BGS Rock Classification Scheme

Basalt, lava-pillowed

Code	BALVPW
Description	Basalt, lava-pillowed
Qualifiers	lava   pillowed
Definition	Fine-grained, av. <0.25mm normal crystalline extrusive rock; CI >35 vol% >40 wt%; quartz <20% or feldspathoid <10% of QAPF, feldspar >65% plag; TAS SiO2 45-52wt%, Na2O+K2O <5wt% Material extruded in molten state & solidified into pillow-shaped masses.
Linked data	http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/BALVPW

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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.