Rare earth elements (REEs) investigation of fly ash placers in southwestern Taurides: footprints of alkaline potassic Gölcük volcanism, Turkey

The importance of Rare Earth Elements (REE) is consistently rising for industrialized countries due to their widespread usage in various applications. Production of REE heavily relies on carbonatite-ijolite complexes and other alkaline magmatic products. With this perspective, the potassic-alkaline volcanism related fly ash placers in Burdur and Isparta regions (SW, Turkey) are considered as a valuable prospecting target for REE. This work primarily focuses on the REE enrichment features (geochemistry, mineralogy, provenance and alteration processes) of Burdur and Isparta fly ash placers for construing the REE behaviour. At last, formation modeling of studied deposits was established and the similarities between studied deposits and some World class REE deposits were presented. Main REE-bearing minerals of studied deposits were identified as chevkinite, britholite and fluorapatite with considerable amounts of LREE as well as Th, Fe and Ti. The geochemical analysis results show that most of ΣREE values (up to 1109 and 1233 ppm, respectively) were comprised by La, Ce, Nd and Pr elements. The smaller grain size is a key factor in REE enrichment by the effect of combined factors such as REE-bearing mineral’s average crystal size, distribution, and higher intensity weathering process. The interference of Ca from meta-sedimentary carbonate rocks have a negative effect on REE accumulation. Because of the good response for ore purification methods and promising results for some of the critical REE, Burdur and Isparta fly ash placers might be feasible in the future in case of tighter supply and increasing global demand.