Constraints on unconsolidated pyroclastic flow sediments related REE enrichments originated from potassic-alkaline Gölcük stratovolcano: Darıdere-Direkli-Yakaören (DDY) table 4deposits, southwestern Anatolia of Turkey

Abstract

In the last five decades, Rare Earth Elements (REE) are mostly produced from carbonatite complexes and alkaline magmatic environments. In this respect, pyroclastic flows produced by the potassic-alkaline Golcuk volcanism in the Isparta (SW, Turkey) angle stand out as an important target area where REE enrichments can be observed. This study focuses on the REE potential, geochemical and mineralogical characteristics of REE-bearing minerals as well as formation modeling of unconsolidated pyroclastic flows in Daridere-Direkli-Yakaoren (DDY) deposits in Turkey. REE-bearing minerals of DDY deposits which contain abundant trachytic-trachyandesitic rock fragments were determined as fluorapatite, britholite, and chevkinite by using XRD and SEM–EDX analyses. According to the geochemical analysis, the vast majority of ΣREE (up to 996 ppm) content is LREE such as La, Ce and Nd. Daridere is the most REE enriched region followed by Yakaoren and Direkli regions in terms of LREE (574.9 ppm), relative to MREE (38.5 ppm) and HREE (5.28 ppm) contents. These results are also on par with subduction-related Italian extrusive carbonatites such as Polino, Cupaello and San Venenzo. The DDY deposits can also be comparable with intraplate extrusive REE deposits in terms of LREE enrichments, however, HREE, Nb, Th and Zr values are generally lower. The ΣREE concentrations tend to rise with the increasing contents of alkaline elements (Na and K), HFSE (such as Nb and U), as well as LILE (Ba, Sr and Rb) and are negatively affected by sedimentary carbonate involvement. The economic value of the DDY deposits can gain importance due to the increasing global demand for LREE’s.