BGS Rock Classification Scheme
Sapropelite - A type of sedimentary-rock rich in organic matter. Sapropelite and cannel-mudstone are both derived from the unlithified fine organic mud termed sapropel. These sapropels contain more inorganic matter and plant matter than the sapropels that form sapropelic coals. Inorganic sedimentary rocks rich in sapropel are classified according to their type of organic matter. Sapropelite is rich in alginite, whereas cannel-mudstone is rich in miospores. The total organic carbon content (TOC) can vary from less than 1% to as much as 81% in a sapropelite from Tasmania, although most sapropelites fall in the range of 8 to 55% TOC. In the Rock Classification Scheme, it is recommended that the lower limit for sapropelite should be 8% TOC and the upper limit 50% TOC. A sapropelite can be recognised in hand specimen by its bituminous smell and by the curled sliver of rock produced when it is scraped with a pen knife. Sapropelites can be subdivided into lamalginite and telaginite by reference to the properties of the organic matter. British Geological Survey Research Report RR/99/03, section 6.3, table 18 and fig. 10. Synonym: oil shale.
| Code | SAPEL |
|---|---|
| Description | Sapropelite - A type of sedimentary-rock rich in organic matter. Sapropelite and cannel-mudstone are both derived from the unlithified fine organic mud termed sapropel. These sapropels contain more inorganic matter and plant matter than the sapropels that form sapropelic coals. Inorganic sedimentary rocks rich in sapropel are classified according to their type of organic matter. Sapropelite is rich in alginite, whereas cannel-mudstone is rich in miospores. The total organic carbon content (TOC) can vary from less than 1% to as much as 81% in a sapropelite from Tasmania, although most sapropelites fall in the range of 8 to 55% TOC. In the Rock Classification Scheme, it is recommended that the lower limit for sapropelite should be 8% TOC and the upper limit 50% TOC. A sapropelite can be recognised in hand specimen by its bituminous smell and by the curled sliver of rock produced when it is scraped with a pen knife. Sapropelites can be subdivided into lamalginite and telaginite by reference to the properties of the organic matter. British Geological Survey Research Report RR/99/03, section 6.3, table 18 and fig. 10. Synonym: oil shale. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Sedimentary rock dark, pulpy organic mud >75% <0.032mm, alginite>miospores (spores/pollen), usually well preserved identifiable structures. <50 air dried wt% ash. High H%. Dry, ash free C <60%, volat >63%. TOC 8-50%. Bituminous smell. Formerly oil shale. |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/SAPEL |
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.