Petrographical and geochemical characterization of sub-bituminous coals from mines in the Cesar-Ranchería Basin, Colombia

Petrographically, the La Jagua and Calenturitas coals are dominated by vitrinite, with low to high amounts of inertinite and low to moderate amounts of liptinite. The detailed petrographic data indicate a predominantly herbaceous plant input and oxidative conditions during deposition, mostly with strong tissue destruction. Further conclusions are deduced from petrographic ratios such as tissue preservation-, gelification-, groundwaterAC- and vegetation indices, ash- and sulfur contents, iso- and n-alkane distribution, and 17α(H)-homohopane ratio. In summary, the data support a formation in tropical, ombrogenic, rather wet peats with high bacterial activity.