Ion adsorption-type rare earth element deposits in western Peninsular Malaysia: A case study in Bukit Enggang Granite, Kedah

Abstract

This paper reports on the rare earth element (REE) deposit in Bukit Enggang Granite in Sik, Kedah, and its enrichment patterns. The granitic rock in the study area is porphyritic biotite granite with K-feldspar, quartz and biotite as the main minerals, with randomly arranged K-feldspar phenocrysts. The average REE content in rock samples is 340.9 ppm. The exposed weathered profiles are between 3 to 7 meters in thickness. The C horizon is thicker than the B horizon. The average REE content in soil samples taken from the weathered profiles is 943.9 ppm. Interpretations from laboratory results reveal that the REE deposit in the study area is of the ion adsorption-type, with the REE enrichment in the weathered profiles originating from easily weathered REE bearing minerals in the parent rock, rather than highly resistant minerals like monazite, xenotime and zircon.