Organic Geochemistry and Mineralogy Characterization of Cayirhan Oil Shales Associated with Element Enrichment, Beypazari, Ankara, Turkey

摘要

The concentrations of minerals and trace elements in the Cayirhan oil shale (COS) (Beypazari, Ankara, Turkey) have been determined by XRD and ICP-MS. Total organic carbon (TOC) content of COS samples were determined to have relatively high values (TOC 2.08%-23.29%, average 9.53%). Relative to the average shale, enrichment factors for COS indicated enrichment of the following elements: Mn, Mg, Pb, Si, Sr, Zr, K, Ca, Na, U, Ba, Cu, Ni, As, V, Co, Mo, Rb Fe, P, Ti, Sb and Cd. Element enrichments in sediments are the results of inputs from different sources and accumulate in different phases. Oil shale mineralogy plays a key role in determining elemental enrichment. As the organic matter content in rocks increases, it can result in enrichment of U, W, Hf, Ce, Ba, I, Sb, Cd, Mo, Rb, Se, As, Ge, Zn, Cu, Ni, Co, Cr and V. Samples of COS contain a range of different minerals including Albite, Alabandite, Ankerite, Analcime, Barite, Dolomite, Glauconite, Gypsum, Calcite, Clay Minerals, Clinoptilolite, Quartz, Kutnohorit, Magnesite, Marcasite, Microcline, Muscovite, Natrolite, Orthoclase, Pyrite, Pyrochlore, Raspit, Sanidine, Saponite , Sphalerite, Spinel, Talc, Titanomagnetite, Vermiculite and Zeolite. The depositional environment of COS led to enrichment of Mn in the form of Ankerite, Kutnohorite and Alabandite minerals; the enrichment of Mg in Dolomite, Ankerite, Magnesite, Spinel and Clay minerals; enrichment of Fe in ankerite, talc, sepiolite, glauconite, pyrite, nantronit, kutnohorit, titanomagnetite biotite minerals. The results provide a definitive chemical and mineralogical characterization of the oil shale and identify the major mineralogical origins of important trace elements.