Rare Earth Elements in Ultramafic and Mafic Rocks and their Minerals: Main Types of Rocks. Rock-forming Minerals

Abstract

Nowadays lanthanides or rare earths are recognized as a group of elements of the periodic table with unique chemical properties and extremely important for science. Although these elements were discovered long ago and their chemistry is well studied, their application in geology was made difficult due to their extremely low concentrations in most natural media and to difficulties in obtaining correct data on their contents in particular samples. In the latter half of last century these difficulties were overcome mostly due to the development and introduction of new devices and methods which provided a rather high level of sensibility and precision for determining the low concentrations of rare earth elements (REE) not only in rocks but in individual mineral crystals as well. At present, REE are widely used for solving many geological problems, including reconstructions of the geochemical evolution of the Earth and other planets of the solar system.