Lignites from the Plains region of Alberta, Canada—Part 1: Petrography and depositional environment.

The petrography of two coal seams in Alberta was determined using reflected light microscopy. Random reflectance is 0.36%, indicating a lignite rank. Huminite is dominant over liptinite and inertinite. Maceral assemblage suggests a wet forest moor depositional paleoenvironment. The predominance of telohuminite and gelohuminite over detrohuminite and inertodetrinite reveals peat formation in a rather reducing environment and a rapid burial of the peat, which prevented any significant oxidation. A few intervals with high levels of oxyfusinite reveal periodic drops of the water table. Results coincide with the interpretation based on the Na/K ratio, which is used as an indicator of the rate of sedimentation. [ABSTRACT FROM PUBLISHER]