February 2024 – Volume 20 Number 1
GUEST EDITORS
Mehmet Yesiltas and Yoko Kebukawa
PRINCIPAL EDITOR
Sumit Chakraborty
April 2024 – Volume 20 Number 2
GUEST EDITORS
Simon R. Wallis, Kazuhiro Miyazaki, and Ulrich Knittel
PRINCIPAL EDITOR
Becky Lange
June 2024 – Volume 20 Number 3
Extraterrestrial organic matter is found in various extraterrestrial environments and in various forms. It forms in a variety of locations through different mechanisms in space. As such, its nature, distribution, formation mechanisms and locations are of particular interest. Some organic molecules are even considered as key players for the emergence of life on Earth and possibly beyond. Therefore, their detection and characterization can contribute to the understanding of the early solar system evolution as well as the origin of life. Despite decades of work and research, there are still many questions and unknowns on this topic. The aim of this issue of Elements is to offer an overview of the concept of extraterrestrial organic matter as well as the latest scientific findings.
Subduction, where one plate dives beneath another, controls longterm wholeEarth cycling of rocks, fluids, and energy. Plates subduct faster than they heat up, making them the coldest parts of the Earth’s interior. Fluids released from these cold plates rise into hotter overlying rocks, forming magma that feeds surface volcanism. Cold deep conditions associated with subduction complemented by hot shallow conditions under volcanic arcs are reflected in the presence of pairs of metamorphic belts, representing sites of ancient subduction. This issue of Elements guides readers through a premier example of paired metamorphism: the Cretaceous SanbagawaRyoke metamorphic pair of Japan. Estimates of pressure, temperature, the age and duration of metamorphism, and the tectonic framework in which meta morphism took place help us to develop quantitative models—both for the evolution of SW Japan and subduction systems in general.