BGS Rock Classification Scheme
Amphibolite - A type of metamorphic rock with unknown protolith based on modal composition. In the Rock Classification Scheme, it is one composed largely of hornblende and plagioclase. This mineralogy reflects amphibolite facies conditions. Note that para-amphibolite indicates a rock that is thought to have a sedimentary protolith, and ortho-amphibolite indicates a rock that is thought to have an igneous protolith. British Geological Survey Research Report RR/99/02, section 6.2.
| Code | AMPHB |
|---|---|
| Description | Amphibolite - A type of metamorphic rock with unknown protolith based on modal composition. In the Rock Classification Scheme, it is one composed largely of hornblende and plagioclase. This mineralogy reflects amphibolite facies conditions. Note that para-amphibolite indicates a rock that is thought to have a sedimentary protolith, and ortho-amphibolite indicates a rock that is thought to have an igneous protolith. British Geological Survey Research Report RR/99/02, section 6.2. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Crystalloblastic commonly foliated metamorphic rock (grain size & protolith undefined); 35-90% mafic minerals, hornblende+plagioclase dominant +/-garnet/biotite/quartz |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/AMPHB |
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.