Investigation of Organic Carbon and Iron Group Elements in Bituminous Rocks

In this study, geochemical and biogeochemical features of the organic-rich bituminous shales of the Bolu-Mengen area were investigated. The deposition levels of carbon and iron group metals (Mn, Ni, V, Cr, Co, Ti, Sc) within the bituminous shales and their correlation were also examined. Samples studied contain high amount of organic carbon (Corg), and they have Type I and Type II kerogenes that can generally produce oil and gas. Corg distribution in the samples was found as 0.55–0.99% for 5 samples, 1.23–1.96% for 9 samples, 2.31–3.95% for 5 samples and 4.12–19.14% for 15 samples. 75–100% of the organic material is determined to be amorphous and algal. Corg and metal contents of the bituminous shales in the area are characteristic with cyclic changes. Samples with high Corg values show high correlation with Fe group elements. The variations in cogenetic Corg and metal contents in samples are also discussed.

Keywords:

• bituminous shale
• kerogene
• organic carbon
• amorphous
• diagenesis
• element

Acknowledgments

We thank the Research Foundation of Ankara University for financial support of this work through Project 2001-07-05-062. The authors wish to thank two anonymous referees for their critical reviews. The authors also acknowledge geological engineer Burak Üzmez for helping at the field study.