BGS Rock Classification Scheme
Phonolitic-leucitite - A type of leucitite. In the Rock Classification Scheme, this rock plots in field 15a on the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram; foids constitute 60 to 90% of light-coloured constituents; alkali feldspar is dominant over plagioclase. British Geological Survey Research Report RR/99/06, sections 5.2, 6.6.
| Code | PNLUC |
|---|---|
| Description | Phonolitic-leucitite - A type of leucitite. In the Rock Classification Scheme, this rock plots in field 15a on the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram; foids constitute 60 to 90% of light-coloured constituents; alkali feldspar is dominant over plagioclase. British Geological Survey Research Report RR/99/06, sections 5.2, 6.6. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Fine-grained, av. <0.25mm normal crystalline intrusive rock containing phenocrysts of leucite (dominant/only feldspathoid); feldspathoids 60-90% of QAPF, feldspar >50% alkali feldspar, +/- mica/pyroxene |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/PNLUC |
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.