BGS Rock Classification Scheme

Metafelsic-rock - A class within meta-igneous rock based on modal composition. In the Rock Classification Scheme, these are coarse-grained meta-igneous rocks containing 65% or more felsic minerals and 35% or less mafic minerals. British Geological Survey Research Report RR/99/02, section 5.2 and figs. 1, 8 and 9.

Code MFELSR
Description Metafelsic-rock - A class within meta-igneous rock based on modal composition. In the Rock Classification Scheme, these are coarse-grained meta-igneous rocks containing 65% or more felsic minerals and 35% or less mafic minerals. British Geological Survey Research Report RR/99/02, section 5.2 and figs. 1, 8 and 9.
Qualifiers No qualifiers currently exist.
Definition Medium to coarse-grained (av. 0.25-16mm), light coloured meta-igneous rock (protolith undefined); <100% quartz, <100% feldspar, <35% mafic minerals of Q+F+mafic minerals; Q+F >65%, +/- feldspathoid; CI<35%
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/MFELSR

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.