Rare Earth and Critical Elements in Ore Deposits

It has often been said that the only thing that remains constant in the world of natural resource commodities is change -and this was especially true in the first decades of our new century, which saw sudden and often unpredicted interest in a range of unfamiliar minor commodities.This new Reviews Series volume, Rare Earth and Critical Elements in Ore Deposits, from the Society of Economic Geologists provides a timely review of the geology and mineralogy of a diverse group of minor elements that are now commonly termed the critical minerals or critical elements.In this context, criticality means at least two things -first, many of these commodities are vital in modern technology, particularly in clean and efficient energy generation, but also in computers and communications.The omnipresent iPhone, and all other such devices, depend on at least 20 of these little-known and rare elements.Secondly, many of these elements are equally critical in another sense, as major reserves and most production are geographically focused in countries not noted for their stability, or for political agendas closely aligned with those of western industrial consumer nations.For some elements, for example tantalum (Ta), ethical concerns have been expressed about the use of resource revenues to fuel long-lived conflicts involving human rights violations.Despite the wide perception of some of these elements as 'green' commodities, many comments have also been made concerning the environmental impacts and carbon footprints associated with their extraction and processing.In short, nothing is simple when it comes to critical minerals, and their geology is no exception.This excellent volume is a response to the need for better technical information, prompted by increased exploration to identify new sources.Much of this effort has been corporate, tempted by the prospect of strong returns on investment, but many governments also have a strong interest in reducing reliance on outside sources and their associated political-economic risks.Given this framework, it is not surprising that the United States Geological Survey (USGS) is an important supporter of this publication, which is in part a valuable outgrowth of their own work to document domestic REE resources.The fourteen chapters, each framed as an independent paper with an abstract summary and full bibliography, review known deposits and metallogenic environments largely