
By Richard Harrison, Becky Lange, Janne Blichert-Toft, Esther Posner, and Jodi Rosso | June, 2022
At first glance, the presence of water may appear as a very earthy characteristic. However, observations of the Universe and Solar System have revealed a very different reality where water molecules are omnipresent in liquid, gaseous, or solid form. From cold molecular clouds to magma oceans and the young Solar System, water is a major constituent and player in astrophysical and geo logical processes. Within our Solar System, water has been found to occur and react in asteroidal, lunar, and planetary environments. In fact, most water molecules have borne witness to the Solar System’s formation and evolution over the past 4.5 billion years.
This issue of Elements details the diversity of environments and processes where water is present and involved, offering a journey through space and time seen through the spec trum of this fundamental mole
v18n2 From the Editors
By Richard Harrison, Becky Lange, Janne Blichert-Toft, Esther Posner, and Jodi Rosso | April, 2022
Life on Earth produces innumerable structurally diverse biomolecules that are ubiquitous in the environment. Such organic compounds are diagnostic indicators of biotic and abiotic processes in water, soils, sediments, sedimentary rocks, petroleum systems, and mineral deposits.
In this thematic issue, the authors introduce applications of biomarkers to study fundamental biogeochemical processes and the utilization of organic molecules and their compoundspecific isotope signatures as proxies for paleoenvironmental and climate reconstructions. Organic geochemists also search for molecular signatures to study life evolution and early Earth history, life in extreme environments such as hydro thermal systems and the deepcrustal biosphere, and to detect extraterrestrial life forms on other planets.
v18n1 From the Editors
By Richard Harrison, Becky Lange, Janne Blichert-Toft, Esther Posner and Jodi J. Rosso | February, 2022
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.