February 2016 - Earth Sciences for Cultural Heritage
Volcanoes are the powerhouses of nature that can, within minutes, transform a beautiful mountainscape into a desolate landscape devoid of life. Whether eruptions are mild or catastrophic, volcanoes fascinate and captivate us. But what controls whether a given magma will erupt or stall, and how do processes in one part of the system affect others? Volcano science is advancing rapidly, and improvements in monitoring tools, petrologic tools, and modeling of volcanic processes have greatly improved our understanding of volcanic behavior. This issue brings together contributions exploring volcanic behavior throughout the crustal system.
April 2016 - Enigmatic Relationship Between Silicic Volcanic and Plutonic Rocks
Despite the bulk silicate Earth only containing 250 parts per million of sulfur, sulfide minerals and liquids have a powerful impact on the behavior and fractionation of a wide range of elements in the Earth’s crust and underlying mantle. This issue focuses on the broad topics of magmatic and volcanogenic sulfide deposits, the behavior of sulfides during mantle melting and volcanism, and the mineralogy of sulfides and sedimentary sulfides and their role in the early development of the biosphere.
Coatings result from the wide variety of reactions and/or processes that occur at the interface between the lithosphere and the biosphere, hydrosphere, and atmosphere. Such coatings are biochemically, mineralogically, and isotopically complex and have the potential to record changes in their immediate environment. The transition between a coating and its underlying host is abrupt and defined by a sharp interface at the nanoscale. Articles in this issue highlight new and exciting research in the field of coatings, focusing on coatings formed in deserts, soils, sediments, oceans, and on rocks from Mars.
Fifth in the periodic table, boron is a “light” element whose origin has puzzled astronomers because it is not created in stars. It is “lively”, being an essential element for plants, and having medicinal properties, which has stimulated synthesis of organic compounds containing boron. Borates such as colemanite are thought by some to have stabilized ribose, an essential component of ribonucleic acid and critical for the self-assembly of prebiotic organic compounds to constitute life; others have proposed that ribose was stabilized by borate in solution. Boron isotopes provide insight on the processes responsible for the creation of continental crust, and act as a proxy for paleoclimate. Extreme concentrations of boron result in economic evaporitic deposits, and, thus, water-soluble boron minerals, notably borax, have been among the most accessible of useful compounds to humankind, even in antiquity.
Mineral resources are a vital part of any economy, modern or ancient. Since the birth of civilization, man has used these resources for pigments, metals, glasses, ceramics, cements and much more. The media has recently suggested there is a crisis looming over finding mineral resources, including critical metals. Centered on the sustainability of mineral resources, themes addressed in this issue include customer–supplier relationships, exploration, recycling and the circular economy, and environmental post-mining impacts. The broad range of topics embraced by this issue – formation of mineral deposits, minerals engineering, and environmental and societal impacts – will provide readers a better understanding of the large-scale economic, historical and educational aspects of mineral resources.
For more than 50 years, layered mafic-ultramafic intrusions have served as natural laboratories for studying magma chamber processes and magmatic differentiation. Further enhancing our understanding of layered intrusion formation will yield valuable insights into the solidification of magmatic systems, the formation of precious metal deposits, and the timescales over which substantial crust-forming episodes occur. This issue of Elements offers an overview of the current state-of-the art in the petrology of layered intrusions and a looks forward to the future challenges in the field.