Investigation of mineralogical, geochemical and genetical properties of bauxite ore in Fakılar village (Çamlıyayla-Mersin)

The study area covers Fakılar village and its surroundings, belonging to Çamlıyayla district of Mersin province, located in the south of the Bolkar Mountains in the eastern part of the Central Taurus Mountains. Triassic aged Dişdöken formation and Bajocian-Santonian (Jurasic-Cretaceous) Demirkazık formation are located at the base of the succession in the region. Gildirli, Kaplankaya and Karaisalı formations, consisting of Miocene aged coarse clastics, clay stones and carbonates, overlie this basement with an angular unconformity. The aim of this study is to examine the mineralogical, geochemical and originary properties of bauxite ore occurring in semi-regular-irregularly occurring (Jurasic-Cretaceous) limestone-dolimitic limestone units. Fakılar village bauxite ore is a karstic ore body with an irregular base topography showing macro-level piezolithic-oolithic structures, and mainly diaspore, hematite, kaolinite, illite, goethite, lepidocrosite, limonite and less commonly magnetite, which also shows stratified sedimentary structure in places. has a mineral paragenesis containing ilmenite, rutile, anatase, pyrite, calcite and quartz. Bauxite ore mainly consists of Al2O3 (49.36-63.82%), Fe2O3 (11.94- 27.43%), SiO2 (3.22- 9.99%) and AK (12.60-15.50%); In the second degree, TiO2 (1.69-2.90%) and small amounts of CaO (0.14-0.45%), MgO (0.10-0.30%), K2O (0.01-0.03%), P2O5 (0.04-0.08%), MnO (0.03-0.03%), Cr2O3 (0.03-0.06%) and Na2O (<0.01-0.01%) main oxide components. When the main oxide contents were normalized to Post-Archaean Australian Shales (PAAS), it was enriched in Al2O3, Fe2O3, TiO2, Cr2O3 and loss in fire (AK); It is observed that it becomes poorer in terms of Na2O, K2O, SiO2, MgO, total carbon (TOPC) and total sulfur (TOPS). In terms of correlation, strong positive correlations were observed between Al2O3-TiO2, CaO-SiO2, AK-MgO and CaO-MgO, moderate between TOPC-K2O and weak positive correlations between Al2O3-P2O5; There are strong negative correlations between SiO2-Cr2O3, Al2O3-Fe2O3, moderate correlations between CaO-Cr2O, P2O5-TOP, TOPC-Cr2O3, and weak negative correlations between Al2O3-K2O. Trace elements such as Nb, Ta, Zr, Th and U show good positive correlations with TiO2 and Al2O3, meaning that these elements are highly immobile during bauxidation. The average abundances of V, Zr, Pb, Zn and Ni elements, which have relatively high contents, are 388.83, 494.77, 494.77, 225.33 and 207.28 ppm, respectively. The average abundances of elements with lower contents such as Co, Ga, Sr, Th, Ba, Be, Hf, Nb, Sn, Ta, U, W, Y, Mo, Cu, Sb and Bi are 34.95, 68.63, 55.45, 71.18, respectively. , 32, 10.5, 13.78, 42.48, 12, 3, 11.13, 6.95, 61.70, 13.82, 16.73, 8.6, 4.05 and 31.77 ppm. According to PAAS-normalized trace element patterns, Sc, Pb, Zn, Ni, Ga, Nb, Nb, Sr, Ta, Th, U, Y, V and Zr elements are enriched, whereas Rb, Cu, Ba and Cs elements are depleted; Co exhibits an almost immobile behavior. According to the correlation coefficients, the elements are strongly positive with each other (Hf-Zr, Nb-Sn, V-As, Co-Ni); moderately positive (Ba-U); they show moderate negative (Ga-Cd, Nb- Zr,) and very weak negative (Y-Zn) correlation relationships. Total rare earth element (ΣREE La–Lu), light rare earth element (ΣLREE La–Eu) and heavy rare earth element (ΣHREE Gd–Lu) concentrations in the ore samples are 311–780 ppm (average 572 ppm) 270–722 ppm, respectively ( average 523 ppm) and 41–58 ppm (average 49 ppm). As a result of the normalization of the rare earth element contents of the samples taken from the field with the rare earth element contents of PAAS and chondrite, it was determined that heavy rare earth elements (HREE) enriched between 10 and 1000 times according to light rare earth elements (LREE), part according to PAAS and chondrite. Negative Eu (Eu/Eu*=0.66 Mean) anomalies of bauxite ores, possibly decomposition of calcium-rich plagioclases of the parent rock during weathering and transport of Eu element from the environment; positive Ce (Ce/Ce*=1.08 Mean) anomalies indicate that serianite (CeO2) mineral was formed in the weathering zone under oxidant ambient conditions or that it might have been enriched by the adsorption of Ce ions on the clay particles. Rare earth elements belonging to bauxite ore samples are strongly positive (La-Ce, Tm-Lu) and strongly positive (Ce-Sm, Eu-Yb); also very strongly positive among major, trace and rare earth elements (Al2O3-Sn, TiO2-Nb); strong positive and moderately strong positive (Al2O3-Zr, Al2O3-Sm, TiO2- Yb, Al2O3-Lu, TiO2- Nd, P2O5- TREE); strong negative (Al2O3-Ni, TiO2- Co), moderately negative (Fe2O3- Ga, SiO2- Th) and very weak negative (Fe2O3-TREE, SiO2- Zr, SiO2-TREE) correlation relationships are shown. Fakılar Village karstic bauxite ore is classified as ferrous bauxite and clayey bauxite according to the main and trace element contents. Origin studies based on geochemical data revealed that Fakılar Village bauxite ore was most likely formed by weathering-karstification, transport and redeposition and progressive weathering processes associated with a felsic-origin magmatic or sedimentary rock mass providing clastic material from the land during the deposition of carbonate rocks in which it is located understandable. Keywords: Fakılar Village, Çamlıyayla-Mersin, Bauxite, karstic, Diaspore, kaolinite, Göethite, Hematite, REE, origin