BGS Rock Classification Scheme
Microsyenitic-rock - A type of medium-grained normal crystalline rock. In the Rock Classification Scheme, it is the medium-grained equivalent of syenitic-rock. The class includes microsyenite, micromonzonite, and similar rocks. The term may be used as a field classification when an accurate mineral mode from thin section examination is not available. British Geological Survey Research Report RR/99/06, section 5.1.
| Code | MCSYR |
|---|---|
| Description | Microsyenitic-rock - A type of medium-grained normal crystalline rock. In the Rock Classification Scheme, it is the medium-grained equivalent of syenitic-rock. The class includes microsyenite, micromonzonite, and similar rocks. The term may be used as a field classification when an accurate mineral mode from thin section examination is not available. British Geological Survey Research Report RR/99/06, section 5.1. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Medium-grained, av. between 0.25-2mm normal crystalline intrusive rock; quartz <20% or felspathoids <10% of QAPF, feldspar <35% plagioclase +/- mica/amphibole |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/MCSYR |
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.