Palynology is the microscopic study of fossil spores and pollens. Because plants evolved through time, and climates changed through time, the plants in coal-forming wetlands changed through time. In many coal basins, groups of coals, and sometimes individual coals, can be correlated based on their spore and pollen content. Vertical and lateral changes in palynology are sometimes good indicators of likely changes in coal quality because they relate to the original coal-forming swamp plants and swamp conditions. Palynology can be used to determine what the ancient coal-forming wetlands that formed the coal looked like for comparison to modern peat-forming wetlands.
Palynological analysis of coal and associated rocks is done by separating microscopic fossil spores and pollen from their rock matrix. This is done by dissolving the surrounding coal and rock in strong acids. Fossil spores and pollen are insoluable in acid and can be recovered from the residue of the acid treatment. Next, part of the residue is transferred to a microscopic slide, and examined under transmitted light at the microscope.
Hundreds of different fossil spores and pollens have been identified in the coal-bearing rocks of Kentucky. These are some examples (scale in microns. A) Lycospora granulata (produced by the lycopod tree Lepidophloios hallii). B) Crassispora kosankei (produced by the lycopod trees Diaphorodendron and Synchysidendron). C) Densosporites sphaerotriangularis (produced by Omphalophloios, a small (sub-arborescent) lycopod). D) Radiizonates difformis (produced by Omphalophloios, a small (sub-arborescent) lycopod), E) Punctatisporites minutus (produced by Psaronius tree ferns). F) Torispora securis (produced by Psaronius tree ferns). G) Deltoidospora levis (produced by small ferns). H) Microreticulatisporites sulcatus (produced by small ferns). I) Calamospora hartungiana (produced by reed-like calamites). J) Laevigatosporites minor (produced by calamites). K) Florinites mediapudens (produced by cordaites trees). L) Florinites florini (produced by cordaites trees) (Photographs by Cortland Eble).
- To learn more about coal composition go to What’s in coal?
If you have specific questions about this analysis, please contact Cortland Eble.