BGS Rock Classification Scheme

Olivine-gabbro - A type of gabbro. In the Rock Classification Scheme, it is a gabbro with plagioclase 10 - 90%, pyroxene 5 - 85% and olivine 5 - 85% of plagioclase + pyroxene + olivine. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 13, 14.

Code OLGB
Description Olivine-gabbro - A type of gabbro. In the Rock Classification Scheme, it is a gabbro with plagioclase 10 - 90%, pyroxene 5 - 85% and olivine 5 - 85% of plagioclase + pyroxene + olivine. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 13, 14.
Qualifiers No qualifiers currently exist.
Definition Coarse-grained, av. between 2-16mm normal crystalline intrusive rock; quartz <5% of QAPF, feldspar >90% plagioclase (>50% An), plagioclase 10-90%, pyroxene 5-85%, olivine 5-85% of Plag+Px+Ol, +/- mica/amphibole
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/OLGB

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.