BGS Rock Classification Scheme
Porphyry, biotite-feldspar
Code | PHYBF |
---|---|
Description | Porphyry, biotite-feldspar |
Qualifiers | biotite feldspar |
Definition | Porphyritic normal crystalline intrusive/extrusive rock with aphanitic, (av. <0.25mm) groundmass (composition not defined) biotite<feldspar as phenocrysts both 5-20% |
Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/PHYBF |
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.