The geology, mineralogy, characterization and utilization of nodular sepiolite (meerschaum) of Türkmentokat-Karatepe district (Eskişehir)

SUMMARYThe Geology, Mineralogy, Characterization and Utilization of Nodular Sepiolite (Meerschaum) of Türkmentokat-Karatepe District (Eskişehir)In this study; the geology, mineralogy and characterization of nodular sepiolite (also known as meerschaum) between the Türkmentokat and Karatepe villages (Eskişehir), which is called as Sarısu deposits, were done and the utilization of the meerschaum was studied. Because of its unique properties, such as adsorption chemical composition, white color, good porosity, low specific gravity and catalytic properties, meerschaum has many industrial applications. The most common usage of Eskişehir?s meerschaum is pipemaking. Small quantities have been used for other purposes, such as decoration (bracelets and necklaces), removing stains, and as thermal insulating material.The studied area is located in the east of Miocene aged Eskişehir basin. The meerschaum was occured as nodules and pebbles in very poorly sorted İmişehir Conglomerates which is composed of pebbles and cobbles of altered ultramafic rocks, magnesite and sepiolite. These beds are directly underlain by the ophiolite complex of Türkmentokat?s ophiolitic melange. On the basis of field investigations and laboratory studies, it is concluded that the nodular sepiolites (meerschaum) was probably formed in relatively shallow water under alkaline conditions, as a result of the in-situ replacement of magnesite (and/or serpantine?) gravels as stated by many researchers.XRD data indicates that sepiolite is the main mineral of the both samples of relatively pure nodular sepiolites (S1 and S3), while dolomite was identified in the other two samples (S3 and S4) as the accessory non clay mineral.The SiO2 and MgO were the two dominant oxides detected mostly within the samples of pure nodular sepiolites (S1 and S3) with respect to the chemical analysis done by XRF methods. On the other hand, in addition to SiO2 and MgO percentages, considerable percentages of CaO was determined in the other two samples, indicating dolomite contamination within the samples (S3 and S4).The SEM photomicrographs of four meerschaum samples showed distinctive fibrous morphology. The SEM images of dolomite-bearing meerschaum samples displayed dolomite crystals within fibrous texture. Both the SEM images and XRD data of the samples show relatively well-crystallized meerschaum.According to the BET analysis, the samples of the pure meerschaums (S1 and S3) had about 30 to 40 m2/g more specific surface area than the dolomite-bearing meerschaum samples (S3 and S4), indicating relatively better adsorption capacity of the formers than that of latters.On the basis of XRD, XRF, SEM, BET and thermal analysis, the raw meerschaums occurred within İmişehir Conglomerates as nodules and pebbles between Türkmentokat and Karatepe villages (known as Sarısu Quarries) can be classified as `right meerschaum? which indicates the best quality meerschaum as well as semi precious stone.Key Words: Meerschaum, Nodular Sepiolite, Eskisehir (Turkey)