Magnetic Susceptibility and Europium Content of Terrestrial and Aquatic Materials in Volcanic Region as Proxy Indicator of Environment Change and Clue of REE Exploration

Europium (Eu) is one of the Rare Earth Elements (REE) that is easy to measure using instruments such as X-Ray fluorescence (XRF). Almost all natural materials from various depositional environments show minute Eu content ranging from 0.0 to 0.7 Wt%. Although the Eu content is very small, its presence indicates the coefficient correlation with the materials magnetic susceptibility. This research focuses on Eu content and magnetic susceptibility correlation of materials in various depositional environments in the volcanic region of Indonesia to be used as a proxy for REE presence in nature. Magnetic susceptibility and Eu content correlation are very diverse in various depositional environments, but most show a correlation of R~-0.5, although in certain environments, it shows a positive correlation up to R~0.7. The correlation does not show a certain pattern in the aquatic or terrestrial environment due to the natural bonds of Eu which can be in the form of EuO (ferromagnetic), Eu2O3 (paramagnetic) and Eu3O4 (antiferromagnetic) which are controlled by environmental changes and the abundance of Eu can be the clue of REE exploration.