Abstract: Büyükbelen iron ore composed of autochthonous laterites and red soils. Thin (5-10 cm) hematitic and thick (5-15 m)goethitic layers were determined in the lateritic prophile. In the small karstic cavities (1 dm -7m diameters) within the weathering zone, semiautochthonous earthy limonites and colloform goethites were deposited.Structural and textural features of the ores are controlled essentially by goethite, siliceous components (quartz, opal-CT)and hematite. Hematites usually occur as euhedral crystals agregates, while the most of the goethites are seen as bouquets offine, fibrous crystals in the crusty and botiyoidal ore textures. Lateritic iron ore includes average 49.71 % Fe2O3, 30.75 %SiO2, 3.12 % Al2Oh 0.42 % K2O, 0.11% Na2O and 0.09 % Cat).The mineralogical compositions of the parent rock (chertspelagic limestone), laterite (hematitic and goethitic layers) andred soil samples are as follow. Chert: Quartz, calcite, opal - CT, hematite, amorphous matter; pelagic limestone: Calcite,quartz, opal-CT, illite, hematite, amorphous matter; the hematitic section of the laterite: hematite, ferrihydrite, quartz, opalCT, illite, kaolinite, amorphous matter;` the goethitic section of the laterite: Goethite, ferrihydrite, quartz, amorphous matter;red soil: Quartz, opal-CT, calcite, montmorillonite, illite, amorphous matter.Geological, mineralogical, structural and textural properties and geochemistry ofBüyükbelen iron ore point that iron hasbeen derived from Upper Cretaceous aged pelagic carbonates intercalated with chert around Büyükbelen. Ore forming lateritic and partly karstic processes were effective during the Plio-Quaternary period. Goethite occurrences were resulted fromweathering of iron bearing parent rock during the wet periods. Afterwards hematites were also formed as a result of the dehydratation of goethites.