BGS Rock Classification Scheme

Chalk, marly, glauconitic

Code	CLKGM
Description	Chalk, marly, glauconitic
Qualifiers	glauconitic   marly
Definition	Friable & porous sedimentary rock with particles >50% calcite/aragonite largely of biogenic origin i.e coccoliths. Usually white, particles 0.032-0.25mm. Particles of marl (limey/silty/clay) & lesser green glauconite both 5-20%. Argillaceous limestone.
Linked data	http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/CLKGM

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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.