First Information about Rare Earth Mineralization in Rocks of Esmeralda Volcano (Mariana Island ARC)

The article presents the results of a study of rare earth mineralization in the rocks that make up the Esmeralda underwater volcano, located in the southern part of the Mariana island arc. Despite the fact that the composition and structure of the Esmeralda volcano have been studied by various scientists for 75 years, information about the content of rare earth elements in its rocks is sporadic and is given in only six studies, and in two of them, only average values are presented. Our microlevel study of the mineral composition of basaltic andesite dissected by a crack, dredged during the fifth cruise of the R/V Vulkanolog in 1978, made it possible for the first time for the Esmeralda volcano to establish the presence of rare earth minerals in its rocks and to determine their composition and formation conditions. It has been established that minerals are localized in free intracrack zones and gas vacuoles.