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    Rare earth element (REE) resources of Turkey: An overview of their characteristics and origin
    (Maden Tetkik Ve Arama Genel Mudurlugu-Mta, 2019) Ozturk, Huseyin; Hanilci, Nurullah; Altuncu, Sinan; Kasapci, Cem
    The Rare Earth Elements (REE) deposits and mineralization of Turkey can be divided into four types based on their geological setting and origin. First are deposits associated with carbonatite-alkaline magmatic rocks, rich in Light Rare Earth Elements (LREE). The bast known examples are the Kizilcaoren (Eskisehir) and Kuluncak (Malatya) deposits with TREE grades of 2.9% and 0.7% respectively, and typical enrichment of La-Ce. Lower grade REE mineralization at Keban (0.05% TREE) and Divrigi (0.13% TREE) is associated with abundant fluorite and all four occurrences show similar ranges for homogenization temperatures and salinities for fluid inclusions in fluorite and REE profiles. The second type are Triassic shales and the bauxites formed from them in the Bolkardagi region. Enrichment of Heavy REE (HREE) is typical and TREE grades are about 0.15% in bauxites and its protolith. These occurrences are geochemically similar to ion adsorption type deposits associated with lateritic clay on the weathered granitic rocks of China. Third is the placer type, represented by the canakli (Burdur) deposit which is enriched in U, Th and HREE and heavy minerals such as; magnetite, zircon and rutile and has an average grade of about 0.08% TREE. The fourth potential source of REE is phosphorites. These rocks host the world's largest resources elsewhere, however the Cretaceous Mazidag deposits in Turkey are very low grade (40ppm TREE) and clearly uneconomic. Consideration of the environmental and health issues associated with exploitation and processing of REE has identified the more favorable outcomes associated with exploitation of the ion adsorption type of deposits and justification for further evaluation of the resources and processing technologies that would enable exploitation of REE-enriched bauxites in the Bolkardagi region.
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    Rare earth element-bearing fluorite deposits of Turkey: An overview
    (Elsevier, 2019) Orturk, Huseyin; Altuncu, Sinan; Hanilci, Nurullah; Kasapci, Cem; Goodenough, Kathryn M.
    Rare Earth Element (REE)-bearing fluorite deposits in Turkey occur in association with Cenozoic post-collisional alkaline-carbonatite systems and can be divided into three groups: (1) carbonatite-associated; (2) those associated with subalkaline to alkaline magmatic rocks of Cretaceous to Cenozoic age; and (3) those in sedimentary successions, typically in areas dominated by limestone. Some of these deposits show significant enrichment in the REE, especially the Kizilcaoren deposit which has average REE grades of almost 30,000 ppm; others have very low REE contents but have potential fluorite resources. The homogenization temperature and salinity values of fluid inclusions in these deposits vary between 600 degrees C and 150 degrees C, and 10-65 wt% NaCl eq., respectively. The carbonatite-associated deposits have the highest bulk REE contents and are LREE-enriched. As a general feature, the REE contents of the fluorite deposits decrease with decreasing homogenization temperatures and salinity of the fluorite fluid inclusions. Fluorite ore chemistry indicates that a plot of Nb + Ta versus total REE differentiates the carbonatite- hosted from the alkali intrusive hosted and carbonate- hosted deposits. Beyond the cooling and/or dilution of the fluids, REE and fluorite deposition was driven by changes in pH, instead of change in Eh, according to our geostatistical treatment. The chondrite-normalized rare earth element patterns of each group of deposits show some similar features, indicating that the REE in the fluorite are independent of their host lithology, but reflect the magmatic systems from which they were derived. Overall, the F-REE deposits of the Anatolides-Taurides in Turkey are considered to be largely related to the post-collisional magmatic systems, but with variable contributions of fluids from other sources.