Geochemistry of Rare Earth Elements in Pahang River Sediment, Malaysia

Abstract

Rare earth elements (REE) are a set of 17 chemically similar metallic elements including 15 lanthanides, scandium and yttrium. The current status of REE as aglobalstrategic commodity has encouraged the identification of REE ore deposits. This research is carried out to identify the mining feasibility of fluvial sediment REE and to understand the sediment'sphysical and chemical characteristics and effects on the geochemical behaviour of REE in the longest river of Peninsular Malaysia namely Pahang River. Surface sediment samples were collected along Pahang River (n=44) in approximately 10 km distance intervals. The sediment samples were analyzed using XRF to determine the major oxide content. Meanwhile, REE content in the sediment samples wasextracted using the Total Digestion method and analysed using ICP-MS. The results show the average valueof ΣREE at surface sediments of the Pahang Riveris42.58ppm and can be considered too low to be economically mined. Each area shows higher fractionation of light REE than heavy REE with negative europium anomalies, suggesting sediments in this area werederived from felsic rocks. The concentration of REE in Pahang River surface sediments wascontrolled by the porosity and organic matter as showed by the correlation of ΣREE with porosity (R2=0.65) and organic matter content (R2=0.71). In conclusion, this research's findingsare generally useful for further REE mineral exploration and fluvial sediment environmental monitoring.