BGS Rock Classification Scheme
Cannel-coal - A type of sapropelic-coal. It is a dull black, has a waxy lustre, is homogeneous, has concoidal fracture, and is rich in miospores with very little alginite. Macroscopic examination shows no stratification. Microscopic examination shows that compared with humic coals the macerals are more intimately mixed and at the same time are finer and more uniformly grained. Moreover cannel-coal frequently shows a uniform microstratification and is more homogeneous in structure than humic coals. Siderite is commonly abundant in cannel-coal. There is a continuous range of transitional stages between cannel-coal and boghead-coal with both alginite and miospores present. Intermediate types can be called boghead-cannel-coal and cannel-boghead-coal. British Geological Survey Research Report RR/99/03, section 6.2 and fig. 10.
| Code | CANL |
|---|---|
| Description | Cannel-coal - A type of sapropelic-coal. It is a dull black, has a waxy lustre, is homogeneous, has concoidal fracture, and is rich in miospores with very little alginite. Macroscopic examination shows no stratification. Microscopic examination shows that compared with humic coals the macerals are more intimately mixed and at the same time are finer and more uniformly grained. Moreover cannel-coal frequently shows a uniform microstratification and is more homogeneous in structure than humic coals. Siderite is commonly abundant in cannel-coal. There is a continuous range of transitional stages between cannel-coal and boghead-coal with both alginite and miospores present. Intermediate types can be called boghead-cannel-coal and cannel-boghead-coal. British Geological Survey Research Report RR/99/03, section 6.2 and fig. 10. |
| Qualifiers | No qualifiers currently exist. |
| Definition | A sapropelic coal. Mud-grade, >75% <0.032mm rock. Miospores > alginite, dull black, waxy lustre, homogeneous, conchoidal fracture. Microstratification & siderite common. Microscopically macerals finer, more uniform & intimately mixed than in humic coal. |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/CANL |
CAVEAT
"Thumbnail" definitions attached to some of the table entries are an interim attempt to provide simple short descriptions of the "unqualified" rock types presented within the BGS Rock Classification Scheme. Every effort has been made to ensure accuracy and consistency but minor contradictions or omissions might be present. The BGS welcomes any feedback pointing out such minor imperfections and/or providing constructive comment and suggestions for improvement of the definitions. In the first instance such feedback should be directed to Dr Tim McCormick.